Selasa, 31 Juli 2012

Front End Alignment Symptoms

Front End Alignment Symptoms

Front-end alignment refers to the geometric positioning of all the wheels on a vehicle in relation to each other, the vehicle's body, and the road surface. For tires to wear properly and to ensure the correct handling of the vehicle, all four tires should be in parallel with each other and perpendicular to the road surface. Knowing the symptoms of improper wheel alignment can help you avoid abnormal tire wear and possibly hazardous handling characteristics.

Unusual Tire Wear

    When tires begin wearing rapidly or unevenly, it is a sign that there may be a problem with the front-end alignment. When tires become out of alignment in relation to each other, they no longer roll in the same direction as the other tires on the vehicle. This increases the rolling resistance of the tires and also results in the tires effectively dragging against the road surface as they each try to roll in different directions. The end result is greatly increased tire wear and unusual wear patterns. If tire wear suddenly increases or the tires wear only on one side, it is a sign that the tires are out of alignment.

Drifting Right or Left

    Wheels that are out of alignment are in effect no longer pointed in the same direction and may no longer be level with the road surface. This condition results in the vehicle drifting to the right or left while rolling forward. This causes the driver to compensate to maintain a straight direction forward.

Wandering

    An out-of-alignment condition can cause the steering to become overly sensitive and easily affected by uneven road surfaces. The condition exaggerates steering input and the effect uneven road surfaces have on the directional rotation of the tires. The result is a constant need to correct steering and a tendency for the vehicle to wander to the left or right when traveling over uneven road surfaces.

Off Center Steering Wheel

    Most automobile steering wheels are positioned so that the spokes or ribs of the steering wheel are evenly situated to either side when the front wheels are pointed in a straight direction. If the steering or suspension components have become severely worn or damaged, this can cause the steering wheel to no longer be centered in relation to the direction the front wheels are pointed in, and is a sign that the wheel alignment has been altered.

Senin, 30 Juli 2012

Why Does My Coolant Bubble?

Why Does My Coolant Bubble?

Almost all automotive vehicles use a closed-loop, liquid cooling system. The water pump circulates coolant through the cooling tubes of the radiator, where it cools and travels through the engine passages and hoses. Coolant, or antifreeze, is designed to flow smoothly through all of the cooling passages, with no air blockages. A thermostat opens and closes to regulate the coolant flow for engine warm-up and circulation. Air bubbles in the coolant, at the radiator or expansion reservoir, means air has entered the system at some point. This can lead to overheating.

Radiator Cap

    A radiator cap functions as a pressure seal, and keeps the cooling system pressure raised. It also allows pressure and coolant to vent back to the expansion (overflow) reservoir. A malfunctioning radiator cap seal can allow air to enter the system, often producing bubbles in the expansion reservoir.

Air Pockets

    Air pockets in the cooling system usually result from an improper flushing procedure or partial or incomplete radiator fill-up. Air pockets causes a lower coolant volume, often leading to higher than normal operating temperatures. Air will be seen bubbling from the radiator inlet neck or inside the expansion reservoir.

Thermostat

    Thermostats must open fully to allow full coolant flow during normal driving conditions, or must close to allow rapid coolant heating for cold engine start-up. The thermostat mechanism can jam open or closed, leading to under-cooling or overheating, respectively. A faulty thermostat that causes sporadic opening and closing can cause a churning and bubbling effect seen in the radiator or expansion reservoir. The rapid closing and opening of the thermostat valve can also cause a pounding noise inside the radiator, due to the slamming pulses of coolant.

Heater Control Valve

    The heater control valve allows hot coolant to enter the heater core, for the purpose of heating the passenger compartment. A heater control valve with a bad seal at the valve end, or a loose heater hose connection, will allow air into the system.

Expansion Reservoir Hose

    The hose connecting the radiator and the expansion reservoir must be leak-tight at the clamp connections. The hose can not be split or leaking. Air can enter the hose and produce bubbling inside the expansion reservoir.

Water Pump Seal

    A failed water pump seal will allow air to enter the intake or suction side of the pump. This produces bubbling when the trapped air reaches the radiator inlet neck or the expansion valve.

Head Gasket

    Blown or deteriorated head gaskets account for one of the most common and obvious causes of coolant bubbling. If the head gasket material blows between a water jacket and the inner area next to the cylinder, compression gases will enter the water jacket and send air through the head and into the cooling system. Blown head gaskets produce profuse bubbling inside the radiator and expansion reservoir. Rapid overheating results.

Rust and Contamination

    Radiators rust with age, but particularly when they have not been flushed and supplied with the proper antifreeze-to-water ratio. Rust, sludge and debris particles will clog the radiator core tubes, and impair the operation of the thermostat and water pump impeller. Extreme heat and rust will cause the coolant to boil, producing minute bubbles, seen in the radiator neck or expansion reservoir.

Symptoms That Your Car Needs an Alignment

Symptoms That Your Car Needs an Alignment

A car's alignment refers to how the angles of the wheels are adjusted. When a mechanic performs an alignment, he adjusts the angle of the wheels to the proper angle to the ground and to one another. Knowing when you need an alignment may not be obvious, but it is an important part of vehicle maintenance. Bad alignment can result in premature tire wear and steering problems.

Pulling To One Side

    If your car tends to drift towards the center of the road or drifts towards the shoulder of the road, then you could have an alignment problem. You may find yourself constantly applying pressure to the wheel to keep the car moving in a straight line. The reason a car pulls to one side is often because of the camber of the wheels. Camber refers to the angle at which the wheels are lined up with the road. If you are looking at the wheels from the front of the car, the tops of the tires may be pointing slightly inward or outward. If they are closer at the top than at the bottom, then you have negative camber. If the top of the tire is leaning outward, this is positive camber. The slightest wrong adjustment in camber will cause the car to veer to one side or the other. Correcting this alignment issue should keep your car rolling straight ahead.

Wandering

    While an improperly aligned car may consistently pull to one side because of camber, it can also have other steering problems because of caster. Caster is the angle of the steering pivot. When viewed from the side, the caster may cause the steering pivot to lean back or forward. If the steering pivot is too negative, meaning it leans back too far, then the car may have the tendency to wander on the road while you drive. This makes steering in a straight line a constant fight. If it is positioned too far forward, or positive, it could make the steering jerky and too stiff.

Tire Wear

    One of the most obvious symptoms of misalignment is tire wear. The camber as well as toe-in will affect how a tire wears. Toe-in is the distance between the front edge of the two front tires and the back end of the two front tires. If the tires are aligned improperly with regard to toe-in or camber, then it will cause the area of the tire being overused to wear more quickly. Excessively worn out treads on the outside of the tire could mean the camber is too positive, or there is too much toe-in. Inside wear would indicate the opposite alignment problem.

Common Misconception

    A common misconception about poor alignment is that it causes shaking while you drive. Shaking or vibration, while driving, is often caused by a worn-out tire that is out of round, or unbalanced tires. Worn tires may initially be a result of an alignment problem, but the shaking itself is because of the condition of the tires, not the alignment itself.

Sabtu, 28 Juli 2012

What Is an Engine Mount?

What Is an Engine Mount?

An engine mount is just that--it mounts the engine to a vehicle. It keeps the engine from moving or shifting out of place while the vehicle is operating.

Structure

    An engine mount consists of two attached metal parts with rubber in between. One side of the mount is bolted to the engine while the other is attached to the frame. The rubber in the center absorbs vibrations while allowing a small amount of movement.

Function

    The engine mount keeps the engine secured, prevents it from vibrating excessively and ensures that it stays properly connected. It also keeps vibrations from traveling through the frame and other parts of the vehicle.

Malfunction

    Engine mounts may malfunction due to the bolts or rubber on the mount being cracked and worn. The symptoms of a faulty mount include excessive shaking or vibration from the engine and thumping noises from under the hood. If symptoms indicate the engine mount is not secure, it should be replaced right away to avoid damage to the engine.

How to Troubleshoot a Camshaft Position Sensor on a 2002 Pontiac 3.8

The camshaft position sensor on the 2002 Pontiac 3.8-liter engine is a hall-effect switch. It is mounted on the left side of the timing cover, just above the crank pulley. The computer uses the signal from the camshaft sensor to synchronize the sequential fuel injection -- telling the injectors when and how long to open -- and to detect misfires. The sensor has three wires. Working from left to right on the connector they are the ICM positive wire, which has 10 volts, the ICM ground wire, and the CMP signal wire.

Instructions

    1

    Run a key-on engine crank (KOEC) test if the vehicle will not start, by hooking the power graphing meter's red lead to the CMP signal wire and the black lead to a known good ground.

    2

    Follow the instructions on your power graphing meter to get to the waveform screen.

    3

    Watch the screen while cranking the engine. The proper signal on the waveform screen is a square-bottomed "U." You should see several of these in a row. The bottoms of the signals should be even with each other. If you see any other pattern, the camshaft sensor is bad.

How to Troubleshoot a 7.3L Turbo Diesel

The 7.3-liter turbo diesel engine is the largest displacement engine in Ford's Power Stroke series. The 7.3-liter Power Stroke was available in the Ford E-Series vans manufactured between 1994 and 2003. Though Ford's various turbo diesel engines are known for their long-term reliability, various issues with the engine and turbo system issues can arise, especially on high-mileage engines. Any issues or malfunctions should be troubleshooted immediately to avoid the development of more complicated issues.

Instructions

    1

    Check the gauge cluster to see if the "Check Engine" light is activated. Most turbo system malfunctions, as well as other engine and emissions system issues, will activate the "Check Engine" light, making for an easy diagnosis.

    2

    Plug an ECU code reader into the ECU OBD-II port, located in the driver's side footwell area. If you don't own an ECU code reader, many automotive service departments offer free error code reading service. The code reader will display any error codes responsible for the "Check Engine" light, as well as a brief description of the malfunction.

    3

    Find a safe road to accelerate the engine under heavy throttle, allowing the turbocharger to spool. While accelerating, listen for signs of turbocharger malfunction. This can include excessive turbocharger whine or whistling noises. In extreme cases, grinding noises may be present due to worn turbo bearings. If your turbocharger shows these signs of wearing, it should be replaced or rebuilt immediately to ensure the continued performance of your turbo diesel engine.

    4

    Examine the various turbo system components in the engine bay for signs of wear or loose hose connections. This includes the intercooler piping system, as well as any turbo vacuum lines. Rubber lines and connections are especially prone to wear due to the extreme heat generated by the engine and turbo system. Worn lines and hoses should be replaced to avoid boost pressure leaks, which can substantially lower the performance and reliability of your engine and turbocharger.

Jumat, 27 Juli 2012

1995 Chevy Blazer Won't Start

1995 Chevy Blazer Won't Start

The 1995 Chevy Blazer is known for being rugged and reliable. But a vehicle that won't start can be discouraging. Every vehicle needs five basic elements to start: fuel, air, spark, timing and compression. Determining which of these elements is missing determines how to proceed in repairing your Chevy Blazer.

Instructions

    1

    Check the battery. Even if the vehicle will turn over, if it turns over slowly, or battery voltage is too low, the vehicle will not start. With the multimeter, check voltage of the battery. It should be between 12 and 13 volts. Have an assistant crank the engine. If the battery voltage drops below 9 volts while the starter is engaged you have a battery or charging system issue. If the battery is good, move on to step two.

    2
    Ensure there is fuel in the vehicle.
    Ensure there is fuel in the vehicle.

    Check for fuel. First ensure that your fuel gauge is working, and there is actually fuel in the vehicle. Secondly, check for fuel at the engine. Remove the air cleaner, and watch the injector at the throttle body for fuel. A smooth "fan" of fuel should come out when the engine is turned over. If it does not, there is a fuel pressure problem, most likely a fuel pump.

    3

    Check for spark. Using a timing light, place the clamp over the number one spark plug wire. Have an assistant engage the starter, or do so with a remote starter switch. When the engine is turned over, the timing light should flash. If it does not, there is no spark, and you need to begin testing ignition components. The most common cause of no spark on a Chevy Blazer is the ignition control module, located under the distributor cap or on the distributor. Take this to a local auto parts store to be tested, and replace it if it tests bad. If it tests favorably, test the coil, and replace if faulty

    4

    Check the timing. While the distributor cap is removed, ensure that the distributor rotor is turning. If it is not, either the distributor shaft is damaged or the timing chain is damaged. Pull the distributor first, and check the shaft and gear for damage. If intact, the problem is in the timing chain, and will require major engine work to repair. If the rotor is turning, check the timing using the timing light. With the clamp still abound the number one plug wire, and the distributor cap installed, aim the timing light down at the harmonic balancer while an assistant cranks the motor. Depending on the engine in your Blazer, timing should be around three to six degrees before top dead center (TDC) there will be a mark for this on the timing tab of the timing cover. If timing is off, adjust the distributor to adjust timing.

    5

    Check for compression. Remove a spark plug from the spark plug hole. Screw in the adapter for the compression tester, and attach it. Have an assistant engage the starter for a few seconds. Check the reading on the compression tester, and compare it to compression specifications for your motor, usually in the 100-120 psi range. If compression is low, there are several possible causes, all involving major engine repairs. Consult a professional to further diagnose the cause of low compression, and evaluate options.

Signs of a Carburetor Going Bad

Signs of a Carburetor Going Bad

When a car's carburetor goes bad, engine performance can be seriously compromised. A working carburetor ensures proper flow of fuel and air into the engine. Many cars on the road today still use carburetors, and it is important for them to be functioning properly in order for their engines to operate safely and efficiently.

Black Exhaust Smoke

    When a carburetor is working correctly, the flow of air and fuel into the engine is balanced and efficient, and the exhaust smoke should be thin and gray. When a carburetor is going bad, one of the first signs is thick black smoke coming from the exhaust pipe. Black exhaust smoke is a sign that the ratio of air to fuel in an engine's combustion chambers is imbalanced.

Hard Starting

    In order for an engine to start effectively, a large amount of both air and fuel is required to flow into the engine's combustion compartments. A bad carburetor usually restricts the flow of both air and fuel into the engine. If a car's engine isn't starting normally, it could be a sign of a bad carburetor.

Engine Hesitation

    A bad carburetor often causes an engine to stumble, or hesitate, during acceleration. When fuel cannot flow efficiently into the engine, it is difficult for the engine to provide steady acceleration. The carburetor assists the free flow of fuel into the engine's combustion chamber; thus a common sign of a carburetor going bad is engine stumbling under heavy acceleration.

Signs of a Leaking Head Gasket

Signs of a Leaking Head Gasket

Head gaskets form a seal from the head to the engine block. The head gasket is subject to numerous failures, including bursting at the edges, burning and separating at critical oil-and-water passage junctions and leaking. If the head gasket fails, the head can suffer extreme heat and contort, further opening up critical seals. Water and oil can cross passages and pollute other fluids. Vehicle owners can learn how to recognize when this happens with some telltale signs.

Aluminum, High-performance Heads

    Aluminum heads save on weight and dissipate heat rapidly, but they can contract and expand much more rapidly than cast iron heads. Distorted aluminum heads can cause a separation in the combustion chamber, producing hissing or "plapping" noises. These signal that exhaust gases have blown through the outer gasket ends. Once a head has warped, it breaks the head gasket seal, allowing exhaust gases to escape. A compression test on a cylinder can reveal a low compression reading where the head has warped and failed to seal. Water and oil jackets can cross, showing fluid leakage from the seam between the head and the block.

Contaminated Water

    Oil in the radiator water will be seen at the filler neck after taking the cap off. A light brown, sudsy froth means that oil has entered the water jackets, probably through the head passages. The overflow reservoir will also show signs of contamination, with a thick, rusty looking coating inside the tank. The vehicle will run noticeably hotter and may even overheat, which could lead to hard starting and stalling. Steam vapors may rise from the radiator, indicating the oil within has reached its boiling point.

Water in the Oil Supply

    Water in the oil will be visible on the oil dipstick as a beige or orange-colored froth or foam. This discolored oil might pass through the PCV valve and splatter the top of the valve cover and even the inside of the air cleaner, causing the engine to misfire. Water in the oil causes the viscosity of the oil to break down (lose its thickness) and can eventually rust bearings and bushings. Water can also be trapped in the oil filter, where it accumulates and destroys the filtering elements in the oil filter.

Fouled Spark Plugs

    Spark plugs that have fouled electrodes may appear white, yellow or brown, which indicates that water has passed into the cylinder and burned. The plug will almost certainly misfire or fail completely. This indicates a leaking head gasket or, in some cases, a warped head. Plugs that appear black and have a slick, oily appearance mean that oil has contaminated the plugs because of an oil passage leak in the head gasket. These fouled plugs can cause a cylinder to miss every time the plug needs to fire.

Water Emissions from the Tail Pipe

    A water jacket that crosses over to the intake combustion side of the head can cause water to enter the intake valve and travel through the exhaust system. Dripping or spraying water or steam can be seen exiting the tail pipe, especially under rapid acceleration. This condition can cause overheating, engine stalls and hard-starting. A knocking noise sometimes accompanies this condition because water cannot compress inside the cylinders, which results in misfires.

Kamis, 26 Juli 2012

Why Auto AC Shuts Down at 90 Degrees

Why Auto AC Shuts Down at 90 Degrees

Air conditioning is a comfortable feature in automobiles, especially if you live or drive in a hot region. An automobile's AC system contains a few parts that may fail at the worst time, such as when the temperature reaches 90 degrees Fahrenheit.

Identification

    An automobile AC system consists primarily of a compressor, condenser and an evaporator. Each of these components uses refrigerant supplied through connecting hoses.

Effects

    The AC compressor has an automatic safety switch that activates if the component senses low, or leaking, refrigerant levels. The compressor's internal clutch will not function when the refrigerant level is low. This may result in a shutdown of the AC at higher temperatures.

Significance

    The compressor's safety switch protects the system from overheating in 90 degree weather. Irreversible damage to the compressor and other connected components can occur without this safety mechanism. AA1 Car suggests checking the refrigerant level as you look for the cause of a shutdown.

How Do I Troubleshoot a 2006 F150 Truck That Will Not Go Into Four- Wheel Drive?

How Do I Troubleshoot a 2006 F150 Truck That Will Not Go Into Four- Wheel Drive?

Some 2006 Ford F-150 pickup trucks were sold with four-wheel drive transmissions that supply power to all four wheels when needed. The four-wheel drive system isn't in use all the time, and Ford only recommends using it under certain pavement conditions since drive-train damage can occur on dry pavement. In addition, shifting to and from four-wheel drive only can be obtained under certain conditions. Troubleshooting can be accomplished by following a few simple steps.

Instructions

    1

    Engage the four-wheel drive low gears when the correct speed is obtained. Lower the vehicle's speed to below 3 mph before engaging four-wheel drive "low" if the vehicle is equipped with the electronic shift "4WD" system or the manual system. You can tell if the system is electronic because the it is operated with dashboard controls rather than a lever near the gear shift.

    2

    Make the shift into four-wheel drive "low" while coasting at 3 mph if the truck won't go into four-wheel drive "low" when stopped.

    3

    Move the lever on a manual system at speeds up to 55 mph, to shift between two-wheel drive "high" and four-wheel drive "high" if the truck won't go into four-wheel drive. Don't attempt the shift at speeds greater than 55 mph.

    4

    Wait for the ambient temperature to go above 32 degrees if you want to make the shift at speeds up to 55 mph. If the ambient temperature is bellow freezing, make the shift at 45 mph or lower.

How to Troubleshoot Problems With the HVAC on a 2004 Chevy Pickup

How to Troubleshoot Problems With the HVAC on a 2004 Chevy Pickup

GM's 2004 Chevrolet Pickups were available with heaters, heater and air conditioning combinations and a dual automatic climate control system that allows for separate settings for passenger and driver. Problems with the systems can be related to the temperature being incorrect, the air flow not being adequate, and environmental issues like misting and odors. Problems like these can be rectified through troubleshooting.

Instructions

    1

    Clear snow, ice and leaves from the air inlets at the base of the Chevy pickup's windshield if the HVAC system isn't working right. This vent is the master input vent and is very important because it provides the air throughput for heating, cooling and ventilating.

    2

    Remove shopping, toys and other items from underneath of the front seats in extended cab pickups that use rear seating. Air is distributed to the rear through vents under the front seats.

    3

    Uncover the sensors if temperature isn't being maintained on the automatic system. Sensors are found in the headliner, and there's also one in the defrost grille in the middle of the instrument panel that monitors solar heat.

    4

    Turn the air conditioning part of the HVAC to "Recirculation" if outside odors are entering the pickup. "Recirculation" can't be used with "Floor," "Defrost," or "defog" modes, however. The indicator light flashes three times if you try.

    5

    Try removing any hood deflectors if you continue to have problems. GM says that its hood deflector won't cause HVAC problems, but that other makers' devices could affect air distribution.

Rabu, 25 Juli 2012

Power Window Failure

Many of today's cars come with power windows as a standard feature. Occasionally these windows can fail to work properly due to a mechanical or electrical fault.

Symptoms

    A power window failure can display different symptoms depending on the exact cause of the fault. Car owners should check to see whether they hear motor noise when they try to activate the window, whether the window will move in one direction but not the other, or whether the other windows exhibit a similar failure.

Causes

    A single power window failure may stem from a failing window motor, a problem with the wiring leading to the motor, a broken window linkage or misaligned window tracks. If the electrical line relaying power to the power door system breaks or blows a fuse, all the the car's power windows fail at the same time.

Repair

    Most troubleshooting and repair operations require removing the car door panel, although sometimes the troubleshooter can simply pull the window switches out of their housings to check the electrical connections with a voltmeter. With the door panel removed, a repair shop can replace faulty motors or broken linkages.

Selasa, 24 Juli 2012

How to Troubleshoot a 1997 Nissan Maxima

How to Troubleshoot a 1997 Nissan Maxima

Nissan Maximas are well known for their durability and reliability, with some lasting well over 200,000 miles. However, as with all vehicles, even a well-maintained Maxima will break down sooner or later. Knowing how to troubleshoot potential problems before they become worse can help save you time and money when you do the work yourself. Becoming familiar with tools and fluids used in your 1997 Maxima will also help to identify leaks, which can lead to further problems if they are not addressed.

Instructions

    1

    Turn the key in the ignition of your 1997 Maxima and note the response of the interior lights and headlights. If they are weak or are not turning on at all, then you have a dead battery. Try jump-starting the battery or replace it if it won't hold a charge. Gently shake the battery connections and inspect the battery terminals for signs of corrosion. If the terminals are corroded, pour a bottle of soda over the connections and scrub them with a wire brush. If the Maxima makes a prolonged or strained sound while the engine is turning over, then the starter may be failing. If the lights are at their usual brightness when you turn them on, then your starter has failed. Try tapping the starter with a hammer to coax it into re-engaging with the flywheel.

    2

    Look underneath your engine for small pools of leaking fluid. Motor oil is a thick substance that is either brown or black, depending on how old it is. Engine oil should be changed at every 3,000-mile interval. If the oil is leaking and is extremely dark, then you may need to change it more frequently. Engine coolant is typically a green color and can indicate a radiator hose leak. Refill the coolant's reserve tank with a 50/50 solution of coolant and distilled water. Red solution is either brake or automatic transmission fluid. Check the levels in both of the fluid reservoirs to ensure that they are at the appropriate marks.

    3

    Lift the Maxima with a floor jack to inspect the brake pads and rotors. You can inspect the pads on a 1997 Maxima without taking them out of the calipers to see how much of the pads is left. Possible signs of brake failure include squeaking or grinding when the pedal is depressed, if the vehicle pulls to one side while braking or when the pedal offers little resistance when it is depressed.

    4

    Listen for squealing and squeaking sounds from the drive belts while starting your Maxima or while driving. Excessive noise may indicate that the belt needs adjusting or replacement. Belts with signs of fraying should be replaced immediately. Belts should be tightened so that they deflect between 1/4 and 1/2 inches when pressure is applied to the belt's center point between the pulleys.

A Jeep CJ7 With Steering Problems

A Jeep CJ7 With Steering Problems

AMC introduced the Jeep CJ-7 in 1976. With a production run that lasted 10 years, the CJ-7 was the first with an automatic transmission and optional hard top and air conditioning. It became one of AMC's most popular vehicles with more than 300,000 made. With CJ-7s now approaching 25 years of age, many mechanical parts start to show wear, affecting the drivability of the vehicle.

Pulling

    Uneven tire pressures or incorrect front-end alignment are simple causes of this symptom. More serious problems with the suspension or steering components or wheel bearings need to be checked.

Vibration

    Check for loose lug nuts or a tire or wheel out of balance. Ensure that the steering gear is mounted tightly and adjusted correctly. Also inspect the idler arm and ball joints for wear or damage.

Stiffness

    Check the fluid levels of the power steering reservoir. Lack of power steering fluid reduces the effectiveness of the pump and causes it to be noisy. As a result, the steering effort is not the same in both directions. Check the lubrication of the ball joints and the steering linkage.

Play

    Loose wheel bearings can cause this problem. Excessive wear in the steering linkage or suspension bushings cause loose play while steering. If the steering wheel fails to return to center, check for a misaligned steering column or improperly engaged steering gears.

Why Does the Overdrive Light Blink?

Why Does the Overdrive Light Blink?

On Ford vehicles, the transmission overdrive light will blink to indicate a transmission problem in the same way a blinking check engine light indicates an engine problem. The overdrive light will blink when the vehicle's computer registers a transmission check code. To rectify the problem, you will need to have the transmission code read and the system diagnosed.

Blinking Overdrive Light

    In order to diagnose the problem, be sure to document when the overdrive light began to blink and any transmission problems such as slipping, excessive noise or harsh shifts. For instance, if the overdrive light blinks after an hour on the highway, that may indicate a cooling issue. While turning off the vehicle and restarting may make the light go away, this is not a permanent fix and will delay needed repairs, which can cause greater damage.

Basic Corrective Step

    If the overdrive light is blinking, do not simply keep driving. While transmission are complex devices best left to professionals, you can make check a few basic things yourself. Check the transmission fluid to make sure it is not low or empty. There will be a transmission dipstick in the engine bay. The fluid should be red and at the full line on the dipstick. If the fluid is low, or if it is dark and emits a burning smell, the transmission fluid is bad and may be the explanation for transmission failure.

Transmission Codes

    Take your vehicle to the dealership or an independent shop to have the transmission codes read and diagnosed. Once the shop reads the codes, they will be able to diagnose the problem. Provide the shop with the information you collected about how the vehicle drives, when the light comes on and any hard shifting or other transmission problems.

Do Not Delay

    It is important you immediately visit a qualified shop when your transmission overdrive light begins to blink. Delaying a visit may cause additional harm or damage to the transmission and can greatly increase the eventual repair bill. Remember that the blinking light means there is a problem that needs to be fixed, not ignored.

How to Troubleshoot a Fuel Smell in a Quadrajet Carburetor

Summit Racing produces the Quadrajet Carburetor for performance use. The carburetor is most often found in race cars or high-performance carbureted engines. Whether you are using a new Quadrajet or a rebuilt model, problems arise with extended and heavy use. One issue that poses a concern is the odor of fuel emanating from around the carburetor. With the explosive nature of fuel and fuel vapors, odors related to fuel raise concerns.

Instructions

    1

    Inspect the fuel lines leading into the carburetor. Look for signs of a fuel leak. As fuel evaporates quickly, look for clear streaks where the fuel cleansed the area as it dripped.

    2

    Locate and inspect the evaporative canister. The canister traps vapors escaping the engine and if it becomes clogged, can cause a strong odor of fuel to appear in the carburetor. The charcoal evaporative canister is connected to the carburetor by a vapor line going to the top of the float chamber.

    3

    Check the fuel injectors inside of the carburetor. Look for scoring or marking on the injectors. Inspect for dirt and debris. A clogged or plugged injector could be spraying fuel incorrectly leaving residue and odor.

    4

    Start the vehicle and allow it to run until it reaches operating temperature. While running, if the smell remains but none of the above steps identified an issue, then remove the air filter and visually inspect the injectors. If you notice one spraying abnormally, clean the unit with carburetor cleaner. If they all appear to be spraying correctly, the issue is with the fuel delivery system.

    5

    Let the vehicle rest for 15 to 20 minutes. If the odor remains or you had issues getting it started initially and continue to have those issues, the problem likely lies with the fuel delivery system such as the pump or fuel lines.

Senin, 23 Juli 2012

Toyota Tundra Idle Problems

Toyota Tundra Idle Problems

Poor idling in a Toyota Tundra truck may result from a number of sources and not one predictable cause. Whatever the case, the problem can be frustrating until resolved, particularly when the truck dies out at a stop sign or when waiting with the engine in park. However, a few simple fixes can sometimes locate and solve the problem quickly.

Fuel Injectors/Throttle Body Plugged

    Tundras have fuel injection rather than a carburetor, which provides frequent source of idle failure from either plugged-up fuel injector nozzles or a dirty throttle assembly. Both areas gunk up from the use of cheap gas. Using injector cleaner solution helps somewhat, but eventually a professional repair is required.

Spark Plug Check

    One of the most basic areas of engine ignition includes the spark plugs. However, people rarely check them, not really knowing how to do so. Sparks wear out over time from constantly burning and need replacement. Usually, they get swapped out during a tune-up.

Dirty Intake

    Air intake provides critical oxygen sources for the engine to use in the combustion process. If the intakes or the air filter are clogged and/or dirty, the truck engine idle will perform badly. However, the air filter can be easily exchanged with a new one on a regular basis.

Mercedes Code 219

Mercedes Code 219

Modern cars use on-board diagnostic computers to relay information to mechanics regarding faults sensed by the diagnostic system. The codes are 4 digits preceded by a letter, so in this case the full code would read P0219.

P0219

    P0219 is a universal (used by all car manufacturers after 1996) code with the technical description "Engine Overspeed Condition." The fault code has been raised because the engine speed exceeded the calibrated limit set by Mercedes.

Causes

    Wheel slippage on an adverse surface, such as water, ice, mud or snow, could cause this fault to be sensed. High revolutions or engine RPM with the transmission gear in neutral or in the wrong gear also could cause this code.

Clearing the Fault Light

    The error code P0219 is likely to have been caused by driver errors or road conditions. To ascertain that this is the case, the code must be reset. The exact method of resetting an engine fault varies between years and models. The car owner's manual for the specific model should have instructions to guide you through the process.

Minggu, 22 Juli 2012

How to Test a Fuel Pump Relay on a 94 Ford Ranger

How to Test a Fuel Pump Relay on a 94 Ford Ranger

A broken fuel pump relay causes a malfunctioning pump, starving the engine of fuel. The engine may stutter, stall or not start at all. Luckily, you can test the fuel pump relay in a 1994 Ford Ranger without buying any additional parts, relays or special tools. Almost all novice mechanics can test the fuel pump relay in a few minutes to determine whether there's a need for further diagnosis, or whether the fuel pump relay is the source of the mechanical troubles.

Instructions

    1

    Locate the fuse and relay box in the engine compartment. It is located near the firewall on the driver's side of the engine compartment.

    2

    Pull the cover from the relay and fuse box.

    3

    Pull out the fuel pump relay with needle-nose pliers. The relay is located in the middle row with 13 fuses in the row. The fuel pump relay is the third relay from the right.

    4

    Pull the relay that is fifth from the right. Insert it into the empty fuel pump relay, third from the right. Insert the relay removed originally from the third slot and insert it into the fifth position from the right.

    5

    Start the vehicle. If the engine stalls, stutters or does not start, the fuel pump relay is bad. Remove the original fuel pump relay from the fifth slow from the right. Remove the replacement relay from the third slot from the right and insert it into original position in the fifth slot. Bring the original fuel pump relay to an auto part store and buy a replacement. If the engine does not stutter, stall and starts as it should, place the relays in their original positions and diagnose other areas of the fuel system.

    6

    Insert the new relay into the third slot from the right.

    7

    Place the cover onto the fuse box.

Sabtu, 21 Juli 2012

Toyota Truck Problems

Toyota Truck Problems

Toyota throughout the years has enjoyed a long-standing reputation for quality and reliability in its trucks. However, that reputation failed to prevent various issues from cropping up from time to time regarding its trucks and their performance. Many of the issues tend to be associated with the engine, electronics or the braking system.

Brakes

    Since its introduction in the 1970s, the Toyota truck has enjoyed a reputation for being able to drive hundreds of thousands of miles before breaking down. However, in the late 1990s the first major recall occurred with the Tundra brake system and mismatch of calipers. The result was easily warped rotors needing expensive change-outs in less than 15,000 miles.

Fuel Injection

    With the switchover from carburetors to fuel injection systems, trucks also began to suffer gumming up of throttle body assembly and fuel injectors. While retail fuel injector cleaners delayed this problem for a while, eventually Toyota owners would find themselves paying for professional cleanings of systems.

Gas Switch Issues

    In the late 2000s Toyota trucks suffered from the same recall issue as other Toyota vehicle models with a faulty electronic gas pedal switch. While following the industry in switching over to electronic throttle systems and doing away with cable activators, Toyota trucks suffered electrical failures as accelerators stuck and caused accidents.

Jumat, 20 Juli 2012

Oil Light Is Flashing in a Dodge Caravan

Oil Light Is Flashing in a Dodge Caravan

There are two indicator lights on the Dodge Caravan instrument panel that flash to alert you to problems with your oil. One reads "Change Oil," when you need an oil change, and the other, shaped like an oil can, is the oil pressure indicator light.

Oil Pressure Warning Light

    If the oil can light is lit, check your oil.
    If the oil can light is lit, check your oil.

    The indicator light shaped like an oil can is located on the bottom of the middle instrument panel. When this indicator is lit, your engine has low oil pressure. It's normal to see the light when you turn your car on, but if it does not go off, or if it flashes while you are driving, turn off the vehicle as soon as you can and check the oil level.

Change Oil Light

    Change your oil when the Change Oil light flashes.
    Change your oil when the Change Oil light flashes.

    The Change Oil indicator light is located either on the tachometer dial in a premium model or on the temperature gauge dial in a base model. When this light flashes, you need an oil change. In addition to these words flashing for 12 seconds, a single chime will sound. The time between oil changes may vary, depending upon your driving conditions.

Reset the System

    The accelerator pedal needs to be pressed three times to reset the system.
    The accelerator pedal needs to be pressed three times to reset the system.

    Once you have changed your oil, you must reset the system, or the light will continue to stay lit. Turn the ignition switch to On, but do not start the Caravan. Push the accelerator pedal all the way three times, very slowly, but within 10 seconds. Turn the ignition off. The light should now stay off.

How to Use Engine Diagnostic Machines

How to Use Engine Diagnostic Machines

In 1996, by order of the Environmental Protection Agency, engine diagnostics became standardized for vehicles sold in the United States. As a result, diagnostic coding is the same in a Ford as it is in a Chevrolet or a Chrysler. The process of accessing a vehicle's second generation on-board diagnostic system is the same, as well. A handheld computer is needed. The functionality this type of device covers a broad spectrum. Cheaper, simpler diagnostic machines are simple OBD-II code readers, while the more sophisticated scanner can do much more.

Instructions

    1

    Insert your diagnostic machine into the your vehicle's data link connector. For most vehicles, this 16 pin-receiving outlet can be found in the leg space on the driver's side of the vehicle. It will either be under the steering column or to the left or right of the steering column.

    2

    Switch the diagnostic machine on. Some of the higher end scanners have a self-activating feature, whereas some of the more simpler code readers may need to have the power button pushed.

    3

    Turn your vehicle's electrical system on. Doing this depends on the brand and type of OBD-II scanner. Some will need to have the engine running.

    4

    Issue a retrieval command. How to do this also depends on the specific device you own. Button locations do vary and some scanners use a manu system. Also, some scanners are preset to automatically pull codes from a vehicle's computer, once a data stream is sensed. For the exact instructions on how to do this, consult the manual of the device you own.

    5

    Look at the codes on the device's screen. Often, they will be differentiated by their status in the vehicle's computer. Some codes will be labeled as "faults" or "trouble." This means the codes have happened quite frequently, and the system has activated you vehicles service engine soon light. Other codes will be labeled as "pending." These are still recorded malfunction, but they have occurred a little less frequently than fault or trouble codes. Pending codes do not active a vehicle's service engine soon light.

    6

    Look at the first character in the OBD-II codes on the screen. This letter will tell you where to look for the problems. "P" stands for "powertrain," and the codes correspond with problems in the engine. "C" stands for "Chassis" and the codes correspond with issues in the electrical system. "B" stands for "Body" and correspond with mechanical issues not associated with the engine. "U" stands for network communication

    7

    Look on your device for something akin to "live data." Simpler code readers may not have this function. You can shift out of code reading mode and obtain readings from your vehicle's many sensors. This way, you can find outoil pressure and engine revolutions per minute. If your scanner has this feature, it quickens the troubleshooting process. Many of the OBD-II codes correspond with specific engine sensors. If you have only a simpler code reader, you will have to check these sensors independently, usually with a continuity tester and a volt meter.

Exhaust Leak Tips

Exhaust Leak Tips

The exhaust system has the important job of directing and expelling combustion gases from the engine out the tailpipe. Sometimes restrictions block the flow of burnt gases and cause leaks. Other times the exhaust system pipes and components can loosen at their connections, which can cause leaks that can be seen and heard. The exhaust system starts with the exhaust manifold and ends at the tailpipe. Everything between the front and rear of the exhaust system can be checked for leaks and repaired.

Exhaust Manifolds

    The exhaust manifold gasket takes a lot of punishment in the form of expansion and contraction. The gasket can fail due to the stresses and pressures it must endure and usually gives warning signs. Hissing or popping noises coming from the manifold indicate a possible leak. Any black soot in and around the manifold mating surface to the head indicates escaping exhaust gases. Look for melted plug wires, where excessive heat has caused burning. Another indicator will be the release of carbon monoxide that enters the passenger compartment. Carbon monoxide fumes can cause dizziness, nausea and confusion. Cracked exhaust manifolds can emit loud rumbling or "plapping" noises, sometimes in a very low frequency.

Manifold to Header Pipe

    Catalytic converters should be checked for corrosion and blockage.
    Catalytic converters should be checked for corrosion and blockage.

    The manifold to header pipe connection typically has a large graphite gasket or a metal ball and socket-type flange. On vehicles with front-wheel drive, this joint takes a lot of flexing from engine movement during shifting and hard acceleration, causing the joint to flex and wear out. Leakage from this gasket joint will often cause very loud rumbling sounds and smell like unburned fuel. Black smoke can sometimes emit from this joint. Any discoloration at this joint like soot-streaking or black carbon buildup will point to a bad manifold to header pipe junction. Once again, carbon monoxide will be a real danger in this area.

Catalytic Converter

    The catalytic converter re-burns excessive fuel that has come from the combustion chamber by using extreme heat and a chemical reaction. If it gets too hot it will discolor on the outside casing (underneath the shields), showing a multi-colored rainbow pattern, a sign that it has burnt internally. The chemical pellets inside the converter will give off a rotten egg smell when the engine has warmed up. A clogged or saturated converter will create huge back-pressure that will send exhaust gases backwards and out through points of least resistance like the manifold to header joint or the exhaust manifold gasket. A bad catalytic converter should be replaced immediately.

Mufflers and Resonators

    Mufflers and resonators dampen exhaust noise and can be found mounted mid-way under the chassis or at the extreme end near the tailpipe. They collect the most water condensation and can rust from the inside out. Sometimes drain holes can been seen on their bottom casings. Any rusty water dripping out of the drain holes indicates interior rusting, where the baffle plates have deteriorated. Mufflers and resonators typically rust starting at the bottom. So any flaking or rotted metal indicates a partial or full failure of the interior structure and a leak can be expected in this area before too long.

Pipe and Component Joints

    Any place in the exhaust system where a clamp couples a pipe to a muffler, catalytic converter or resonator can weaken and break. Joints will give way first, whether mechanically sealed or welded. Other suspect areas for leaks will include locations where any sharp bends exist in the pipe, like the over-the-axle loop. Pipe and muffler hangers can break free and let the exhaust hang, hitting and abrading other parts of the chassis, eventually causing mechanical damage.

Kamis, 19 Juli 2012

What Causes the Check Engine Light on a Buick Century?

What Causes the Check Engine Light on a Buick Century?

A Buick Century can indicate one of several problems when the check engine light comes on. Some of the older Buick Century's have a yellow warning light and a red warning light for the check engine. The yellow light means the problem is minor, but if the red light comes on, the car should be stopped as soon as possible because there is something seriously wrong with the engine.

Wiring Harness

    The check engine light can come on in a Buick Century if the wiring harness resting next to the air-conditioning unit is damaged or chafed. This minor damage to the wiring harness can be caused by vibration or rubbing of the harness against the metal parts of the air-conditioning unit. Over the course of operation, the wiring harness rubs up and down during normal driving conditions.

EGR Valve

    Each Buick Century has a exhaust gas recirculation (EGR) valve on the engine. The valve is an integral part of the car's emission system, which helps the car burn fuel more efficiently. When this valve is not operating properly, the check engine light comes on and requires the valve to be changed out. If the EGR valve is not switched out or replaced, the Buick Century does not get the same fuel mileage as it would usually get during normal driving conditions.

Vacuum Leak

    A check engine light can also be caused by a vacuum leak from one of the hoses that run throughout the engine of a Buick Century. The specific type of vacuum leak or where the vacuum leak is coming from can be diagnosed by the code that is issued with the check engine light. For example, the number on the code can tell the repairman what sensor needs to be replaced such as the front oxygen sensor. This code can also be caused by the engine misfiring.

Coolant Tempurature

    The engine coolant temperature (ECT) sensor can be going bad or the coolant temperature can be too high. A ECT sensor has a high and low range. If the coolant that circulates through the engine and radiator falls above or below this range, the check engine light can come on and warn the operator of the Buick Century.

How to Use the Modis to Unlock Parts

MODIS--Modular Diagnostic Information System--is a scanner used for checking diagnostic problems with a vehicle's computer system. These diagnostic systems are otherwise called computer scanners and plug directly into the vehicles computer port, typically located under the steering wheel. When running a diagnostic check, the technician is required to access the part code where the computer suspects the problem to be occurring. Pressing a series of buttons will reveal the suspected problem parts and the corresponding part codes.

Instructions

    1

    Insert the key into the ignition. Turn the vehicle battery on. Note that you don't have to turn the engine on; simply ensure that the battery and vehicle electricity is running.

    2

    Plug the MODIS scanner plug into the vehicle's computer port. Depending on your vehicle, location of this port may vary, but is typically under the front dashboard beneath the steering column.

    3

    Use the MODIS thumb pad to move the cursor to the "View" icon located in the top left corner. Press the "OK" button. Allow the MODIS to run the diagnostic check.

    4

    Move the cursor to the top right corner onto the tool-box icon. Press the "OK" button. The MODIS will unlock the parts list and display the problem parts on the screen. Note that most parts are abbreviated.

Rabu, 18 Juli 2012

How do I Reset a P0174 Code on a Cadillac?

How do I Reset a P0174 Code on a Cadillac?

For Cadillacs and other cars, P0174 is an On-Board Diagnostic trouble code meaning "System too lean (Bank 2)." The oxygen sensor in the second bank has detected too much oxygen in the Cadillac's exhaust. To fix this, you will likely have to troubleshot all the hoses, change a dirty fuel filter, and clean or replace the mass air flow sensor. However you address the situation, after the repair work is complete, you will need to clear the trouble code, P0174, from your Cadillac's diagnostic system. The hard job is behind you. Resetting your OBD-II system will take only a few seconds.

Instructions

    1

    Close the hood of your vehicle and open your driver's side door. Place the Cadillac's key into the ignition and leave it unturned.

    2

    Hook your OBD-II code scanner up the Cadillac's data link connection beneath the dashboard. Depending on your model of Cadillac, it will be to the right or left of the steering wheel.

    3

    Turn your scanner on.

    4

    Turn the key in the Cadillac's ignition to "On," but do not start the engine.

    5

    Press and hold down the "Erase" button for 3 seconds. If you have fixed the problem, the P0174 code will disappear. If it does not, you will have to review your repair work.

Selasa, 17 Juli 2012

List of Dashboard Warning Lights

List of Dashboard Warning Lights

Cars have become more reliant on computers, increasing the complexity of various systems and sometimes making problems harder to solve. Several dashboard warning lights alert the driver to severe or mild system malfunctions. According to a survey conducted for Great Britain's Automobile Association (AA), 47 percent of women and 33 percent of men could not diagnose the meaning of warning lights. Most vehicle handbooks can identify and define the problem, and should be referred to by every vehicle owner.

Oil Pressure Warning Light

    The oil pressure warning light is red. It lights when the engine is started, and blinks off after a few seconds. If the light remains on during driving, the driver should pull over to a safe spot and shut the engine off. This light means dangerously low or no oil pressure inside the engine. Check the oil level at the dip stick and add oil to the prescribed level indicated on the stick.

Battery Charge Warning Light

    The battery charge warning light is red and should momentarily turn on during starting and then extinguish. If it does not come on at all or remains on after the engine has been running, it means a problem with the charging systems (alternator or generator) exists. Problems could include bad battery cable connections, a defective alternator or generator, or a broken alternator or generator belt. If the serpentine belt has broken it will require a replacement on the site or a tow to a repair station.

Brake System Light

    The red brake system light will stay on during the application of the handbrake. If it stays on after disengaging the handbrake, it could indicate a low brake fluid level. Remember that as the brake pads or drums wear down, the fluid level will decrease in the master cylinder, so check it often. Seek assistance at a service station.

Engine Warning Light

    The engine warning light will normally be yellow in color, but might be red in some vehicles. This warning light blinks on and off during engine start. If it continues to stay on it could mean a problem with the engine monitoring system. If it flashes on and off in a steady rhythm while driving, the vehicle owner should decrease speed. Stopping and then restarting the engine might stop the problem. If the light continues to stay on, the vehicle should be taken to a repair station where a scanner tool can be used to identify the problem.

ABS Warning Light

    The yellow ABS (brake) warning light will come on briefly during engine start. If it remains on while driving it could mean a problem with the braking system, like a sensor. This warning light does not stipulate an emergency, but the vehicle owner should have it checked out by a technician who can use a code scanning tool to pinpoint the problem.

Brake System and ABS Warning Lights

    If the ABS warning light and the brake system warning light come on at the same time during driving, it means the brake condition has approached an emergency condition. If safe to do so, the vehicle owner should proceed to the nearest parking area and call for assistance. The brake pedal should not be depressed suddenly with extreme pressure during emergency pull-over.

Temperature Warning Light

    The red temperature warning light means your engine has reached a maximum temperature threshold, which could be caused by a low coolant level, failure of the radiator fan or fans, a stuck thermostat, blown head gasket or catastrophic coolant leak. The engine should be shut off immediately. Sometimes turning off the air conditioning unit and switching on the heater can cool the engine down. Regardless, extreme high engine temperatures need to be solved immediately to avoid serious engine damage.

What Is a Coil Pack?

What Is a Coil Pack?

A coil pack is a collection of coils that send a high-voltage charge to a vehicle's battery to spark the engine to start. If it is faulty, a vehicle will have power and acceleration problems.

Characteristics

    A coil pack consists of thin thread-like wires wrapped around a core unit. It is generally located on top of or underneath an engine's dust cover.

Function

    The main function of a coil pack is to increase a vehicle's electrical volt power to 35,000 or more volts. The high-voltage sets fire to the spark plug, causing fuel in the cylinder to ignite. This process initiates the start of a vehicle.

Symptoms

    If a coil pack is faulty, a vehicle may consistently lose power and shut down abruptly. Once the coil pack completely loses its voltage power, the vehicle will not start. Also, the vehicle will often idle poorly and have acceleration problems.

Senin, 16 Juli 2012

1997 Dodge Van Electric Lock Troubleshooting

1997 Dodge Van Electric Lock Troubleshooting

Dodge vans can be sold with an optional electrically operated central locking system. The sliding side-door and the tailgate are also included in the system. The system helps maintain security for cargo, and also provides safety for passenger vans because the doors can be locked while moving, and will unlock in certain accidents providing there's power. Problems with the system can be related to the keyless transmitter, locking, and unlocking. These kinds of problems can be corrected by following some troubleshooting steps.

Instructions

    1

    Change the batteries in the remote keyless entry transmitter if the doors won't lock or unlock. Remove the battery cover and install a new battery with the positive (+) icon pointing upwards. Close the cover and try the operation again.

    2

    Press the interior unlock button on the dash to unlock all of the doors if the rear doors don't unlock when you release the locks on individual front doors.

    3

    Check for an incorrectly closed door if the central locking system unlocks immediately after locking. It's an indication that a door hasn't been closed properly. Check the indicator lamps for flashing. Flashing also indicates a door on the Dodge van hasn't been closed properly.

    4

    Reprogram the automatic door lock feature if it isn't operating as required. The default is that the doors lock when the engine is started. In the case of an accident this can make it harder to be rescued, because although the locks should unlock in an accident, they won't if there's no power. Place the key in Position 2 and close all of the doors. Press the bottom of the dash central locking switch for 5 seconds. The automatic locking system will be switched off.

Problems With a Neutral Safety Switch

The neutral safety switch is a precautionary mechanism installed in all cars with automatic transmissions to prevent them from starting in any gear other than "Park" or "Neutral." This is because starting your car in "Drive" would result in the car shooting off down the road immediately after the engine turns over. If you are heading out to work and realize your car won't start and the engine doesn't make a sound, your switch may be malfunctioning. Try these steps to figure out the most likely problem.

Possible Malfunctions

    The neutral safety switch is wired to the solenoid of your car's starter. It opens when your car is in "Drive" or "Reverse" to keep the starter from becoming engaged while you are moving. The switch closes again once you have parked your car or put it in "Neutral," meaning that you can crank the starter. If the neutral safety switch becomes misaligned or stops functioning altogether, it means your car will not know whether is is parked or in gear. Therefore, the safety switch will prevent you from starting the car until it is fixed.

Testing the Switch

    You may need to test the functionality of the switch before replacing it, just to make sure that the problem is not with the car's starter. To do this, locate the switch, which is an object shaped like a steel ball that is connected to the shifter and wired to the reverse lights and the internal light. Disconnect the piece that connects all of the wires to the switch and reattach the switch to a volt-meter tester. Put the key in the ignition with the gear set to "Reverse." Do not start the engine, but look for power in the volt-meter. If there is none, the switch may be faulty or its ball bearing may have worn out and you will have to replace it.

Adjusting the Switch

    Sometimes, the switch isn't faulty at all; it has just come out of alignment with the starter. In this case, you will not have to replace the part. Simply loosen the bolts holding the switch in place and move it around. While you are moving the part around on its mount, make sure your car is in park. Try turning the ignition until you hear the engine crank. Once the engine begins to turn over, you know you have the neutral safety switch back in the right place. Screw it in, being careful not to move it, and your car will be ready to go.

Electrical Problems

    Sometimes, the neutral safety switch is not misaligned or malfunctioning, but rather, the electrical system in your car is short-circuiting. This means that the signal to the neutral safety switch is not being delivered properly. Consult your owner's manual for information on the wiring of your specific car.

Indications of a Stretched Timing Chain

Indications of a Stretched Timing Chain

A timing chain failure is your vehicle's equivalent of a massive heart attack. It can easily destroy the engine and turn your car into a smoking wreck. The timing chain turns one or more camshafts that open and close the intake and exhaust valves so it has everything to do with how well your engine runs. Timing chains last longer than belts, but they do wear out and loosen over time. Knowing what to look for can keep your vehicle off life support.

Start Up Rattle

    Timing chains are made to specifications that match their operating tension to a given application. As a chain loosens, it falls out of spec, and the symptoms begin. The first thing you will notice is a rattling sound that lasts for a few seconds when you cold-start the engine. This happens because most of the oil is still in the pan and the oil pressure is low. As the oil pressure rises and the tensioner engages, the chain tension and lubrication improve, and the rattle goes away. Even though it stops, you shouldn't ignore it as the chain will continue to wear until its guides break. This will loosen the chain some more and make the rattle louder. It might even continue when the engine warms up.

Rough Idle and Power Loss

    Since the opening and closing of the intake and exhaust valves are directly affected by the timing chain, any tension loss can cause the valves to move at the wrong time. If the intake valves open late, the pistons won't pull enough fuel and air into the chamber for good combustion. If they open early, the pistons might interfere with the engine's breathing by pushing exhaust gases out the intake manifold. Likewise, if the exhaust valves open late, the pistons won't push all the exhaust gases from the cylinders. If they open early, some of the fuel-air mixture will escape from the cylinders, and combustion will suffer. Since the timing chain also affects the distributor, ignition timing and fuel delivery, you'll notice the difference whenever you press on the gas or warm up your car.

Misfiring and Backfiring

    When the valve and ignition timing is off because of a loose timing chain, the fuel-air mixture in the cylinders ignites at the wrong time, and the engine misfires. Misfires cause incomplete combustion and higher emissions, and they leave carbon deposits on the plugs and valves. When a carbon buildup gets hot enough, it ignites the fuel-air mixture before the plugs fire and makes the engine backfire. This incomplete combustion from misfires can also leave unburned fuel in the tailpipe. Backfires that come from the exhaust are caused by this unburned fuel.

Coolant in the Oil

    When a timing chain gets so loose that it's ready to break, it rubs against its protective timing cover and wears a hole in it. You'll know this is happening because of the loud clattering noise it makes. You'll also know that you waited too long to fix it if you see coolant in your oil. Don't wait until this happens or your timing chain breaks. If you have an interference engine, where the valves can touch the pistons, and your chain snaps, you'll be replacing your engine or the car.

No Power at the Fuel Pump in My Mercedes 190

The Mercedes 190 must have power at the fuel pump when you turn the car on. Without electricity, the pump will not work; therefore, the engine will not work. The problem may be simple and easily fixed. By running some simple diagnostic tests, you may be able to correct the problem of why your fuel pump is not receiving any power.

Corroded Connectors

    Look for easy solutions first. Remember the power has to travel from the battery through a multitude of connectors to finally reach your fuel pump. Car underbodies, by nature, are constantly exposed to moisture. According to Professional Technicians at Autobahn, a Mercedes exposed to only 6 inches of water can sustain water damage to electrical components. Disconnect the battery, and clean all the electrical connectors through which the power. Use a mild solvent, such as a mixture of baking soda and water, and a toothbrush. Rinse the connections with water, and blow dry them with a hair dryer. Reconnect the battery, and test the system to see whether you have solved your problem.

Blown Fuse

    For another easy solution, look at the fuse panel and observe whether the fuel pump fuse has blown. If so, a blown fuse is a symptom of a problem but not the problem itself. You must determine why the fuse blew, which you can only do by performing a specialized test equipment. (You should have an in-depth knowledge base of auto electrical systems.) A qualified automotive electrician should be able to find the root cause of the problem. .

Broken Wire

    Wires break from time to time, and a simple broken wire will interrupt electrical flow to the fuel pump. Look at all the wires closely. If you find a broken wire, disconnect the battery and splice the wire back together. If you are not comfortable with wire splicing, refer this job to a qualified automotive technician.

Fuel Pump Relay

    The fuel pump relay may have gone bad. To test it, you will need a test light, available at any auto parts store. With the key turned on, you should have power before and after the relay. Touch the probe end of the test light to the input and output side. If you have power only at the input, bot not at the output, the relay has likely gone bad.

Minggu, 15 Juli 2012

How to Test For Leaks in a Hydraulic Brake System

How to Test For Leaks in a Hydraulic Brake System

Having your car's brakes fail is a terrifying experience, leaving you with precious few ways of bringing your car to a safe stop. Modern safety systems are designed for a warning light to come on when there is a problem with the brake fluid, but there are also a few other physical symptoms you can check for. The brakes will seem slow to react, the brake pedal will feel mushy and there may be hydraulic fluid leaking under the car. Checking for where the leak is coming from is quite simple, but fixing the problem can be rather expensive.

Instructions

    1

    Park your car in a safe place and lift up the hood of the car.

    2

    Check the hydraulic fluid levels in the master cylinder near the firewall of the car. There should be a maximum and a minimum level marked on it. If it is below the minimum you have a leak somewhere in the car, if not there is a problem with the brakes themselves.

    3

    Examine around the cylinder and surrounding components for signs of fluid leaking from the cylinder itself.

    4

    Check the metal lines running from the cylinder to each brake for any oily liquids on the line or dripping underneath the car. Repeat this for all four brakes.

    5

    Pay special attention to the rubber hoses and connectors where the metal brake line joins the brake system. This is the most common place to find leaks.

How to Troubleshoot a 1994 Jeep Wrangler With Oil in the Air Filter

How to Troubleshoot a 1994 Jeep Wrangler With Oil in the Air Filter

Troubleshooting oil in the air filter of a 1994 Jeep Wrangler fortunately is a relatively easy task. There are a few reasons oil might be in the air filter, so narrowing down the cause should not take much time or trouble. Repairs for oil in the air filter can range from easy and inexpensive to challenging and expensive. You can diagnose the cause yourself, but you may have to get a qualified mechanic to make the repairs.

Instructions

    1

    Look carefully at the air filter to determine exactly where the oil is located. Check to see if the oil is on one side, on the outside only or on the inside of the filter.

    2

    Replace your PCV valve. The PCV valve works within the emission system of your Jeep and if it's clogged or broken it will cause oil to be in your air filter. Trouble with the PCV valve will be indicated by oil on the outside of the air filter.

    3

    Look to see if the there is any oil on the inside of your Jeep's air filter. If there is, more than likely you have a more serious engine problem, such as worn rings or blown pistons. These repairs will need to be performed by a certified mechanic.

How to Tell if the Clutch or the AC Compressor Is Bad

How to Tell if the Clutch or the AC Compressor Is Bad

The air conditioning system on a vehicle has a number of components that work in concert with each other to deliver cool air to the passenger cabin. The clutch drives the compressor, which sends refrigerant to the evaporator where refrigerant gets condensed. The refrigerant travels though the lines and is cooled by the radiator. Cool air gets blown through the air conditioning vents in the passenger compartment. If one or a few of these system components fails, cool air cannot be produced. Checking the air conditioning clutch and compressor requires a few steps, gauges and hand tools.

Instructions

    1

    Shift the vehicle into neutral or park. Engage the emergency brake. Raise the hood. Touch the positive lead of a voltmeter to the positive battery terminal. Touch the negative lead of the voltmeter to the negative battery terminal. Turn the voltmeter gauge scale to volts and read the number. If the battery voltage reads below 12.5 volts, the compressor will not turn on. Charge the battery. If you still get a low reading, the battery has a shorted cell and must be replaced.

    2

    Start the engine and let it warm up. Stand in front of the AC compressor at the front of the engine. Have an assistant turn on the AC controls to maximum. Wait for the AC clutch in front of the compressor body to engage and spin. If it does not, shut the engine off and disconnect the negative battery cable with a socket.

    3

    Locate the main fuse box. Pull out the AC fuse and examine the filament inside the fuse. Replace the fuse if the filament has melted or blown apart. Look for the AC relay in the fuse box. Swap it with another relay that has the same amperage and pin configuration. Connect the negative battery cable with the socket. Start the engine and have your assistant turn on the AC controls to maximum. If the clutch engages, the fuse or relay was at fault.

    4

    Determine if your vehicle uses R12 or R134a refrigerant. For the R12, hook up the low-side hose of an AC gauge to the low-side nipple on the compressor. The low-side will have a 7/16-inch screw-on fitting. Connect the high-side hose of the gauge to the high-side compressor nipple, which will be a 3/8-inch screw-on fitting. For the R134a type refrigerant, push the high-side gauge hose onto the quick release 16 mm nipple on the compressor. Push the low-side gauge hose onto the quick release 13 mm nipple on the compressor.

    5

    Start the engine and turn the AC controls on maximum. Open the high- and low-side knobs on the gauge. Look at the reading. The low-side reading should indicate between 25 and 40 pounds per square inch (PSI). The high-side reading should fall between 200 and 225 PSI. If it reads outside of these limits or shows no charge at all, the cutout relay inside the compressor is preventing voltage from activating the clutch. Charge the AC fully with the correct refrigerant.

    6

    Inspect the clutch pulley belt with the engine turned off. The belt should have no cracks or oil contamination that would cause it to slip. If it slips, the pulley will not attain sufficient revolutions to engage the clutch mechanism. Check the belt for the proper tension. No more than 1/4-inch of free-play should be allowed. Loosen the bottom AC compressor mount bolts and the top adjusting bolt with a socket. Pull the compressor against the belt to remove excess slack, then tighten the bottom and top compressor bolts.

    7

    Place a mechanic's stethoscope probe on the top of the non-moving part of the clutch while the engine idles. Have your assistant turn on the AC controls to maximum. Listen for any internal buzzing or clicking from the clutch. If the clutch fails to engage and spin, but you hear electrical buzzing or clicks inside, it indicates an internal clutch short. Listen for excessive bearing noise coming from the clutch or compressor. Worn shaft bearings will build up resistance in the wiring and fail to turn on the clutch. Clutch pulley wobble also indicates worn shaft bearings.

    8

    Shut the engine off. Loosen and remove the three bolts that hold the circular faceplate to the outside of the clutch. Pull the plate off and look at the end of the shaft bearing seal on the clutch. If you see any oil residue, oil film or obvious leakage, it means the compressor shaft seal has failed and discharged refrigerant from the system. You must replace the shaft seal and recharge the system.

    9

    Disconnect the wire connector on the clutch with the engine off. Clean the contacts on both wire connector sides with electrical contact spray and a cotton swab. Start the engine and turn the AC controls on maximum. Have your assistant hold a jumper wire on the positive battery terminal while you touch the wire to the "hot" wire inside the wire connector (on the clutch side). If the clutch fails to engage, it means the clutch has an internal short.

Sabtu, 14 Juli 2012

How to Tell If Valve Seals or Valve Guides Have Gone Bad

How to Tell If Valve Seals or Valve Guides Have Gone Bad

Valve problems are a sign of serious issues with your car or truck's engine. Properly sealed valves are crucial to your engine's compression. A problem with the valve seals or guides will mean that you will have to completely rebuild your vehicle's motor in order to restore it to good working condition. If you believe your vehicle is having valve problems, you should take it to a certified professional mechanic and have it thoroughly evaluated.

Instructions

    1

    Open the hood and check your oil. If there is too much clearance between the valve guide and the valve stem, it will cause the engine to consume oil. If the oil is continuously running low regardless of how often you are adding it, and you have not noticed any areas where oil appears to be leaking out of your engine, there is a chance that your valve seals and guides are failing.

    2

    Start your car. Watch the tail pipe for exhaust. If an excessive amount of exhaust is coming out the tailpipe and it is thick and bluish or gray in color, it is being caused by burning oil. This is where the oil your vehicle is consuming is going.

    3

    Listen to your car running. If you can hear a tapping or rattling noise coming from within the engine, there is a good chance the noise is coming from the valves. Valve noise stems from problems within the engine and with the valves themselves.

    4

    Determine if your check engine light is on. If it is, hook your car up to an OBD II error code diagnostic reader to the vehicle's powertrain control module and scan the PCM for error codes. Problems with your vehicle's valve seals or guides will come up under specific code numbers. Codes P0075 through P0086 are generic exhaust valve codes (see resources) and brand specific valve codes can be determined by looking up the codes using the make of the vehicle (see resources). These will give you a good idea of where to start looking for your valve problem.

    5

    Disassemble your engine and manually inspect the valves, valve seals and guides. This is a complicated process that should not be attempted by anyone who is not a certified mechanic because taking an engine apart incorrectly can severely damage the components. Also, you have to understand what your valve seals and guides should look like in good condition in order to determine if there is a problem with them. You should look for areas that appear dented, damaged, burned or to be leaking an excessive amount of oil.

Jumat, 13 Juli 2012

What Causes Rapid Ground Electrode Wear on Spark Plugs?

Spark plugs are fairly simple devices, a controlled electrical short in the same sense that a carburetor is a metered fuel leak. Spark plugs operate in some of the most Faustian conditions on Earth, constantly subjected to thousands of degrees Fahrenheit, corrosive chemicals and a maelstrom of mechanical pressures. Ground strap erosion isn't the most common plug failure, but it's common enough to warrant some diagnosis.

Detonation and Preignition

    Uncontrolled fuel detonation comes first on this list, primarily because it'll destroy everything in your engine, starting with the plugs. Detonation -- aka knock or ping -- is the result of abnormal combustion in the cylinder, often itself the result of fuel detonating on its own somewhere in the cylinder. If you're lucky, detonation will eat the plugs before it destroys something considerably more expensive. Detonation and preignition are two subtly different things, and exhibit different symptoms on the plug. Detonation as the result of a lean air/fuel ratio, ignition advance or low-octane fuel will typically crack the ceramic insulator. Preignition causes the ground strap to melt and shorten.

Corrosion

    Corrosive chemicals in fuel and oil might not do much at room temperature, but they'll eat a plug electrode as though it were immersed in saltwater. Oxygen is the primary culprit here, for a few reasons. Extra oxygen in the cylinder will, on its own, oxidize the plug faster simply because it's operating in an oxygen-rich environment. Secondly, a lean fuel mixture increases the odds of detonation, and it always makes the plug run hotter.

Overheating

    Spark plugs have a "heat range," determined primarily by the size of the insulator on the tip. A "colder" range plug is one which conducts more heat away from the tip, thus reducing stress on the plug and the likelihood of heat-induced damage. Modern cars generally use a "hotter" plug, which will, within limits, enhance combustion efficiency, fuel economy and emissions performance. Engines using superchargers, turbos, nitrous oxide and extremely lean air-fuel ratios demand a colder heat-range plug. On most overheating cases, the ground strap won't shorten so as much as it will become very thin and brittle.

Lead Errosion

    The copper alloy used in modern plugs doesn't get along too well with lead; in fact, additives containing lead can quickly erode a ground strap down to the nub in a very short period of time. The lead essentially soaks into the copper's crystalline matrix, causing it to fall apart the way that rainwater causes sinkholes to form. Compounding this is the fact that lead additives are favored primarily by racers and performance enthusiasts, who are likely already running higher cylinder pressures through any number of performance mods. Look for a bile-yellow deposit on the normally white ceramic insulator -- a sure sign of lead fouling.

Kamis, 12 Juli 2012

My Geo Tracker 4WD Won't Disengage

My Geo Tracker 4WD Won't Disengage

The 4-wheel drive Geo Tracker is known for its fuel efficiency. However, sometimes components like the hubs can lock up, robbing the vehicle of fuel economy and potentially burning up the transfer case. Yearly maintenance of the drivetrain prevents such damage and extends the life of your truck. Grease and test the hubs, check that the drive shaft and U-joints are tight, and make sure the transfer case shifts smoothly. Repair any worn or seized components as soon as possible to avoid further damage.

Instructions

    1

    Shift the Tracker into 2-wheel drive while the engine is running and the vehicle is in park. Do this in a clear area such as a long driveway or empty parking lot. If it will not shift into 2-wheel drive, then the transfer case is seized or worn and needs to be serviced. Otherwise, drive straight in reverse for at least 10 feet. This should unlock the hubs.

    2

    Lift the truck off of all four wheels simultaneously with jack stands or a lift, while it is still set in 2-wheel drive. Turn on the truck. Shift into DRIVE and allow it to idle. Climb out, keeping clear of the wheels. If the front wheels are spinning, then the hubs are seized in the lock position and the transfer case is locked in 4-wheel drive. Both will need to be repaired. Otherwise, refer to the next step.

    3

    Put the Tracker into park. Engage the parking brake and turn off the engine. Remove the front hubs. Disengage the parking brake, start the engine, and shift into drive. Check the splines in the center of each front wheel. If they are spinning, then the hubs are working properly but the transfer case is stuck in 4-wheel drive and needs to be serviced. Otherwise, continue on to the next step.

    4

    Hold the brake, shift the transmission into neutral, and set the transfer-case into 4-wheel drive. Shift the transmission into drive and release the brake. Check again to see if the splines in the center of the front wheels are spinning. If not, you need to repair the front axle side of the transfer case. Otherwise, put the truck into park, set the parking brake, and shut off the engine, leaving it in 4-wheel drive.

    5

    Grease the inner spline of the front hubs lightly, using gloved fingers. You might need to replace the O-ring or gasket. Reinstall the front hubs. Release the parking brake, turn on the engine, and shift the transmission into drive. If all four wheels are spinning, then the hubs lock properly.

    6

    Apply the brakes. Set the transfer-case into 2-wheel drive, shift the transmission into reverse, and release the brakes. Check that the rear wheels are spinning and the front wheels are still. Turn a front tire using your hands, keeping clear of moving parts. If it will not turn with moderate force, your hubs are frozen and need to be serviced. Otherwise, shift the transmission into park, turn off the engine and lower the truck back onto the ground.

How to Test the Crank Sensor on a 1990 Silverado

The 1990 Silverado does not have a crank sensor behind the balancer. It hadn't been developed for Chevy trucks yet. All the engine options, the 4.3-, 5.0-, 5.7- and the 7.4-liter engines, use the same distributor that houses a pickup coil. This pickup coil is the predecessor to the crank sensor and serves the same purpose. The pickup coil is found under the rotor in the distributor and uses the teeth on the distributor shaft as the reluctor. As the distributor turns, the pickup coil provides a 4X-AC voltage signal to the module for ignition control while cranking. The ICM passes this 4X-signal to the powertrain control module. The PCM sends this signal back to the ICM for timing control.

Instructions

    1

    Check the battery for a full charge. Place the red voltmeter lead on the positive terminal and the black lead on the negative terminal. Fully charged, the battery shows between 12.5 to 12.75 volts. If the battery displays less voltage, charge it before proceeding or the tests will be inaccurate.

    2

    Locate the distributor mounted in the rear of the intake manifold. Notice the ignition control module attached to the distributor base with two bolts. It has three electrical plugs: a black two-wire and a four-wire situated side by side, and a white connector facing the opposite direction on the right rear of the module. The front, black two-wire is for the pickup, and the other is for for the ICM. The white two-wire plug is the one you test first. It is the input to the ICM.

    3

    Pull the white two-wire connector off the module. Straighten out the two paper clips and place one in each of the two female terminals in the module where the connector was removed. Connect the two voltmeter leads to the paper clips in any order. Polarity is no issue on this test.

    4

    Place the voltmeter on the low alternating current scale. Crank the engine and observe the voltage. If the pickup coil is good, it fluctuates between 0.3 to 1.8 volts AC. Turn off the key.

    5

    Set the voltmeter to the ohms scale to test the pickup coil for the proper resistance. Leave the voltmeter probes in the same location. There must be between 500 to 1,500 ohms. If the pickup coil fails either of these tests, replace it. Remove the paper clips and install the connector into the module.

    6

    Check the ICM to ensure it is sending a signal to the computer and receiving one in return to control the timing. The coil has two connectors. Connect the red voltmeter lead with an easy clip to either of the pink wires on the coil electrical connector. Place the black lead on the battery negative or ground terminal.

    7

    Turn the key on. There must be 12-plus volts or battery voltage. This means the ICM also has battery voltage since they are on the same circuit. If the voltage is lower than the battery voltage or has no voltage, check the wiring to locate the open or short. Remove the voltmeter.

    8

    Connect the circuit tester alligator clip to the positive terminal on the battery and probe one of the white wires on the coil connector. Have a helper crank the engine. The light must flash on and off rapidly, indicating the ICM is functioning. If the circuit tester does not flash, the ICM failed. This is quite common with this type of ignition system.

How to Check the Injectors on a 4Runner

How to Check the Injectors on a 4Runner

The Toyota 4Runner was introduced in 1984, but it was not equipped with a fuel-injected engine until 1985. The electronically fuel-injected engines have high-pressure fuel lines feeding electronically controlled fuel injectors. When the fuel injector receives an electrical pulse, the solenoid charges, briefly opening a valve inside the fuel injector. The opened valve allows pressurized fuel to flow through the injector, out the nozzles and into the combustion chamber where it is ignited by the spark plug.

Instructions

ODB-II Reader

    1

    Locate the ODB-II port under the driver's side dash, if equipped. The scan port is generally on the far left hand side just above the kick plate under the dash cover.

    2

    Connect an OBD-II reader to the scan port. Turn the vehicle to the "ON" position. It is not necessary to start the engine.

    3

    Turn on the scan tool and follow the on-screen instructions to read the engine codes.

    4

    Decode the displayed codes by comparing them with the scan tool manual's decoder. Engine diagnostics may detect failed injectors or conditions that indicate possible failure. Common codes showing lean or rich conditions in a given cylinder indicate the need to check the injectors on the associated cylinder.

Fuel Injector Plug Voltage

    5

    Open the hood of the 4Runner.

    6

    Disconnect the fuel injector electrical plug from the injector to be tested.

    7

    Set the multimeter to measure voltage. Connect the red multimeter lead to the electrical plug. Connect the black multimeter lead to the negative terminal on the battery.

    8

    Turn the ignition key to the "Start" position, but do not start the engine.

    9

    Read the multimeter voltage readout. The readout should indicate approximately 12 volts of electricity being passed through the plug. Check all the leads if necessary. If the plug leads have failed, have the engine control module tested.

Fuel Injector Resistance

    10

    Disconnect all of the 4Runner's fuel injector plugs from the respective injectors.

    11

    Set the multimeter to display "Ohm." The Ohm measurement may be indicated by an Omega symbol, which looks like an upside-down horseshoe. Touch both the red and black leads, from the multimeter, to a single fuel injector's terminals. There will be two terminal plugs to which the leads must touch. Either of the leads may touch either side of the terminal as long as both terminals are used.

    12

    Write down the Ohm measurement for the fuel injector, as well as the injector position on the engine.

    13

    Repeat steps 2 and 3 for all remaining fuel injectors.

    14

    Compare the Ohm measurements. Any measurement that is substantially higher or lower indicates the resistance of that particular fuel injector is not in line with other injectors. Resistance that is too high or too low indicates a failed injector. Replace the injector.

Fuel Injector Operation

    15

    Start the engine.

    16

    Press the metal end of a screwdriver to the top of the fuel injector.

    17

    Hold your ear to the handle of the screwdriver. Listen for a clicking noise. The clicking noise indicates the solenoid is charging and opening the valve. Failure to produce a clicking noise indicates possible injector failure.