SPARK PLUG CHECK AND CLEANING <134, 135>


<When the spark plugs are nickel plug (FR7SE)>
note Obey the maintenance interval of the relevant vehicle for the spark plug replacement. Unless the plug is remarkably burned or worn, and insulator plug is damaged, adjust the plug gap and check the plug state. Clean the plug if necessary.
1.Check that the plug is not burned, that the insulator plug is not damaged, and that the seizure state is good.
2.If cleaning is required due to carbon deposits, etc., clean using a plug cleaner or wire brush, etc.

3.Check the plug gap using a plug gap gauge, and adjust if not within the standard value.

Standard value:
Manufacturer
 Type
 Standard value (mm)
BOSCH
 FR7SE
 1.0 - 1.1

<When the spark plugs are platinum plug (FR7NPP33)>

caution
  • Never attempt to adjust the gap of the platinum plug.
  • Do not attempt to clean the platinum plug using a wire brush because it may result in damage to the electrode. When the platinum plug is cleaned, use a plug cleaner, sand blast type, or 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:
Manufacturer
 Type
 Standard value (mm)
 Limit (mm)
BOSCH
 FR7NPP33
 1.0 - 1.1
 1.3

SPARK PLUG INSULATION RESISTANCE CHECK

1.Measure the insulation resistance. If the insulation resistance of the spark plug is under the limited value, clean the plug within 20 seconds using a plug cleaner.
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
note Using a sand blast type plug cleaner, is recommended for the spark plug cleaning.
<When a sand blast type plug cleaner is used>
    Cleaning must be carried out within 20 seconds to protect the electrode.

<When special tool MB992273 is used>
  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 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.