Pontiac Fiero 1984-1988 Repair Guide

Idle Air Control (IAC) Valve

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The Idle Air Control (IAC) valve is mounted on the throttle body assembly and provides a constant idle speed regardless of engine loads or driving conditions. The IAC valve controls the amount of air that enters the engine by the way of a ECM signal.

REMOVAL & INSTALLATION



2.5L Engine
1984-86 MODELS
  1. Disconnect the negative (-) battery cable.
  2.  
  3. Remove the air cleaner assembly.
  4.  
  5. Remove the Idle Air Control Valve (IAC) electrical connector.
  6.  
  7. Using a 1 1 / 4 in. wrench, remove the IAC valve from the throttle body.
  8.  

Before installing a new IAC valve, measure the distance that the conical valve (pintle) extends. The measurement should be made from the valve housing to the end of the pintle cone. The distance should be no greater than 1 1 / 8 inch (28mm). If the pintle cone is extended too far, damage to the IAC valve may occur when installed.

1987-88 MODELS

The IAC valve is flange mounted, with a dual taper and 10mm diameter pintle. If replacement is necessary, only an IAC valve with the correct part No. having the correct pintle shape and size may be used.

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Remove the IAC valve electrical connector.
  4.  
  5. Remove the two attaching screws and the IAC valve.
  6.  


WARNING
Under no circumstances should the valve pintle be tampered with by hand, screwed or pushed in, or pulled out because damage may result.

To install:

  1. Lubricate the new O-ring seal with automatic transmission fluid and install on the IAC valve.
  2.  
  3. Install the IAC valve to the throttle body.
  4.  
  5. Coat the two IAC valve attaching screws with thread locking compound and torque to 28 inch lb. (3.2 Nm).
  6.  
  7. Install the IAC electrical connector. Reconnect the negative (-) battery cable.
  8.  
  9. Start the engine and allow to reach operating temperature. Check the idle speed with a tachometer.
  10.  

2.8L Engine


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Fig. Fig. 1 The Idle Air Control (IAC) valve is threaded into the throttle body

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Remove the air duct assembly.
  4. &nbs