LTFT off by -10 after autove and maf tuning

[Gregs]

after getting my ve and maf tables perfect i went back to closed loop and now my fuel trims are consistently in the -10 range. i'm not sure what i've messed up. I do have B3601 set at 14.12 because i use E10. I'm thinking maybe that has something to do with this problem. Any ideas?

[Chevy366]

14.12 is kind of a misnomer , you get more than likely a 6 to 7% blend at most stations , so 14.32 is more accurate .
14.32 is middle of the road so if you run E0 (zero) or E10 it performs good either way , so I hear .

[WeathermanShawn]

If you see the problem exist and you are still MAF-Enabled (Closed-Loop), just apply your LTFT correction against your MAF Frequency (per CALC.VE Table)..see signature for Tutorial.

Once you are back to closed-loop, it is almost entirely the MAF dictating Trims (steady-state airflow). [..I have done a lot of testing on VE, MAF and Trims..] What you are describing is not uncommon. Open-Loop tuning where each airflow model is separated, does not always interact the same when combined in a SD/MAF Hybrid utilizing closed-loop. You can debate it all day, but your experience is quite common.

Personally, I keep B3601 at 14.629. I understand the E10 debate, but knowing the ethanol or oxygenate content of each sample of gas seems mind-boggling. If one initially models for a sample AFR, and Trims stay sane..it just seems like a lot of circular tuning with a lot of unknowns.

Try adjusting the MAF using LTFTBENS. It works well in closed-loop..

[Chevy366]

Use Stoich to tune with then plug in the E10 value , should see -3,-4 % is normal .