GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Idle Air Control (IAC) Valve



See Figure 1

  1. Disconnect the negative battery cable.
  3. Disengage the electrical connector from the idle air control valve.
  5. Loosen and remove the IAC valve retaining bolts, then remove the valve from the engine.

To install:

Before installing a new idle air control valve, measure the distance that the valve extends (from the motor housing to the end of the cone); the distance should be no greater than 11/8in. (28mm). If it is extended too far, damage may occur to the valve when it is installed.

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Fig. Fig. 1: Measuring the IAC valve pintle

  1. Measure the valve pintle extension. To retract the pintle on a NEW valve, use firm thumb pressure and, if necessary, rock the pintle with a slight side-to-side motion. BUT, if reinstalling a used valve on which the pintle is extended further than specification, an IAC tester MUST be used to electrically retract the pintle.

Do not attempt to physically retract a pintle on an IAC valve that has been in service, the force may damage the pintle threads. The force required to retract the pintle is only safe on NEW IAC valves.

  1. Lightly coat the IAC valve O-ring with clean engine oil.
  3. Inspect the retaining screw threads for threadlocking material. If there is no longer sufficient material on the threads, clean the threads and apply Loctite®262 or equivalent. DO NOT use a stronger compound or future bolt removal may be difficult.
  5. Install the IAC valve and tighten the retaining bolts to 27 inch lbs. (3.0 Nm).
  7. Engage the valve electrical connector.
  9. Connect the negative battery cable.
  11. Reset the IAC valve pintle: turn the ignition ON (engine NOT running) for 5 seconds, then turn the ignition OFF for 10 seconds. Start the engine and check for proper idle operation.