Computers and Control Systems: Adjustments

IDLE SPEED INSPECTION

Before checking the CURB idle speed, be sure:

^ Engine coolant temperature has reached 85-95~C (185-205~F)
^ Engine cooling fan, lights and electrical accessories are OFF
^ Transaxle is in NEUTRAL or PARK.
^ Steering wheel is at a center position (power steering equipped vehicles)
^ Parking brake is applied.
^ Verify that the ignition timing is set to specifications. Refer to SPECIFICATIONS/ELECTRICAL

Tachometer Connection:

1. Connect a tachometer to the engine speed detection terminal.
NOTE: The tachometer will indicate only of the actual engine speed. Therefore, double the tachometer reading to obtain the actual engine speed.

2. Start and run the engine for more than 5 seconds at 2,000 to 3,000 rpm.

3. Reduce the rpm and let the engine idle for 2 minutes.

4. Read the CURB idle speed. Refer to SPECIFICATIONS/MECHANICAL.

CAUTION: Improper setting of the throttle valve opening will increase exhaust gas temperatures at deceleration, which will greatly reduce the life of the Catalytic Converter. Also, fuel consumption and engine braking will be affected.



IDLE SPEED ADJUSTMENT

1. The tachometer should be connected to the engine speed detection terminal.

Timing Adjustment Connection:

2. Disconnect the waterproof connector from the Ignition Timing Adjustment Terminal, located in the engine compartment.

3. Connect the ignition timing adjustment 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 idle.

6. Check the idle speed to verify the BASIC idle speed.
Refer to SPECIFICATIONS/MECHANICAL. If the idle speed is within specifications, proceed to step # 7.

NOTE: If the idle speed does not meet specifications, check the following before adjusting the BASIC idle speed.

a. If the engine is stalling or the idle speed is below specifications, check for deposits stuck to the back of the throttle valve. If so, the throttle valve needs to be cleaned.

Idle Position Switch (Fixed Speed Adjusting Screw):

b. The engine idle speed is higher than specifications and the speed adjusting screw are fully closed. Then, check for indications that the Idle Position Switch has been changed.

c. 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.

Idle Speed Adjusting Screw:

If none of the above conditions apply, then turn the speed adjusting screw until the engine is at the BASIC Idle Speed.

7. Turn OFF the engine.

8. Disconnect the grounding jumper wire from the diagnosis connector.

9. Disconnect the grounding wire from the Ignition Timing Adjustment Terminal and reinstall the waterproof connector.

10. Start the engine and let it idle for about 5 minutes. Verify the idle is smooth and has returned to CURB Idle Speed.

11. Disconnect and remove the tachometer.