Start engine, and warm it 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 diagnostic connector, 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 diagnostic connector. 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 diagnostic connector. Remove test equipment.

Fig 1: Diagnostic Connector Terminal ID

Courtesy of GENERAL MOTORS CORP.

IGNITION TIMING SPECIFICATIONS ⁽¹⁾

Application

Man. Trans.

Auto. Trans.

Metro

⁽²⁾ 5 @ 750-850

⁽²⁾ 5 @ 800-900

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

⁽²⁾	With jumper wire installed between terminals No. 4 ("D") & No. 5 ("E") of diagnostic connector, located on left strut tower.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Ignition Timing