Computers and Control Systems: Adjustments

IDLE SPEED ADJUST

Air Filter Housing / Intake Air Control Diaphragm:

NOTE: Engine must be at normal operating temperature cooling fans cycling. Remove Vacuum hose from the intake air control diaphragm and plug hose end. This applies to both manual and automatic transmissions.



Manual transmission:

Throttle Stop Screw:

1. Connect tachometer, idle speed should be:

750 +/- 50 rpm.

Check idle speed with the headlights, heater blower, rear window defroster, cooling fan and air conditioner off.

2. If the idle speed is out of specification, adjust the idle rpm using the throttle stop screw.

Adjusting Screw "B" - Manual Transmission:

NOTE: If equipped with air conditioning, check the idle speed with the A/C on. Idle speed should be.

750 +/- 50 rpm.

3. Adjust the A/c idle speed by turning adjusting screw "B".



Automatic Transmission:

Throttle Stop Screw:

1. Lower the idle speed as much as possible by turning the throttle stop screw. All accessories turned off.

Idle Control Screw:

2. Adjust the idle speed by turning the idle control screw to.

600 +/- 50 rpm.

Adjusting Screw "A":

3. With the headlights on, rear defroster on and interior blower fan turned to high speed, adjust the idle speed, by turning adjusting screw "A". Idle speed should be

600 +/- 50 rpm.

Adjusting Screw "B":

4. If equipped with air conditioning, adjust the idle speed by turning idle screw "B", with the a/c turned on. Idle speed should be.

700 +/- 50 rpm

5. With all accessories turned off, remove the inside vacuum hose from the idle boost throttle controller and plug the hose end.

6. Adjust the idle speed by turning the throttle stop screw. Reinstall the vacuum line. idle speed should be.

700 +/- 50 rpm.

NOTE: High altitude vehicles. Idle speed should be.

650 +/- 50 rpm.

7. Raise the engine speed to 2,500 rpm 2 or 3 times in ten seconds, and check the idle speed. Idle speed should be:

700 +/- 50 rpm.

8. Re-check the idle speed with the rear window defroster on, interior blower fan on high, and headlights on. Idle speed should be:

700 +/- 50 rpm.

9. Re-check the idle speed with the automatic transmission in DRIVE RANGE. Idle speed should be:

700 +/- 50 rpm.

10. Re-check the idle speed with the A/C on and the transmission in PARK or NEUTRAL. Idle speed should be.

750 +/- 50 rpm.

11. Re-check the idle speed with the A/c on and the transmission in DRIVE. (Emergency brake applied during this procedure). Idle speed should be:

750 +/- 50 rpm.

NOTE: If in the above tests, the engine does not meet the specified idle speeds, inspect the idle control system.