What causes a cylinder to have a misfire?
A misfire (or dead cylinder) is usually caused by a problem in the ignition system. Specifically, a lack of spark reaching the spark plug but not always. Let’s take a brief look at the different things that can cause a misfire:
What is the diagnostic code for an engine misfire?
When the check engine light illuminates, your car’s primary computer, which is often referred to as the powertrain control module (PCM), will store a diagnostic trouble code (DTC) in its memory. Codes P0300 to P0312 are the primary DTCs associated with an engine misfire.
How to troubleshoot misfire codes on GM 3.1L mini-van?
Testing a misfire condition or misfire codes (P0300, P0301, P0302, P0303, P0304, P0305, P0306) on a 3.1L or 3.4L V6 Gm car or mini-van can seem like a really difficult task. You could be asking yourself questions like: Where do I Start?
How does a bad ICM cause a misfire?
Bad ignition control module (ICM). The ignition module usually fails in one of two ways: It either stops activating all of the 3 ignition coils sitting on top of it or it stops activating 1 of the 3. Having one ignition coil not creating spark will cause a misfire condition. Bad spark plug.
How to troubleshoot a hard to diagnose misfire case?
Identifying the misfiring cylinder is the very first thing that has to be done to successfully find the exact cause of the misfire. In an OBD II equipped vehicle, like my brother-in-law’s Monte Carlo, this involves checking for diagnostic trouble codes.
Why is my PCM not registering a misfire code?
And the catalytic converter wasn’t the source of the misfire. It’s not rare for a PCM not to register a misfire code when there’s an actual misfire condition affecting the engine, I have seen this a lot, so not having a specific misfire diagnostic trouble code (DTC) didn’t surprise.
What causes a vacuum leak to cause a misfire?
Or something causing a lean condition (like a vacuum leak). My brother-in-law suspected that one of the ignition coil packs could be bad and since most misfire conditions tend to have their root cause in the ignition system, my next step was to test for spark.
Can a 2000 Chevy Monte Carlo be misfired?
This is a real life case study that will help you diagnose a hard to find misfire. Although this case study involves a 2000 Chevy Monte Carlo (with a 3.4L V6), you can apply this info to any 3.1L or 3.4L GM equipped vehicle (see the Applies To box on the second column).