Ignition Timing: Adjustments

Vacuum Advance Hoses:

1. Warm up the engine to normal operating temperature, and check the condition of the engine (spark plugs, leaks in hoses, etc.).
2. Turn all electrical loads OFF.
3. Disconnect the vacuum hoses from the vacuum control unit and plug them.

Test Connector:

4. Connect a tachometer to the engine and connect a jumper wire between the test connector and ground. Check the idle speed. The idle speed should be 850±50 rpm with the transmission in neutral (MTX) or park (ATX).
5. If the idle speed is not to specifications, proceed as follows:
a. Remove the blind cap from the air adjusting screw and adjust it.
b. After adjusting the idle speed, install the blind cap and disconnect the jumper wire from the test connector.
6. If not already done, disconnect the jumper wire from the test connector.

Timing Marks:

7. Connect a timing light to the engine and check the ignition timing. Initial timing should be 2±1° BTDC.

Adjusting Ignition Timing:

8. If the ignition timing is not within specifications, loosen the distributor body installation bolt and adjust the ignition timing by turning the distributor.
9. Reconnect the vacuum hoses to the vacuum control unit and recheck the ignition timing. The ignition timing should be approx. 7° BTDC.
10. If the timing is not approx. 7° BTDC, see IGNITION SYSTEMS section.
11. Connect a jumper wire between the test connector (Green 1-pin) and ground.
12. Ensure that the transmission is in neutral (MTX) or park (ATX), then check the idle speed. The idle speed should be 850±50 rpm.

Adjusting Idle Screw:

12. If the idle speed is not within specification, remove the blind cap from the air adjusting screw and adjust it.
13. After adjusting the idle speed, install the blind cap and disconnect the jumper wire from the test connector.