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Misfire Troubleshooting: The Tutorials
OK, so you've found the dead cylinder. What's next? -you might be asking yourself. Well, the next step is to find out what's causing the misfire (miss) condition.
There are several possibilities:
- Ignition system problem. For example:
- Bad ignition coil pack.
- Bad spark plug.
- Bad spark plug wire.
- Bad ignition control module.
- Fuel system problem. For example:
- Bad fuel injector.
- Fuel injector not being activate by PCM or due to a short in the wiring.
- Engine Mechanical. For example:
- Low engine compression.
The above list may seem like troubleshooting a ‘dead’ (misfiring) cylinders is hard but with a good diagnostic strategy, you'll be able to find the root cause of the misfire.
Here are my suggestions (and the diagnostic strategy I use):
- Test the ignition system first.
- The ignition system is usually the culprit behind most of the misfire (‘dead’ cylinder) conditions.
- You can find an in-depth tutorial on how to test the ignition coil packs and spark plug wires here: GM 3.8L Ignition Coil Pack Tests (at: easyautodiagnostics.com).
- Test the fuel injectors second.
- After eliminating the ignition system as the cause of the misfire, the next step is to make sure that the fuel injector is not fried internally.
- You can find an in-depth tutorial on how to do a fuel injector resistance test here: How To Test The Fuel Injectors (GM 3.8L).
- Test the engine compression third.
- After making sure that the ignition system is providing spark and the fuel injector is injecting fuel into the ‘dead’ cylinder, the next step would be to check that cylinder's compression.
- You can find an in-depth tutorial on how to test the ignition coil packs and spark plug wires here: How To Do An Engine Compression Test (GM 3.8L).
The above list of tests can be modified to suit your particular diagnostic, troubleshooting needs (since there really isn't a specific cookie cutter way of diagnosing a car).
If this info saved the day, buy me a beer!
