IAC 0 counts at Warm Idle? And O2 sensor question.. TPI 350

mike_350_TPI · Post by **mike_350_TPI** » Mon Oct 13, 2008 6:31 am

Hi,

I have a 1992 Camaro (350 TPI, speed density) and trying to fix a rough, slightly surging idle. I've set the minimum air and TPS. I've also checked for vacuum leaks. However, after warming up the IAC motor keeps going down to 0 counts. It is my understanding that it should not go to 0, but stay around 10-20 counts at warm idle. Upon driving the IAC does open and close with the engine load, so I am thinking it is working right????

Currently I am just using tunerpro to monitor and troubleshoot and am not into tuning or burning chips.

Can anybody familiar with the speed density TPI camaro's please give me some advice on the IAC 0 count issue.

FYI - During my last session at warm idle, the BLM was 136-144 and MAP was ~36pKa. IAC was at 0 counts. Another thing I noticed was the O2 sensor reading was pretty steady while in open loop, but once closed, the value was rather eradic fluctuating from ~250-800mV. Is this normal?

Thanks,

Mike

Sammy · Post by **Sammy** » Mon Oct 13, 2008 6:05 pm

i've always worked off the setting of 5-20 steps at idle for the IAC .. in my opinion you want to have a few steps so the iac can control the idle so you may want to close the butterfly just a bit to get the iac steps up .... aslong as the TPS reading is still within range it shouldn't effect it.

i think from what i read that aslong as the TPS voltage is below .7v it assumes its 0% throttle .... it might be .47v i can't remember.