2003 Silverado Going lean?

[kostelacd69]

Tuning my 2003 2500 6.0l with a non intercooled Whipple at about 5 lbs. Tuning was going fine until I saw a horrible lean spot around 2200-2600 rpm at about half throttle. The commanded AFR is staying correct but you can see the duty cycle fall off making it lean. What did I miss? WOT is fine everytime.2004120042

[kostelacd69]

Frame 300

[kostelacd69]

Also frame 400 and 910

[kostelacd69]

Found it! MAF Test c2911 was too low causing the computer to force it back to the 1 bar MAP sensor

[joecar]

Found it! MAF Test c2911 was too low causing the computer to force it back to the 1 bar MAP sensorGood job in finding it :cheers:

this means your VE table is not correct at that cell.

[kostelacd69]

When tuning it on VE only the MAP stops at 103, so i tried to get it as close as possible with out exceeding 105. I am assuming that when in boost the MAP stops at 103kpa and the metter keeps going making the different between the two very large, is that not correct? Also I did not get any codes.