Idle Speed: Adjustments

Adjustment of the idle speed is usually unnecessary.
Idle speed on fuel injected vehicles is controlled by the ECU through the Idle Speed Control Servo. To check the Idle Speed, refer to FUEL INJECTION AND COMPUTERIZED ENGINE CONTROLS.


Basic Idle Speed Adjustment
Before checking or adjusting the Basic Idle Speed:
^ Engine coolant is at operating temperature 85-95°C (185 - 205°F).
^ Lights, all electrical accessories are OFF.
^ Transaxle is in Park or Neutral.
^ Front wheels are in a straight-ahead position, if equipped with power steering.
^ Parking Brake is set.

Tachometer Connection:

1. Connect a tachometer.

Timing Adjustment Connection:

2. Disconnect the waterproof connector from the ignition timing adjustment terminal.
3. Connect the ignition timing adjusting terminal to ground, using a jumper wire with alligator clips.

Self-Diagnosis Terminal:

4. Connect terminal # 10 of the self-diagnosis connector to ground, using a jumper wire with alligator clips.
5. Start the engine and let it run at idle.
6. Check the idle speed to ensure it is at the basic idle speed. Refer to SPECIFICATIONS.
If the idle speed does not meet specifications, check the following before adjusting the basic idle speed.

^ The vehicle has been driven less than 300 miles and engine idle speed is 20-100 RPM low. Then, adjustment is not necessary.
^ The vehicle has been driven more than 300 miles and the engine is stalling or engine idle speed is low. Then, it is possible that there are deposits stuck to the back of the throttle valve and it needs to be cleaned.
^ The engine idle speed is higher than specifications and the speed adjusting screw is fully closed. Then, check for indications that the idle position switch has been changed.

Idle Speed Adjusting Screw:

If there is such an indication, then adjust the idle position switch (speed adjusting screw).
If there is no indication, it is possible that there is leakage resulting from deterioration of the fast idle air valve. The throttle body needs to be replaced.

If the idle speed is within specifications.
7. Turn off the engine.
8. Disconnect the grounding jumper wire from the diagnosis connector.
9. Disconnect the grounding wire form the ignition timing connector and reinstall the waterproof connector.
10. Disconnect the tachometer.
11. Start the engine and let it idle for about 5 minutes. Ensure that the idle speed is at normal Curb Idle. Refer to SPECIFICATIONS.