## Ignition System

#### Spark Plug Inspection

4-25

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

1. Cracked insulator
2. Damaged gasket
3. Worn or deformed electrodes
4. Improper gap

   Oil-fouling

   Carbon deposits

   Cracked centre electrode insulator

2. Do not adjust the gap of platinum 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 (0.05 in.)

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

Spark Plugs:

Engine Type | Spark Plug Type
D14Z5, D15Y6, D15Y4, D16W7 | ZFR5J-11 (NGK) KJ16CR-L11 (DENSO)
D15Y5, D17A1, D17A2, D17Z1, D17Z4 | ZFR6J-11 (NGK) KJ20CR-L11 (DENSO)
D17A5 | BKR6E-N11 (NGK) K20PR-L11 (DENSO)
D15Y2, D15Y3, D16V2, D16W8 | BKR5E-11 (NGK) K16CR-L11 (DENSO)
D17Z2, D17Z3 | ZFR6J-11 (NGK) ZFR7J-11 (NGK) KJ20CR-L11 (DENSO) KJ22CR-L11 (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 Nm (1.8 kgf/m, 13 lbf/ft).