95 LT-1 Idle Cell Comparison - Humidity?

[spfautsch]

Mitch am I mis-remembering, or did I read somewhere that you'd also drilled out your port orifices (the holes pointing at the injector tips)?

It sounds like there might be some misunderstanding and confusion on the subject - the how-to I've seen about setting a base bypass hole size and adjusting the throttle blades fails to mention that it should be done at maximum air density for the climate you drive in. For example if you're in a cold weather season and consequently high air density, you want lower IAC counts - say in the 20s at hot idle. This is the point where the engine needs the least amount of idle airflow.

I'm at the other extreme of the spectrum. In minimum air density situations you want enough bypass air to reach your idle target speed during a cold start without maxing out the IAC motor (160). This is when the engine needs the maximum amount of idle airflow.

Thereseems to be startup values in tables but it usualy starts as 160 ish.

If you're logging 160 IAC counts during cold starts it's an indication that the engine speed is below your idle target and the ecu has opened the IAC as far as it can trying to correct the situation with more airflow.

All this of course assumes your IAC position has been learned by the ecu. There's no feedback mechanism for the pintle position. The ecu has a relearn procedure it uses to extrapolate when the pintle is fully closed and then stores that position (not sure where or how) and tracks it whenever it commands a change in IAC position. But if you replace your IAC motor or the position is otherwise lost by the ecu, the counts aren't going to be very meaningful until the relearn routine runs. I other words, if your ecu thinks the IAC motor is at 50 and it's actually fully open, there's no way for it to know and it will continue to command it open in steps until the ecu's tracking variable is also at 160.