A: The grounding test is performed to determine if a plug is firing. You want to watch the center electrode to see if a strong, blue spark is created. Alternatively, you can use a spark plug light.

Use a spark tester to check the ignition coil. Plug the tester into the coil. Attach the ground wire. Plug in the coil connector. Adjust the spark gap to the correct measurement. Start the engine.

Though small, spark plugs play an important role in getting your vehicle started and keeping it running—so when they’re past their prime, you’re going to want to replace them.

In this video, I show you how to test spark plugs and coils on any car, even if the spark plugs are recessed or hard to reach. Whether you're troubleshooting engine misfires, poor performance, or ...

In this video, I’ll show you exactly how to test your BMW spark plugs, ignition coils, and coil wiring without needing a multimeter—just using the kit provided. Whether it’s a misfire, bad ...