While periodic adjustment is not necessary, ignition timing may need to be adjusted when the distributor has been removed for repairs, such as cylinder head removal, or when all other causes of an engine performance problem have been eliminated and the symptoms suggest an ignition timing problem.
When checking ignition timing, observe the following conditions:
- Apply the parking brake and be sure that the vehicle is in park.
- Start and run the engine at about 2000 rpm for about two minutes.
- Turn the engine OFF and disconnect the throttle position sensor harness connector, located at the throttle body between the intake manifold and air cleaner-to-intake manifold hose.
- Connect a tachometer, following the manufacturer-s instructions.
- Connect the timing light, following the manufacturer-s instructions. The pickup should be connected to the #1 cylinder spark plug wire.
- Start the engine and rev it two or three times to 2,000-3,000 rpm. Allow the engine to return to idle for a minute.
Check the engine idle speed. The idle speed should be 650-750 rpm. If not, determine the cause and make the necessary repairs or adjustments.
CAUTIONKeep away from moving engine parts such as the cooling fan and drive belts. Do not wear loose clothing or jewelry while under the hood of the car with the engine running.
- Aim the timing light at the timing pointer, which is located at the center of the timing cover above the crankshaft pulley. The 15°BTDC notch on the crankshaft pulley should align with the timing pointer.
- If timing is incorrect, loosen the distributor hold-down bolt and rotate the distributor to align the specified notch with the timing pointer. Rotate counterclockwise to advance timing or clockwise to retard.
- Tighten the distributor hold-down bolt to 10-12 ft. lbs. (14-17 Nm)and recheck the timing to ensure that the distributor did not move while tightening.
- Turn the engine OFF . Disconnect the timing light and tachometer.
- Reconnect the throttle position sensor harness connector.