Chrysler Full-Size Trucks 1967-1988 Repair Guide

Automatic Idle Speed (AIS) Motor

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See Figure 1

The Automatic Idle Speed (AIS) motor assembly is operated by the SMEC. Data from the throttle position sensor, speed sensor, coolant temperature sensor, and various switch operations, (electric backlite, air conditioning, safety/neutral and brake) are used by the module to adjust the engine to an optimum idle during all conditions. The AIS adjusts the air portion of the air/fuel mixture through an air bypass on the back of the throttle body. Basic (no load) idle is determined by the minimum air flow through the throttle body. The AIS opens or closes off the air bypass as an increase or decrease is needed due to engine loads or ambient conditions. Deceleration die out is also prevented by increasing engine idle when the throttle is closed quickly after a driving (speed) condition.



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Fig. Fig. 1: Adjust the idle speed control actuator

REMOVAL & INSTALLATION



  1. Remove the air cleaner.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Unplug the four pin connector on the AIS.
  6.  
  7. Remove the temperature sensor from the throttle body housing.
  8.  
  9. Remove the Torx® head screws (usually 2).
  10.  
  11. Remove the AIS from the throttle body housing, making sure that the O-ring is with the AIS.
  12.  

To install:
  1. Install new a O-ring on the AIS.
  2.  
  3. Install the AIS into the housing making sure the O-ring is still in place.
  4.  
  5. Install the Torx® head screws.
  6.  
  7. Engage the four pin connector to the AIS.
  8.  
  9. Install the temperature sending unit into the throttle body housing.
  10.  
  11. Connect the negative battery cable.
  12.  

 
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