NOTE: Base (initial) ignition timing is NOT adjustable on this engine. Do not attempt to adjust ignition timing by rotating the distributor.
All ignition timing functions are controlled by the Powertrain Control Module (PCM). The DRB scan tool may be used to verify base timing and electronic timing advance. Refer to the appropriate Powertrain Diagnostics Procedure for operation of the DRB Scan Tool.
Fuel synchronization can be verified and set by rotating the distributor. Refer to the Distributor Removal/Installation, Checking Distributor Position.
Thanks Roy, I had to pull the distributor as one of the cap screws had broken off. I got that fixed and put distributor back in, started engine and rotated the distributor until it ran somewhat smooth. I can limp up to my mechanic who has the proper diagnostic tools but is that safe to do? I ahve a timing light, should I try to find the base timing with it? Thanks, Ernie
No. Base ignition timing is not adjustable on any engine. Distributors do not have built in centrifugal or vacuum assisted advance. Base ignition timing and timing advance are controlled by the Powertrain Control Module (PCM) Because a conventional timing light can not be used to adjust distributor. To verify correct distributor rotational position, the DRB scan tool must be used. Connect DRB scan tool to data link connector. The data link connector is located in passenger compartment, below and to left of steering column. Gain access to SET SYNC screen on DRB. Follow directions on DRB screen and start engine. Bring to operating temperature (engine must be in "closed loop" mode). With engine running at idle speed, the words IN RANGE should appear on screen along with 0°. This indicates correct distributor position. If a plus (+) or a minus (-) is displayed next to degree number, and/or the degree displayed is not zero, loosen but do not remove distributor holddown clamp bolt. Rotate distributor until IN RANGE appears on screen. Continue to rotate distributor until achieving as close to 0° as possible. After adjustment, tighten clamp bolt to 22.5 N·m (200 in. lbs.) torque. The degree scale on SET SYNC screen of DRB is referring to fuel synchronization only. It is not referring to ignition timing. Because of this, do not attempt to adjust ignition timing using this method. Rotating distributor will have no effect on ignition timing. All ignition timing values are controlled by powertrain control module (PCM)