Ignition Timing: Adjustments

NOTE: DO NOT USE A SCAN TOOL FOR THIS PROCEDURE.

Preconditioning

- Engine coolant temperature greater than 176-205° F (80-95° C).
- Lights, electric cooling fan, and all accessories off.
- Transmission in neutral or park.

Check Idle Speed

Tachometer Hookup:

1. Install a paper clip into the tachometer check connector (blue).
2. Connect a tachometer to the clip.

Ignition Timing Adjustment Terminal:

3. Start and run the engine at idle. Verify idle speed is within specification, (multiply the tachometer reading by 3 for idle rpm).

Curb Idle Speed

700±100 rpm

Check and Adjust Basic Timing

1. Turn engine OFF, remove the waterproof cover and ground the ignition timing adjustment terminal (brown), with a jumper lead.
2. Connect a timing light to the #1 spark plug wire, START the engine and allow it to run at curb idle speed.
3. Check the timing.

Basic Ignition Timing

5° ±2° BTDC.

Crankshaft Position Sensor:

4. If timing is not within specification, check the operation of the crankshaft position sensor and ignition control components. SEE COMPUTER S AND CONTROL SYSTEMS/ DIAGNOSIS AND TESTING.

Check Actual Timing

1. Stop the engine.
2. Disconnect the ignition timing jumper wire and RE-START the engine.
3. Check the timing.


Actual Ignition Timing

15° BTDC.


NOTE: Actual ignition timing may vary slightly (±7°), under the direction of the ECM. If necessary re-check Basic Ignition Timing. If it is still correct no further action is required. At altitudes more than 700 m (2,300 ft) above sea level, the Engine Controller may advance the actual ignition timing (5°).