Ignition Timing Adjustment

Timing Mark:

An averaging method is used to check the ignition timing for this engine. The averaging method is a process in which the timing of each cylinder can be brought into closer agreement with the base timing specification.

Set timing under the following conditions:

1. Verify that NO "SERVICE ENGINE SOON" light exists.
2. The vehicle should be running at normal operating temperature.
3. All engine loads should be OFF.
4. The transmission should be in Park or Neutral.
5. The engine should be running at idle speed. See SPECIFICATIONS/MECHANICAL.

The Adjustment Procedure is as follows:

1. Ground the ALDL connector located behind the right hand kick pad. The "SERVICE ENGINE SOON" light will flash.
2. Connect a timing light inductive pick-up to the Number 1 spark plug wire.
3. Record the position of the timing mark.
4. Connect the timing light to the number 4 spark plug wire and record the timing mark.
5. Add the total of the two readings, and divide by 2. This is the average timing.
6. If an adjustment is necessary, subtract the average timing from the specification. This is the amount the timing needed to be changed. Reconnect the timing light to the number 1 wire and adjust timing. (See SPECIFICATIONS/ELECTRICAL AND ELECTRONIC for timing specifications.)
NOTE: Loosen the hold down bolt, and rotate the distributor to adjust timing. Tighten the hold down and recheck the timing.
7. Remove the ground from the diagnostic connector and verify NO "SERVICE ENGINE SOON" light exists.