Spark Plug: Testing and Inspection

Spark Plug Inspection




1. Inspect the electrodes and ceramic insulator.

Burned or worn electrodes may be caused by:

- Advanced ignition timing
- Loose spark plug
- Plug heat range too hot
- Insufficient cooling

Fouled plug may be caused by:

- Retarded ignition timing
- Oil in combustion chamber
- Incorrect spark plug gap
- Plug heat range too cold
- Excessive idling/low speed running
- Clogged air cleaner element
- Deteriorated ignition coils




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

Electrode Gap:
Standard (New): 1.0 - 1.1 mm (0.039 - 0.04 in.)




3. Replace the plug at the specified interval or if the center electrode is rounded (A). Use only the spark plugs listed below.

Spark Plugs:
NGK: IZFR5K-11
DENSO: SKJ16DR-M11

4. Apply a small quantity of anti-seize compound to the plug threads, and screw the plugs into the cylinder head finger-tight. Then torque them to 18 N.m(1.8 kgf.m, 13 lbf.ft).