Toyota Supra 1990 Manual page 341

Ground
IGNITION SYSTEM - On-Vehicle Inspection (7M-GE)
IG-7
Megger
o
IG0147
IG0598
IG0148
IG0598
INSPECTION OF SPARK PLUGS
NOTICE:
• Never use a wire brush for cleaning.
• Never attempt to adjust the gap on a used plug .
• Spark plugs should be replaced every
60.000
miles
(100.000
kml.
1 . INSPECT ELECTRODE
If using a megger (insulation resistance meter):
(a) Remove the high-tension cords. (See page IG-6)
(b) Measure the insulation resistance.
Correct insulation resistance: More than 10 Mn
If less than 10 Mn. proceed to step 2.
If not using a megger:
(a) Quickly race the engine to 4.000 rpm five times.
(b) Remove the spark plugs. (See procedure below)
(c) Visually inspect the spark plugs.
If the electrode is dry ...... Okay
If the electrode is wet.. ... Proceed to step 3
2. REMOVE SPARK PLUGS
(a) Remove the high-tension cords. (See page IG-6)
(b) Using a plug wrench(16 mm), remove the spark plugs.