Spark discharge is one of the most common methods of checking your car's ignition. You can visually check to see if your engine is producing a charge by removing the spark plug cover and cranking the engine. If you see a spark discharged from the end of the wire, you can rule out ignition problems when your car is missing or won't start at all. This technique has been used for years, and even experience mechanics will check it before moving on to other more complicated diagnosis.
Lean over the hood of the car while the engine is off and pull off the nearest spark plug wire with your fingers. Remove the spark plug with a spark plug socket.2
Place the end of the spark plug back into the spark plug wire just as if it was before you removed it. Put on a pair of leather gloves.3
Hold the spark plug with your fingers by the thick rubber portion at the end of the wire.4
Instruct an assistant to sit in the driver's seat and turn the key to turn over the engine briefly. If the engine starts, that's okay. Observe the end of the spark plug. If it discharges a consistent spark, the ignition is fine. If you don't see any spark, you could have a problem with the ignition system.