Ignition Timing

IGNITION TIMING SPECIFICATIONS (Degrees BTDC @ RPM) ⁽¹⁾

Application

Man. Trans.

Auto. Trans.

Metro

⁽²⁾ 5 @ ⁽³⁾

⁽¹⁾	If specification differs from emission label, use specification listed on emission label.

⁽²⁾	With jumper wire installed between terminals "D" (Black wire) and "E" (Purple/Green wire) of duty check data link connector, located on left strut tower.

⁽³⁾	Specified idle. See emission label located on vehicle.

Warm engine to normal operating temperature. Turn engine off but keep ignition on for 5 seconds. Restart engine, and raise engine speed to 2000 RPM for 5 minutes. Return to idle. Ensure all accessories are off and idle speed is within specification. Adjust idle speed first if it is not within specification. See IDLE SPEED under IDLE SPEED & MIXTURE.
Connect timing light to No. 1 spark plug wire. Remove cap from duty check Data Link Connector (DLC), located in rear corner of engine compartment near left strut tower. Connect a jumper wire between terminals "D" (Black wire) and "E" (Purple/Green wire) of duty check DLC. See Fig 1 .
Check timing mark alignment on crankshaft pulley with timing marks on timing belt cover. Ignition timing must be within specification. See IGNITION TIMING SPECIFICATIONS .
If ignition timing is not as specified, loosen distributor hold-down flange bolts, and rotate distributor to obtain correct ignition timing. Tighten distributor hold-down flange bolts to 11 ft. lbs. (15 N.m). Recheck ignition timing.
Turn engine off. Remove jumper wire, and install cap on duty check DLC. Remove test equipment.

Fig 1: Identifying Duty Check DLC Terminals

Courtesy of GENERAL MOTORS CORP.