Inspect the terminal post for damage
Inspect for a bent or broken terminal post
Inspect the insulator for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator between the terminal post and ground. Inspect for the following conditions:
Inspect the spark plug boot for damage
- Inspect the insulator for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes
- Inspect for evidence of improper arcing
- Measure the gap between the center electrode and the side electrode terminals. An excessively wide electrode gap can prevent correct spark plug operation.
- Inspect for the correct spark plug torque. Insufficient torque can prevent correct spark plug operation. An over-torqued spark plug causes the insulator to crack.
- Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode
- Inspect for a broken or worn side electrode
Inspect for a broken, worn, or loose center electrode by shaking the spark plug.
A rattling sound indicates internal damage
- Inspect for bridged electrodes. Deposits on the electrodes reduce or eliminates the gap.
- Inspect for worn or missing platinum pads on the electrodes if equipped
- Inspect for excess fouling
- Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation
- Normal operation--Brown to grayish-tan with small amounts of white powdery deposits are normal combustion by-products from fuels with additives.
Carbon fouled--Dry, fluffy, black carbon, or soot caused by the following conditions:
Rich fuel mixtures
- Deposit fouling: Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.
Removal & Installation
3.4L & 3.5L Engines
- Turn the ignition OFF
- For 3.5L engine, remove the intake manifold cover.
- Remove the spark plug wire(s) (2, 4, and 6) from the left side spark plug(s).
- Remove the air cleaner outlet duct.
- Set the park brake.
- Shift the transaxle into neutral (N).
- Remove the left and right engine mount struts.
- Install the J 41131 rotation tool.
- Pull on the engine in order to rotate the engine forward.
- Tighten the J 41131 tool.
- Remove the spark plug wire(s) (1, 3, and/or 5) from the right side spark plug(s).
- Remove the spark plug(s) from the cylinder head.
Gap the spark plugs to 0.60 inches (1.52mm).
NOTEBe sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.
NOTEUse the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
- Install the spark plug(s).
- If the spark plugs are installed into a new cylinder head, tighten the spark plugs to 15 lb-ft (20 Nm). If the spark plugs are installed into an existing cylinder head, tighten the spark plugs to 11 lb-ft (15 Nm).
- Install the spark plug wire(s) (1, 3, and 5) to the right side spark plug(s).
- Carefully release the tension on the J 41131 tool.
- Remove the J 41131 tool.
- Install the left and right engine mount struts.
- Install the spark plug wire(s) (2, 4, and/or 6) from the left side spark plug(s).
- For 3.5L engine, install the intake manifold cover.
- Turn the ignition OFF .
Remove the ignition coil.
CAUTIONWear safety glasses when using compressed air in order to prevent eye injury.
NOTEClean the spark plug recess area before removing the spark plug. Failure to do so could result in engine damage because of dirt or foreign material entering the cylinder head, or by the contamination of the cylinder head threads. The contaminated threads may prevent the proper seating of the new plug. Use a thread chaser to clean the threads of any contamination.
Use compressed air in order to remove debris from the spark plug cavity.
NOTEAllow the engine to cool before removing the spark plugs. Attempting to remove the spark plugs from a hot engine may cause the plug threads to seize, causing damage to cylinder head threads.
- Remove the spark plug.
Gap the spark plugs to 0.044 inches (1.10 mm).
NOTEBe sure that the spark plug threads smoothly into the cylinder head and the spark plug is fully seated. Use a thread chaser, if necessary, to clean threads in the cylinder head. Cross-threading or failing to fully seat the spark plug can cause overheating of the plug, exhaust blow-by, or thread damage.
- Install the spark plugs.
- Tighten the spark plugs to 15 ft. lbs. (20 Nm).
- Install the ignition coil.