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.

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.


4. If necessary loosen the distributor mounting nut and adjust timing by rotating the distributor, tighten hold down nut to 10 ft-lbs (14 NM).


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 further advance the actual ignition timing.