I recently changed my IAC motor and since I haven't been able to get a consistant idle. So I tried to adjust the minimum air by the method in the tech article. I turn my key on and wait 30 seconds then I jump pins A and B then I removed the connection to the IAC motor then removed the jumper wire between the two pins. Then I start the car and it starts and dies instantly. I even turned the screw for the throttle plates way out to see if that would help but the same thing happened. If I unplug the IAC motor with the car running there doesn't seem to be a difference. My throttle body and all the passages are clean. I don't know, maybe my new IAC motor is bad.

 

I believe you need to shunt pins A&B, and then wait 30 seconds, during which time you will hear the IAC stepping in. After 30 seconds it should be fully seated, at which time you unplug it. Then you remove the A&B shunt and start the motor and set the idle.

Mark.

 

89Formula350tpi,
I just read something in a library book about the IAC operation. I'll post it here, pay attention to the last 2 sentences. Maybe this is what you need to do.

"The IAC or idle air control valve mounted in the throttlebody is designed to control engine idle speed and prevent stalling due to changes in engine load at startup. It also provides cold start fast idle during the warmup period. A conical valve called a pintel moves in annd out against its seat to control the amount of air being bled past the throttle blades. If RPM is too low, more air is bypassed; if RPM is too high, less air is bypassed. The ECM moves the valve in small steps called counts. Engine idle speed is a function of total airflow calculations based on the IAC valve position, throttle valve opening, PCV flow, and calibrated flow loss to vacuum accessories. If the idle air adjustment is off it can be reset by stopping the engine. Depress the accelerator pedal slightly and start the engine for 5 seconds, then turn the ignition off for 10 seconds."