GM Firebird 1982-1992 Repair Guide

Idle Air Control (IAC) Valve



See Figure 1

  1. Unplug the electrical connector from idle air control valve.
  3. Remove the idle air control valve.

To install:
  1. Before installing the idle air control valve, measure the distance that the valve is extended. Measurement should be made from the motor housing to the end of the cone. It should not exceed 28.5mm (1 1 / 8 in.), or damage to the valve may occur when installed.
  3. Identify the replacement IAC valve as being either Type 1 (with collar at electric terminal end) or Type 2 (without collar). If measuring distance is greater than specified above, proceed as follows:

    Type 1: Use finger pressure to slowly retract the pintle.
    Type 2: Compress retaining spring from valve while turning valve in with a clockwise motion. Return spring to original position with straight portion of spring end aligned with flat surface of valve.


On IAC valves that have already been in service, do not push or pull on the valve pintle. The force required to move the pintle may damage the threads on the worm drive.

  1. Use a new gasket or O-ring and install the IAC valve into the throttle body.
  3. Allow the ECM to reset the idle air control valve using the procedure described earlier in this section.

Click image to see an enlarged view

Fig. Fig. 1: Idle air control valve installation