I am trying to solve an idle surge/misfire issue and need some guidance please.
I tried changing the o2 constants to:
Fast o2 R/L Threshold at Idle .502
Fast o2 R/L Hysteresis at Idle .053
Upper Zero Error Ref Slow o2 R/L at Idle .502
Lower Zero Error Ref Slow o2 R/L at Idle .466
Still surges!
I am tuning $8D "727" in a 383 First TPI, cast pre smog heads 9:1 CR, Bosch NB o2 in 2.5 in corvette exhaust manifolds, mild cam LPE74216 (43 deg overlap @ .050).
Datalogs look ok no obvious probs, no codes, IAC 0 steps at 180 deg, new flow matched 24lb bosch injectors, plug wires ohm checked within specs plugs look good.
The only other symptom is what seems like a slight misfire. Plugs gaped at .035 and BLMs look good. Could this be something else? SA? ign module?
Thanks in advance!

 

If you are running 0 steps the IAC cannot help to control idle. Might want to try 10-15 steps and see if it helps.
The problem could be in spark cells being too different in the idle or main table,
or your RPM error tables have too much effect. Reducing the lower error cells (below 100 error) will make the SA more stable at idle.
These are a $81F0 and $81EB

 

Thanks for the info! I am using tuner cat and I would like to know how are these idle error tables named? Are the o2 constants ok? I am not using a cat and will upgrade to a WBO2 when I start to do the part throttle and WOT tuning. Oh, one more thing. I intended to communicate that the IAC steps are set to 40 and increase normally when cold starting then come down to 0 when at 180 deg.

 

That fixed mine