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1.2L REVOTRON ENGINE
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Inspection :
The condition of the spark plug provides a
good indication of the engine running
condition. Knowing what to look for can
provide insight to operating conditions and
help to pinpoint problems with operation.
"Read" the spark plug to determine engine
operating condition.
1.
Normal -
The spark plug core will be
lightly coated with grey or brown
deposits. Heavy deposits indicate the use of
fuel or oiladditives. The electrode will not be
worn excessively or nicked. The gap will
only increase 0.01 mm for every 2000 km of
use with the correct fuel. Clean and reuse if
replacement is not required.
2.
Carbon Fouling -
Dark sooty deposits will
be present on the entire spark plug. This
may cause the electrode to short-circuit,
weakening or eliminating spark. Typically
caused by excess fuel from a leaking fuel
injector, sticking idle speed control valve, or
a clogged air filter. Replace the spark plugs
if carbon fouled.
3.
Oil Fouling-
Heavy wet deposits indicate
the spark plug is oil fouled. Oil fouling occurs
when engine oil is entering the combustion
chamber from defective piston rings, valve
guides or seals, or a blown head gasket. May
also occur during run-in/break In on new or
overhauled engines. Replace the spark plugs
if oil fouled.
4.
Overheating-
Overheating is typically
caused by the over-advancement of
ignition timing, a lean fuel mixture,
incorrect spark plug heat range, or incorrect
fuel octane rating. Electrodes and insulator
will be white and may show signs of wear.
Replace overheated spark plugs.
5.
Detonation
- A detonation or pre-ignition
condition will look the similar to an
overheating condition, but wear and
damage will be much worse such as
insulator cracking or breaking. Typically
caused by the wrong grade of fuel,
incorrect spark plug heat range, or an
extremely lean condition. The problem must
be identified and repaired immediately
otherwise severe engine damage will occur.
Do not reuse broken or cracked spark plugs.