SPARK PLUG CHECK AND CLEANING

caution

Never attempt to adjust the gap of the iridium plug.
Do not attempt to clean the iridium plug using a wire brush because it may result in damage to the electrode. When the iridium plug is cleaned, special tool spark plug brush (MB992273).

note

Obey the maintenance interval of the relevant vehicle for the spark plug replacement. If the plug gap and insulation resistance are normal, check the plug condition and clean if necessary.

SPARK PLUG GAP CHECK

Check the plug gap with the wire type plug gap gauge. Replace it if the limit is exceeded.
Standard value, limit:

<4B1>

Manufacturer
Type
Standard value (mm)
Limit (mm)

NGK
<4B11> FR6EI
<4B12> FR5EI
0.7 - 0.8
1.2

DENSO
<4B11> K20PSR-B8
<4B12> K16PSR-B8
0.7 - 0.8
1.2

<4J1>

Manufacturer
Type
Standard value (mm)
Limit (mm)

NGK
DILKR6D11G
1.0 - 1.1
1.3

SPARK PLUG INSULATION RESISTANCE CHECK

1.Measure the insulation resistance of the spark plug. If the insulation resistance of the spark plug is under the limited value, clean the spark plug (Refer to

).
2.After cleaning, measure the insulation resistance again. Replace the plug unless it is within the limited value.
Limit: Minimum 10 MΩ

SPARK PLUG CLEANING

1.Sufficiently apply the brake cleaner to the plug end.

note

Repeatedly applying the brake cleaner is acceptable during the cleaning.

2.Using special tool spark plug brush (MB992273), intensively clean the electrode for 1 to 2 minutes.

note

Even if using strong force, the electrode is not damaged.

note

In case of insufficient cleaning, it is permissible to take longer than 2 minutes for cleaning.

3.After the cleaning, sufficiently remove and then dry both of the carbon and the brake cleaner on the plug, using a waste cloth or air blowing.