misfire logging

[PLohr]

Hello,
I am chasing a cold start misfire on a 2008 GMC Yukon XL (6.2L). I am logging the typical parameters and the current misfire PIDs (MFCYL1C through MFCYL8C). I could be doing something wrong since the MFCYL*C PIDs are getting values of zero. I am using V8 software and a FlashScan V2. A couple of log files are attached. Thank you for any help.

[PLohr]

Good morning, folks. Still chasing this issue.

I found the quote below on the Snap-on scanner forum, which may be relevant to why I'm not seeing non-zero values for MFCYL*C PIDs:

"Look for the pid called "Cycles Of Misfire Data". It should be counting up from 0-99 and then start the cycle again. If the value doesn't increase, the PCM will not recognize misfires, even if it only runs on a single cylinder."

Credit for the above is given to the user Orevin on the Snap-on forum.

Entire thread is linked here:
http://askatech.autorepairdata.com/forum/showthread.php?t=11072

Still chasing... :)

[joecar]

The PCM has conditions for looking at (and counting), and for ignoring misfires (and not counting)... seems like the is the latter situation.

Thanks for posting (I'm learning all the time) :cheers: