16197427, $0D, AMC/Jeep 401 MPFI.
Ok, so lately I have been getting some random backfiring out the exhaust when decelerating (DFCO) It started out a few months ago and has been getting worse. I can not remember exactly when it started and what/if any changes I made to the bin when it started. I dont remember because it started out weakly, just every once in a while, then it would only do it when cooler, and stop once it was fully warmed up. Now its doing it all the time.
I couldnt figure it out, why it was doing this in DFCO. Only thing I could think was fuel had to be getting into the engine in DFCO. I was fearing a leaky injector. But before that I decided to do a data log, and low and behold, AE was pulsing rapidly when in DFCO!?!?! You can see it going on-off-on-off and the injector BPW going from 0 to 1.69 and back to 0 as the AE pulses. I am at a loss of what could be causing this. Should it not be disabled in DFCO?
Only thing I have been making any change to is TPS AE and a little to the MAP AE. With it doing it more when not fully warmed up, I thought maybe it was a MAT/AE correction issue, so I disabled it in the bin and set all the MAT parameters back to what it was stock in the bin (no IAT from the factory in this bin) This did not make a difference. I have tried changing the 0 TPS cell in the TPS AE table to 0 and lowering the lower TPS values a bit. This did not help either.
I have changed the AE settings in this bin as it has never been enough. For the life of me I can not get the AE to be right. It seems like the more I raise it, the better it does and no more lean spike if I hit the gas, but if I blip the throttle at idle it almost floods it. The backfiring seems to get worse too. AE has been the one thing since day one on this conversion that I have not been able to sort out. Its driving me nuts.
Anyone have any idea why it would be pulsing in DFCO?
Attached is a copy of my bin and a short data log showing the issue.
Reply With Quote
Bookmarks