Ignition Timing: Adjustments

Before making any adjustments of engine settings, activate fault memory to make sure all systems are functioning correctly. Correct any faults before making engine adjustments.
1. Initial setup:
a. Engine at operating temp (80°C/176°F)
b. All electrical consumers turned OFF (radiator fan must not run while making adjustments)
c. Disconnect any fuel pressure gauges.
d. If any fuel injection lines were loosened, or if any fuel injection component was replaced, raise the engine speed above 3000 rpm at least 3 times, then let engine run at idle for two minutes before making adjustments.
e. Exhaust system must be in good condition, with no leaks.
f. Oxygen sensor must be operating properly.
2. With ignition OFF, connect tachometer and timing light.
3. Disconnect crankcase breather hose from the valve cover and vent it to atmosphere.
4. Disconnect crankcase breather from the engine block and vent to atmosphere.
5. With engine at idle, check ignition timing at the window in the bellhousing.
6. Timing should be 6° +/- 1° BTDC
7. If timing is not within specification, remove the anti-tamper cap from the distributor hold down clamp, and loosen the bolt. Turn the distributor until the timing is correct and tighten the hold down bolt to 18 ft/lb.