High IAC Help

[HotAirGN]

Finally have a scanmaster and decided to get some baseline numbers last night.
AF 5
L8 38-41
bAT 13.2-13.5
Int 128
bL 128
Mph 0
CLt 167
AtS 98
r 800
tPS .38
IAC 64

By adjusting last night I could only get it to 50 as the lowest. Try again today and adjust by engine on/off a couple times and no matter how much I adjust in either direction the IAC won't get out of the 70's.

When I get home from work I will pull the sensor and clean it but when can you tell if it is bad and then just replace it?

 

[dennisL]

The ecm uses the IAC to maintain or stay close to the programmed target rpm. The IAC count starts at a high number then goes down as the engines warms up. If the idle rpms are not erratic and the hot engine idle rpm is close to the chip's target speed then the IAC is working.

Be careful cleaning the IAC so that just the part that moves in/out is exposed to a solvent. Do not submerge the entire IAC in solvent.

After you replace it, you should perform the reset procedure.
1) Jumper ALDL connector pins A and B. (top right two pins)
2) Turn the ignition on but do not start the engine. The ECM sets the IAC count to zero. Wait 30 seconds so the IAC has more than enough time to seat the pintle.
3) Then with ignition still on, disconnect the IAC electrical connector. (Be careful, not much room.)
4) Turn the ignition off, remove the ALDL jumper, and reconnect the IAC electrical connector.
5) This establishes the seated or zero reference point. The next time the ignition is turned on, the IAC will go to a count of 150, then to the start count (based on coolant temp.), then count down (extend) as the engine warms.

Make sure the engine is fully warmed (HOT) before making the Min Air screw adjustment. Finally, readjust your TPS to 0.44V, shut off engine, restart, check IAC count and TPS voltage.

Dennis

 

[HotAirGN]

Finally figured it out. I thought The IAC could either be set to 0 or 150 at one time turning from one end to the other. Once I was in the 50's I had a real high idle. Turn the car off and adjust the TPS there then started it back up. Was able to further turn without the RPM shooting up and finally was able to get my IAC to 24.

So for those who search on this later. Get the reading as low as you can, reset TPS, lower IAC the rest of the way, reset TPS again and you should be there.