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 iridium tip plugs; replace the spark plug if the gap is out of specification.

Electrode Gap
Except LX-SULEV, EX-SULEV, EX-L-SULEV:
Standard (New): 1.0 - 1.1 mm (0.039 - 0.043 in.)
LX-SULEV, EX-SULEV, EX-L-SULEV:
Standard (New): 1.2 - 1.3 mm (0.047 - 0.051 in.)




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

Spark Plugs
Except LX-SULEV EX-SULEV, EX-L-SULEV:
IZFR6K11 (NGK)
SKJ20DR-M11 (DENSO)
LX-SULEV, EX-SULEV, EX-L-SULEV:
IZFR6K13 (NGK)
SKJ20DR-M13 (DENSO)

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).