Hello All
I am trying to adjust the Minimum Air Positiion, The IAC is fully extended and unpluged. Pin A and B is jumpered on the ALDL. I have the EST disconnected. When I start the car, I can not get the car to idle at 450, I back out the screw as much as I can, however the butterfly valve will not close anymore. So there is a gap between the minimum air screw and the butterflay/adjustment plate. (I hope that makes sence). All comments and suggestions will be greatly appreciated. I have a 1989, Firebird, TBI, 305, Vin Code E.

Thanks
Brad
San Diego

 

What CAN you get it down to?

I think anything under 700 is fine especially if its cold outside.

 

BG,

The specification is for 400-450 RPM in DRIVE with an automatic. This adjustment, like almost all others, should be done only after the engine has been fully warmed to operating temperature. Intake air temperature is irrelevant, but coolant temperature is very important. You must be at least above 176°F coolant temperature to adjust this properly.

If the RPM cannot be adjusted down far enough, remove the IAC motor and clean the IAC pintle and the valve seat in the air passages of the throttle body. Make sure the throttle plates are correctly aligned, not binding, and fully closed. Eliminate any suspect vacuum leaks. Make sure the TPS voltage is at or below 0.54 VDC for this adjustment, and make sure the IAC motor electrical plug is completely disconnected.

If you are setting minimum air on a car with a manual transmission, the target is 450-550 RPM in neutral, but the procedure is the same.