Ignition Timing

GENERAL INFORMATION

Ignition timing is checked and adjusted using a timing light.

The pulley rim has timing marks spaced at 5° intervals. The first mark is located 20° BTDC, and the last is 5° ATDC. The TDC mark is painted yellow. The arrow indicates the pointer on the front cover.

Inspection and Adjustment

PROCEDURE

1. Warm up the engine, check the idle speed, turn off the ignition.

Carbureted Engines

2. Disconnect the hose from the vacuum regulator (or the pressure sensor hose on engines with catalytic converter) and plug the hose.

3. Connect the timing light in accordance with the manufacturer's instructions.

4. Start the engine and aim the light at the crankshaft pulley. At idle, the illuminated mark must align with the pointer.

5. If adjustment is required, loosen the distributor bolts and turn the distributor body until the mark aligns with the pointer.

6. Tighten the bolts and check the ignition timing again.

7. Check the operation of the centrifugal advance mechanism: as engine speed increases, the scale on the pulley rim should appear to move "forward" relative to the pointer, and when speed drops back to idle, the illuminated mark must again align with the pointer.

8. Connect the hoses and make sure the timing advances and the advance angle is within specification.

9. Otherwise, the vacuum regulator (or pressure sensor) is faulty or there is a leak in the hose.

10. Stop the engine and disconnect the timing light.

Fuel Injection Engines

11. Disconnect the connector from the throttle sensor.

12. Check and adjust the ignition timing (see steps 3–5).

13. Stop the engine and disconnect the timing light.

14. Connect the connector to the throttle position sensor.