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1-8
GROUP
1-
ENGINE AND EXHAUST SYSTEM
ENGINE TROUBLE DIAGNOSIS GUIDE
(Continued)
lar
cylinder,
perform a spark
test
on
ternal
leakage
and/ or
for
a
condi
the
ignition lead
of
that
cylinder.
tion
that
prevents
the
engine
from
ENGINE
RUNS,
BUT
If
a
good
spark
does
not
occur,
reaching
normal
operating
tempera
MISSES
(Continued)
the trouble
is
in
the
secondary
cir
cuit of
the
system.
Check
the
spark
ture.
plug
wire and
the
distributor
cap.
ENGINE
If
a good spark
occurs,
check
the
Perform
a compression
test to
de
spark plug.
If
the
spark
plug
is
not at
termine
which
mechanical
compo
fault,
a mechanical
component of
the
nent of
the
engine
is
at
fault.
engine
is probably
at
fault.
ENGINE
MISSES AT IDLE ONLY
Perform
a compression
test to
de
FUEL
SYSTEM
termine
which
mechanical
compo
Idle fuel
mixture needles not
prop
nent of
the
engine
is
at
fault.
erly
adjusted.
MISSES ERRATICALLY
IGNITION SYSTEM
AT ALL
SPEEDS
Excessive play in
the
distributor
shaft.
EXHAUST
SYSTEM
Worn distributor
cam.
Exhaust
system
restricted.
ENGINE
IGNITION SYSTEM
Perform
a compression
test to
de
Defective
breaker
points,
con
termine
which
mechanical
compo
denser,
secondary
wiring,
coil,
or
nent of
the
engine
is
at
fault.
spark
plugs.
High
tension
leakage
across
the
coil, rotor,
or
distributor
cap.
MISSES
AT
HIGH
SPEED
ONLY
FUEL SYSTEM
Float setting
incorrect.
FUEL
SYSTEM
Fuel
inlet
system
not
operating
Power
valve clogged or
damaged.
properly.
Low
or
erratic
fuel pump
pressure.
Dirt
or water
in fuel lines
or car
Fuel inlet
system
not
operating
buretor.
properly.
Restricted fuel
filter.
Restricted fuel filter.
COOLING SYSTEM
COOLING SYSTEM
Check
the
cooling
system
for
in-
Engine
overheating.
FUEL
SYSTEM
IGNITION
SYSTEM
ROUGH
ENGINE
IDLE
Engine idle
speed set
too
low.
Improperly
adjusted
or
defective
Idle fuel
mixture needles
not
prop
breaker
points.
erly
adjusted.
Idle
compensator malfunction.
Fouled
or
improperly
adjusted
Float setting
incorrect.
spark
plugs.
Air leaks between
the carburetor,
Incorrect
ignition
timing.
spacer,
and
the
manifold
and/ or
fit
tings.
Spark
plug
misfiring.
Power
valve
leaking
fuel.
Idle fuel
system air
bleeds
or
fuel
ENGINE
passages
restricted.
Fuel
bleeding
from
the
accelerat
Loose
engine
mounting
bolts
or
ing
pump discharge
nozzles.
worn
insulator.
Secondary
throttle
plates not clos
Cylinder head bolts
not
properly
ing.
Improper secondary
throttle
plate
torqued.
stop
adjustment.
Crankcase
ventilation regulator
Leaking
fuel
pump,
lines,
or
fit
valve
defective
or
a restricted
exhaust
tings.
tube.
CONTINUED ON NEXT PAGE
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