Hi all - Has anybody seen a repeatable misfire at low rpm, low boost with injector pulse width spikes? It seems I have some sort of misfire going on when my truck is in the 2000rpm range and I get creeping into boost (2-3psi). If feels like a thump in the drive train when this happens. I see lean spikes in both O2's, as well as the WB in the drivers side header, which leads me to believe misfire. The interesting thing is I sometimes see quite a large spike in the injector pulse width. Could this be causing a misfire? I don't see any MAF, MAP, voltage spikes, etc. corresponding to the IPW abnormality. Who's telling the injector to spike pulse width????
The other thing I noticed is this occurs right at 2-3 seconds after going into PE. Is there a 2-3 second clock for anything in the tune that might cause this?
Before you ask, I was running TR6 plugs, original gap ~0.040. After I noticed the misfire, I figured it was spark blowout. So, I swapped in some BF7EF's with out of the box gap ~0.028". The problem is still there, maybe a little better. but not fixed. After changing plugs, I stayed on the throttle after a misfire and it cleared right up and ran smooth. It may have done this with the old plugs but I always let off.
The attached log is after changing to BR7EF's. You can see it happens three times, circled in red. The third time you can really see the IPW act up.
Low Boost Misfire.JPG
2007 Silverado NNBS 6.0L L76 E38, TVS 1900, Kooks headers
Thanks!