CORV3TT3

I have a pretty good idle in closed loop. I've adjusted the gains and the O2 windows and it's pretty good. AFRs are between 14 flat and about 14.8/9-ish. Idle is about 750rpm-ish in drive.

O2 Idle Windows (Mv)
MnR/L - 637.32
Rich - 664.02
Lean- 598.60

However... sometimes... when its coming off the idle (in drive) its a little rough on light throttle (say... less than 10% TPS) for a second until it gets over 1k rpm.

Are these tables too low then- the INT O2 tables? Is there a correlation or need to adjust these tables if I needed to adjust the O2 idle table?

INT - Lean O2
20/ 390.60
30/ 390.60
40/ 390.60
50/ 438.34
60/ 486.08
70/ 490.42
80/ 494.76
90/ 486.08
100/ 477.40

INT - Rich O2
20/ 451.36
30/ 468.72
40/ 481.74
50/ 494.76
60/ 503.44
70/ 499.10
80/ 494.76
90/ 486.08
100/ 477.40

My KPAs during idle move between 60-70kpa in drive... do those values seem low give what the idle windows are?? Or... do I add VE? VE learns are showing 0 changes between 800-1,000rpm. SA is about 20 degrees and stable (+/- 1*).

ULTM8Z

What's your setup? Intake manifold? ECM type? Calibration mask (i.e., $8D)?

CORV3TT3

'82 Vette

• EBL Flash
• 90lb injectors
• VAFPR (20psi)
• Crossfire Dual TBs bored to 49.5mm
• DCS Renegade Intake
• .465" in / .488" ex cam, 224/234, 112 LSA
• Iron '82 Vette heads
• No emissions

I've moved the INT - Lean O2 and the INT - Rich O2 parameters up this morning and completed a VE learn. Lots of 0s, a handful of 1s, 2s, and a few 3s.



It's running very consistent with the WB AFRs now.



New values...



INT - Lean O2
20/529.48
30/564.20
40/581.56
50/581.56
60/564.20
70/546.84
80/494.76
90/486.08
100/477.40




INT - Rich O2
20/451.36
30/655.34
40/672.70
50/672.70
60/655.34
70/637.98
80/581.56
90/564.20
100/551.18




Seems to have helped toggle the AFRs in closed loop to between 14 flat and 14.9 . INT and BLM hover pretty close to 128/128 (+/- 1 or so for either) on a flat-ish roads maintaining speed.



There seems to be less of the light momentary "jiggle" coming off idle at a stop to very light TPS creeping off the stop.

84Elky

Might try increasing TPS AE 10-15% at the lowest few TPS% change values to see what happens. Could be an off-idle tip-in issue.

Dominic Sorresso

OTOH, my WB will indicate a momentary lean when I have closed throttle coming to a stop at low mph. That causes a bit of a idle stumble. DFCO is disabled.
As we play w VE table, we tend to forget that leaning it out will affect the AE pumpshot and don't adjust for this.

CORV3TT3

Thanks Dom- yeah, I've been looking at my AE too as I've been making changes.

Does this look like enough oscillation in closed loop? Have I slowed the gains down too much?


Also... on steady cruise, my BLM and INTs hover around 126 to 131. I usually don't get lower than 118 or higher than 140 going up and down hills and as the conditions change.

I think I can take some fuel out of decel KPAs. I'm running about 12:1 when cAFR should be 14ish. That's a VE table adjustment though.

Dominic Sorresso

As RBob has pointed out, you want the O2 sensor cross counts to take place using the Prop Gain to do it. If the Prop Gain is too low, the INT will wander up and down for the cross counts. If the Prop Gain is too high, the motor will sound like the oscillation of a bad u-joint. At a steady cruise, the motor should have a monotone sound to it. Going up and down hills I try not to vary TPS, so I get a sense of the AE change needs based on MAP deltas.
Now I am thinking that perhaps on a modded motor the threshold for Delta MAP AE, requires a minimum delta of 2.5kPa.

Dominic Sorresso

As RBob has pointed out, you want the O2 sensor cross counts to take place using the Prop Gain to do it. If the Prop Gain is too low, the INT will wander up and down for the cross counts. If the Prop Gain is too high, the motor will sound like the oscillation of a bad u-joint. At a steady cruise, the motor should have a monotone sound to it. Going up and down hills I try not to vary TPS, so I get a sense of the AE change needs based on MAP deltas.
Now I am thinking that perhaps on a modded motor the threshold for Delta MAP AE should be tighter than the required stock minimum delta of 2.5kPa.

CORV3TT3

Thanks!

Yeah, if I let it idle in gear or in park... the INT and BLM really don't budge. They'll sit wherever and stay there.

Definitely have the monotone sound- and no bucking in cruise.

It's really only under load when they'll budge. Mostly when the converter is locked and it hasn't downshifted.