Your customer has a car with a misfire problem and it should be fairly simple to diagnose and repair. But once you start correcting issues, you’re not getting closer to a fix. SureTrack community member Taddia78 had a Honda Odyssey in their shop that had a misfire soon after starting. They posed the question to the community, and with the help of fellow community member JimA, DAG1365 and others, they were able to resolve the issue quickly.
The following Community Fix summarizes the interaction between members of the community that led to the solution.
Vehicle
2011 Honda Odyssey EX-L 3.5L
Title
Flashing CEL, P0300, P0302, P0306, Performed CKP Relearn.
Complaint
Customer states the vehicle runs smooth when first started but then starts misfiring after 20-30 seconds.
Diagnostic Steps Performed/Parts Replaced
Replaced timing belt, and rechecked timing. Adjusted valves as all valves were way out of adjustment. Replaced spark plugs and ignition coils. Swapped new ignition coils and plugs, no change in misfire. Performed compression test and all cylinders were +/- 180 psi. Ran compression test and all cylinders were 0 – 30 psi. Removed and tested fuel injectors and all injectors operating and spraying properly. NOID light used to test for PCM signal and all good. MAF sensor reading 4.8. MAP sensor PID reads 10 in/Hg, Vacuum gauge reading 18 in/Hg.
Cause
After a lot of reading and circuit testing, the PCM was commanding the Fuel Injectors for cylinders #2 and #6 off after several seconds of operation. Due to the horrible misfire and arcing caused by Cylinder #2 the PCM went into a “safe mode” shutting off the fuel injectors to keep from damaging the converter. After replacing the plugs and coils the PCM never came out of “safe mode” and although everything was now fine it continued to shut off the fuel injectors causing the misfire after a few seconds of smooth operation. To confirm this theory I disconnected the crank sensor and started the engine, the misfire did not return after several minutes.
Correction
Reconnected the crank sensor, cleared the CKP memory, and performed a CKP relearn. Everything is still running fine.
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