Ignition Timing Adjustment

Fig. 67 Disconnecting Vacuum Advance Hose:

1. Confirm initial inspection conditions:

a. Engine coolant temperature is 176 - 203°F.
b. Lights, cooling fan and all accessories are OFF.
c. Transmission is in neutral or park.
d. Steering wheel is in straight-ahead position, (on vehicles with power steering).

2. Connect a strobe timing light to the engine.
3. Start the engine and check that idle speed is correct. Adjust idle speed, if necessary. (Refer to procedure)

Curb Idle Speed: 750 ± 100 RPM

4. Disconnect the vacuum hose from the distributor sub-diaphragm, (White stripe), and plug the hose end. Fig. 67

Fig. 29 Checking Ignition Timing:

5. Using the timing light, check the ignition timing at idle speed. Fig. 29

Base Ignition Timing: 8 ± 2° BTDC

6. If not as specified, loosen distributor hold down nut and rotate the distributor housing until the timing marks align.
7. Tighten hold down nut and reconnect the vacuum hose.
8. Check the idle advance ignition timing.

Idle Advance Timing: 8 - 13° BTDC

9. Stop engine and remove timing light.