Computers and Control Systems: Adjustments

IDLE SPEED INSPECTION

NOTE:
a. Adjustment of the idle speed is usually unnecessary. Idle speed on fuel injected vehicles is controlled by the MPI Control Unit through the Idle Speed Control Servo.

b. NEW FOR 1991: On Canadian model vehicles, the head lights, tail lights remain lit even after the headlight switch has been turned off. This is caused by the Daytime Running Light circuit, and does not indicate a problem.

Before checking or adjusting the idle speed, be sure:
^ Engine coolant temperature has reached 85-95~C (185-205~F)
^ Lights, engine cooling fan, and electrical accessories are OFF
^ Transmission 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 15~ BTDC @ 700 +/- 100 RPM.

Tachometer Connection:

1. Connect a tachometer to the engine speed detection terminal.

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, 700 +/- 100 RPM.

5. If the idle speed is not within specifications, check the MPI Control System input signals and the Idle Speed Control Servo for proper operation.
Refer to DIAGNOSIS AND TESTING PROCEDURES.