MAF calibration

[obthomas]

There is an old saying that If you don't know where you are going any way you go will get you there.
I want to calibrate my MAF and need to know where I am going. I have a Frankenstein engine that is running but probably needs a MAF calibration. Here is where I think I am going:

1. prevent closed loop operation
2. prevent switch to speed density
3. shut down all fueling adjustments
4. insure AFR command is correct
5. drive and log MAF frequency
6. add or subtract log values in HZ from MAF calibration table
7. Repeat until log values are small.
8. Restore everything that was disabled.

What I think may be happening is this process forces the ECU to a base MAF value for the commanded AFR and that base value is what I want in my MAF table.

I really appreciate anyone that will take the time to help me understand what I'm doing. Thanks

[edcmat-l1]

No. Use the trims to dial in the MAF and/or VE/VVE. Forget everything you've read about open loop tuning.

[obthomas]

O.K. .............So my fuel trims are adding up to a little more than minus ten in the idle to 2000 rpm area. If I reduce the MAF HZ in that range will the ECU see less air and reduce the fuel? Is that how I use the trims to dial in the MAF?

[LS ROB]

Correct. If you have -10 on trims in the idle cell when idling, you would copy that number from the idle cell in the scanner, then paste % half into the MAF table in editor.

[JayRolla]

Correct. If you have -10 on trims in the idle cell when idling, you would copy that number from the idle cell in the scanner, then paste % half into the MAF table in editor.

Setup a histogram for STFT sensor percent vs MAF hz and copy paste multiply by 1/2 those numbers into the curve. Then tune WOT with MAF AFR error. Disable LTFTS.