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8-6
DI~GNOSIS
GUIDE (Continued)
ENGINE DOES NOT DEVELOP
FULL POWER, OR HAS POOR
HIGH SPEED PERFORMANCE
(Continued)
EXCESSIVE FUEL
CONSUMPTION
ENGINE OVERHEATS
GROUP 8-
ENGINE
EXHAUST SYSTEM
Restriction in system.
COOLING SYSTEM
Thermostat inoperative
or
of in-
correct heat range.
Thermostat installed incorrectly.
Check the cooling system for in-
ternal leakage
and/ or
for a condi-
tion that prevents the engine from
reaching normal
operating
temper-
ature.
Determine the
actual
fuel con·
sumption with test
equipment
in-
stalled in the car.
If the test indicates that the fuel
consumption is not
excessive,
dem-
onstrate to
the
owner
how improper
driving
habits
will
affect fuel con-
sumption.
If
the
test
indicates
that
the fuel
consumption is excessive, make a
preliminary check of the following
items before proceeding to the fuel
and
ignition systems.
PRELIMINARY CHECKS
CHASSIS
ITEMS
Check:
Tyres for proper pressure.
Front wheel
alignment.
Brake
adjustment.
EXHAUST SYSTEM
System restricted.
ODOMETER
Check calibration.
IGNITION
SYSTEM
Check:
Distributor breaker points.
Ig-nition timing.
EN<:INE
Crankt-ase
ventilation
regulator
valvt• defedive or restrided tubes
(Positive
Crankcase
Ventilation Sy-
,;tcm).
FINAL CHECKS
FUEL SYSTEM
Che<·k:
Fuel pump
prt'ssure.
E11;.rine idlt•
speed.
Idle fuel mixture needlt'(s) for
prc:>per adjustment.
TEMPERATURE SENDING
UNIT AND GAUGE
Unit or c:aug·e defective (not in-
di<·ating correct
constant volta).!.'t'
tive.
ENGINE
temperatures)
ot·
regulator
defec.
Cylinder head bolts not properly
tm·qued.
Incorrect valve
clearance.
Low oil level or im·on·ect viscos-
ity oil used
.
COOLING
SYSTEM
Insufficient coolant.
ENGINE
Perform a manifold vacuum or
engine compression test to deter-
mine which mechanical component
of
the engine is at fault.
One or more camshaft lobes worn
beyond wear limit.
Worn valve guides.
Positive crankcase ventilation sy-
stem not operating properly.
TRANSMISSION
Improper band adjustment (auto-
matic transmissions).
Automatic choke for proper op-
eration.
Fast idle speed screw for proper
adjustment.
Accelerating pump stroke adjust-
ment.
Air cleaner for restrictions.
J:.,loat setting or fuel level.
Jets for wear and/or damage.
Power valve operation.
Air bleeds for obstructions.
Accelerating
pump
discharge
nozzles for siphoning.
Accelerator linkage for binds.
Choke adjustment.
IGNITION SYSTEM
Check
:
Ignition timing.
Spark plug condition and adjust-
ment.
Distributor
spark
advance opera-
tion.
ENGINE
Pel'form a manifold vacuum or
engine compression test to detel'·
mine which met·hanical
component
of the engine
is
at fault.
Check
valve clearance
.
COOLIN(; SYSTEM
Check
thermostat
operation
and
heat
range.
TRANSMISSION
Cht'ck
han<l
adjustment
(auto-
mali<- transmissions)
.
Coolin)!
system
leaks.
Orin·
helt tension
incorrect.
Radiator fins obstructed.
Thennostat
defective.
Thermostat improperly
installed.
Cooling systl'm
passages blocked.
Water pump inoperative.
IGNITION
SYSTEM
lnt·ot..-ect ignition
timing.
I nco. rect distributor
advance.
EXHAUST
SYSTEM
Restl'ictions
in
system.
BRAKES
ImpropE-r adjustment-too
tig·ht.
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