Acura NSX 1991 Manual page 764

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Ignition System
Spark Plug Inspection
1. Inspect the electrodes and ceramic insulator for:
Worn or deformed
electrodes
Damaged
gasket
Cracked
insulator
Burned or worn electrodes may be caused by:
• Advanced ignition timing
• Loose spark plug
• Plug heat range too low
• Insufficient cooling
Fouled plug may be caused by:
Retarded ignition timing
Oil in combustion chamber
Incorrect spark plug gap
Plug heat range too high
Excessive idling/low speed running
Clogged air cleaner element
Deteriorated ignition coil
Table of Contents
2.
Spark Plug:
• Improper gap
• Oil-fouling
• Carbon deposits
3.
• Cracked center
electrode insulator
Electrode Gap:
4.
Replace the plug if it is fouled or worn.
NOTE: Do not use spark plugs other than those
listed below.
PFR6N-11 (NGK)
PK20PR-L11 (Nippondenso)
Make sure that the 1.3 mm (0.051 in) plug gauge
does not go into the gap for the platinum tip plug. If
the gauge goes into the gap, do not attempt to ad-
just the side electrode; replace the plug with a new
one.
Platinum tip plug:
Check and confirm that the
1.3 mm (0.051 in) plug
gauge does not go into the
gap.
Screw the plugs into the cylinder head finger-tight,
then torque them to 18 N-m (1.8 kg-m, 13 Ib-ft).
NOTE: Apply a small quantity of anti-seize com-
pound to the plug threads before installing each
plug.
Anti-seize compound
applied to threads