Ignition System

Check the spark plugs for proper heat range and reach. See IGNITION SYSTEM SPECIFICATIONS in appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article. Check for proper ignition voltage output using the following steps:

1. Attach Spark Tester (J 26792) to engine ground.
2. Connect the spark plug end of the spark plug wire to the spark tester. Connect the other end of the spark plug wire to the coil being tested.
3. Connect the spark plug end of the companion spark plug wire to ground. The companion spark plug wire is the wire attached to the corresponding coil tower.
4. Crank the engine while observing the spark tester. A spark should be observed.
5. Repeat steps  1 - 4 for each coil.

If spark is not present at the coils, check for the following conditions:

1. Coils  - Cracks, carbon tracking/arcing, or a resistance value outside 5-8 k/ohms.
2. Spark Plug Wires  - Signs of arcing, cross firing, cracks, carbon tracking, plug boot damage, pinched, improper routing, or a resistance value outside 3000 ohms per foot (9868 ohms per meter). Spraying the secondary ignition wires with a light mist of water may help locate an intermittent condition. Ignition voltage arcs to ground when a secondary component is faulty.
3. Defective Ignition Module  - See ELECTRONIC IGNITION SYSTEM DIAGNOSIS under IGNITION SYSTEMS in SYSTEM & COMPONENT TESTING - 3.1L CENTURY, GRAND PRIX & MALIBU article.
4. Ignition System Wiring  - Loose ignition module feed or ground connection, or damaged system wiring.

Remove spark plugs and check for the following conditions:

• Fouled plugs.
• Cracks.
• Wear.
• Improper gap.
• Burned or damaged electrodes.
• Improper heat range or reach.

If spark plugs are gas or oil fouled, the cause of the fouling must be determined before replacing the spark plugs.