Montero LS 4WD V6-2972cc 3.0L SOHC 12 Valve (1994)
Spark Plug: Testing and Inspection
Spark Plug Visual Inspection
INSPECTION AND CLEANING
Inspection
Check the following items to see that electrodes are not burnt, insulators and not broken, and to what extent the porcelain insulator is burnt.
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Broken insulators
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Warning electrodes
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Deposited carbon
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Damaged or broken gasket
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Burnt condition of porcelain insulator at spark gap.
Dark deposit of carbon indicates too rich a fuel mixture or extremely low air intake. Also, misfiring due to excessive spark gap is suspected. White
burning indicates too lean a fuel mixture of excessively advanced ignition timing. Also insufficient plug tightening is suspected.
Cleaning
For cleaning, use a plug cleaner or wire brush. Clean the porcelain insulator above the shell as well.
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Clean with a plug cleaner. Use an air gun to remove the dust which is deposited on plug threads.
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Use a plug gap gage to check the plug gap, and adjust the gap if it is not at the standard value.
Check the plug gap and replace if the limit is exceeded.
Standard value: 1.0 - 1.1 mm (0.039 - 0.043 in.)
Limit: 1.3 mm (0.051 in.)
Specified torque: 25 Nm (15 ft.lbs.)