Tuning Protocol

[GRX]

Is it better do disable closed loop operation while tuning (with a AFR meter); and then when you've got it "right", then switch on closed loop (so that BLMs are close)? TIA [Modified by GRX, 12:00 PM 2/16/2004]

[GRX]

ttt

[ZD1]

Is it better do disable closed loop operation while tuning; and then when you've got it "right", then switch on closed loop? TIA

I would agree with you if you are close. If your not close (big cam/big changes) I would leave BLM and Short term guys alone-the point will be to get it within +/-15%.

I actually went through a stage where I only allowed the ECM to add fuel (but not take any away). Starting with a WB and datamaster took fuel fuel away until the car went into closed loop. This got me within 5 to 10%.

Then I completely disengaged the BLM and Short Term. Unfortunately my car seems to run better without ECM help than with. Depending on the day, it got me within 5%.

Random note:
1) If anything, I'd disable the the AFR% adjustment for Open loop (I set mine th 2% except at 90/100 load where it is 13%/14%

2) As difficult as it may seem...only change 1 thing at a time. This is especially true for the idle as about 6 differect tables effect it.

3) adjust timing OR VE tables, not both

4) Take notes of what VE generated what AFR

[GRX]

Gosh, I wish I could compare with what you sais except that my 85 has limited tables to tune with unlike later years. I don't have a VE table as an example. :sad:

[ZD1]

You gotta have something that relates to load (MAF or MAP) vs RPM. The only other way to meter fuel is alpha-N (throttle position only) or wide band closed loop.

[GRX]

The only table close enough is "Injector Pulse Width Vs. Load Value".