Inspect timing mark and timing mark notch. Clean marks if necessary. See Figure . Start and warm engine to normal operating temperature. Ensure idle speed is correct. See IDLE SPEED SPECIFICATIONS table. Turn off engine and all accessories. Attach timing light to No. 1 spark plug wire.
Unplug cap from diagnostic connector, located near ignition coil. Connect a jumper wire between terminals "C" and "D". See Fig 1 . Start engine and aim timing light at crankshaft pulley and note ignition timing.
If timing is not within specification shown on underhood emissions label or in IGNITION TIMING SPECIFICATIONS table, loosen distributor hold-down flange bolts and rotate distributor to obtain correct ignition timing. Tighten distributor hold-down flange bolts to 10 ft. lbs. (13 N.m) and recheck timing.
Remove jumper wire between terminals "C" and "D" of diagnostic connector and install cap. Check ignition advanced timing with specification on underhood emissions label. Turn ignition off, remove timing light.

Fig 1: Identifying Diagnostic Connector Terminals (Metro With Electronic Spark Control)

Courtesy of GENERAL MOTORS CORP.

IGNITION TIMING SPECIFICATIONS (Degrees BTDC @ RPM)

Application

Man. Trans.

⁽¹⁾ Auto. Trans.

Metro LSi w/o ESC

w/o Vacuum

6-7 @ 750

6-7 @ 850

w/Vacuum

12-13 @ 750

12-13 @ 850

Metro w/ESC

⁽²⁾ 5 @ 750

⁽²⁾ 5 @ 850

⁽¹⁾	With automatic transmission in Park or Neutral.

⁽²⁾	With jumper wire installed in diagnostic connector, located next to ignition coil. See Fig. .

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

Metro w/Electronic Spark Control (ESC)