I spent a few hours doing some VVE tuning on a friend's truck today (2012 Silverado BTR Truck Norris cam only) and made some solid headway, but noticed that the lower load cells and the idle area didn't seem to change much at all after 4 rounds of logging/tuning. I used STFT to tune today and obviously made sure to stay away from PE and tuned drivability areas only. The following steps were taken:
-Disabled MAF by lowering frequency to 2hz and set P0103 to MIL on 1st error
-Disabled LTFT and closed loop enable by maxing out temps
-Disable COT and DFCO
Trims started off super fat in the 16-26% rich range across the board. Again, after 4 rounds of tuning I could see noticeable improvement in all areas of the histogram I created except for the very low load areas and idle range some. They came down a hair at best but essentially remain 15-20% rich in all areas I've described. When I copied and pasted the histogram each time I pasted Multiply by % half to make incremental adjustments.
My question is am I missing something. Is the ECU controlling fuel in another manner in these areas not allowing the changes I'm making to take hold? Any help would be greatly appreciated. Novice at this.
PS- After today's VVE tuning and last week's MAF tuning the truck runs 10x better. All idle surging issues, RPM dropping too quickly after a rev, etc. have been completely resolved.