GM Metro/Sprint 1985-1993 Repair Guide

Idle-Up System

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ADJUSTMENT



See Figure 1



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Fig. Fig. 1: Idle-up system adjusting screw - carburetor

1985-88 Carbureted Vehicles

The cooling fan runs and stops automatically according to the coolant temperature. For this reason, make sure that the cooling fan is not running before performing idle-up system check and adjustment.

MANUAL TRANSAXLE
  1. Start the engine and allow it to reach operating temperature.
  2.  
  3. Run the engine at idle and check to see that the idle-up screw moves when the lights are turned ON .
  4.  
  5. Ensure that the heater fan, rear defogger, engine cooling fan and air conditioner are all OFF .
  6.  
  7. Turn the lights ON and check that the idle speed is within specification or slightly higher. If not, adjust by turning the adjusting screw on the back of the idle-up solenoid.
  8.  
  9. After adjustment, repeat Step 2 and check for idle-up screw movement.
  10.  

AUTOMATIC TRANSAXLE
  1. Start the engine and allow it to reach operating temperature.
  2.  
  3. Run the engine at idle, apply the parking brake and block drive wheels.
  4.  
  5. Ensure that the heater fan, rear defogger, engine cooling fan and air conditioner are all OFF .
  6.  
  7. With the brake pedal depressed, shift drive selector lever into D and check to see that the idle-up screw moves down.
  8.  
  9. Check that the idle speed is within specification or slightly higher. If not, adjust by turning the adjusting screw on the back of the idle-up solenoid.
  10.  
  11. After adjustment, repeat Step 4 and check for idle-up screw movement.
  12.  

 
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