Spark Plug: Testing and Inspection

Spark Plug Inspection/Replacement

1. Remove the spark plugs, and note which cylinder each one came from.




2. Inspect the electrodes and ceramic insulator.

Burned or worn electrodes may be caused by:
- Advanced ignition timing
- Loose spark plug
- Insufficient cooling

Fouled plug may be caused by:
- Retarded ignition timing
- Oil in combustion chamber
- Incorrect spark plug gap
- Excessive idling/low speed running
- Clogged air cleaner element
- Deteriorated ignition coil




3. Do not adjust the gap of iridium tip plugs (A); replace the spark plug if the gap is out of specification.

Electrode Gap:
Standard (New): 1.0 - 1.1 mm (0.039 - 0.043 in.)
Service Limit: 1.3 mm (0.051 in.)




4. Replace the plug at the specified interval, or if the center electrode is rounded (A).




5. If spark plugs need to be replaced, select the spark plugs according to the designation on the cylinder head and the table shown.
6. Apply a small quantity of anti-seize compound to the plug threads, and screw the plugs into the cylinder head finger-tight. The torque them to 23 N.m (2.3 kgf.m,17 lbf.ft).

NOTE: If a spark plug is to be reused, use it in the cylinder where the plug was originally located.