I just got done putting my motor back together for the millionth time. I had an issue of the intake manifold not sealing to the heads. Anyway,

My old symptoms were O2's showing an extremely rich fuel mixture. Datamaster was showing both fuel trims going to the full rich end, I.E. car leaning out as much as possible. I had really low vacuum, extremely nasty stumbling with moderate to quick tip-in throttle movement, and a generally rough running car. My O2's were staying pegged in the 800-950 range. All this due to oil and vapors making their way in to the intake runners.

After running the car tonight, it was still running rough, but my fuel trims were both FULL LEAN. The cam is a mid 230's low 240's Joe O cam (read TIGHT LSA) and as the car was running like it was really rich (stumbling still, puffing black smoke, running rough, low vacuum) the fuel trims were saying otherwise, and the O2's were bouncing from the 800's down to the 100's and back, unlike before. I was getting an idle surge from the commanded 950 up to about 1350 and back, but it wasn't ANYTHING like it was before.

Could this simply be a case of bad reversion??? I can email the datamaster log upon request, be advised that it's for the DA version.

 

please send me the datamaster file.

sounds like overlap.

i know you said it changed to full lean trying to pull fuel after you tuned it. butafter you cranked the car, was stumbling and back firing when it was in open loop or did it just start when it went in to closed loop. i have a joe o cam thats in 24x/24x on a 107. so i will be asking for help soon.

but send the the file please. and i give my opinion, whatever thats worst