GM Astro/Safari 1985-1996 Repair Guide

Idle Air Control (IAC) Valve

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TESTING



See Figure 1



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Fig. Fig. 1: View of the Idle Air Control (IAC) valve circuit

  1. Disconnect the negative battery cable.
  2.  
  3. Test resistance between terminals A and B, then test between C and D.
  4.  
  5. If the resistance is nor 40-80 ohms, replace the IAC.
  6.  
  7. Connect the neagtive battery cable.
  8.  

REMOVAL & INSTALLATION



See Figures 2 and 3



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Fig. Fig. 2: Exploded view of the Idle Air Control (IAC) valves-Model 220 and 300



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Fig. Fig. 3: Idle Air Control (IAC) valve-Model 700

The following procedure requires the use of the GM Removal tool No. J-33031 or equivalent.

  1. From inside the vehicle, remove the engine cover.
  2.  
  3. Remove the air cleaner. Disconnect the negative battery terminal from the battery.
  4.  
  5. Disconnect the electrical connector from the idle air control valve.
  6.  
  7. Using a 1 1 / 4 in. (approx. 32mm) wrench or the GM Removal tool No. J-33031, remove the idle air control valve (Model 220 and 300). Remove the two retaining screws and valve (Model 700).
  8.  


CAUTION
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 extends to far, damage will occur to the valve when it is installed. Push the valve pintle in slowly with finger pressure until the correct measurement is obtained.

To install:
  1. Use a new gasket and the correct IAC replacement valve.
  2.  
  3. Install the valve and torque the thread mounted valve to 13 ft. lbs. (18 Nm) and the screw mounted valve to 28 inch lbs. (3.3 Nm). Use thread locking compound on the retaining screws before assembly.
  4.  
  5. Connect the valve and negative battery cable.
  6.  
  7. Start the engine and allow it to reach normal operating temperatures. Check for fuel leaks.
  8.  
  9. Turn the ignition ON for 5 seconds and OFF for 10 seconds to allow the IAC valve to reset.
  10.  
  11. The vehicle may have to driven a few miles before the IAC valve will return to normal.
  12.  

The ECM will reset the idle speed when the vehicle is driven at 30 mph (48 kph).

 
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