engine JEEP CHEROKEE 1988 Service Repair Manual
[x] Cancel search | Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
Page 1229 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual \
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Starter Drive Starter motor loose on](/img/16/57037/w960_57037-1228.png "JEEP CHEROKEE 1988 Service Repair Manual \
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Starter Drive Starter motor loose on")
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Starter Drive Starter motor loose on Tighten starter
Will Not mountings attach bolts
Disengage
Worn drive end bushing See STARTER article
Damaged engine flywheel Replace flywheel and
teeth starter pinion gear for
damage
Drive yolk return spring Replace return spring
broken or missing
Faulty ignition switch Replace ignition switch
Insufficient clearance Replace starter
between winding leads to solenoid
solenoid terminal and main
contact in solenoid
Starter clutch not Replace starter clutch
disengaging
Ignition starter switch Replace ignition switch
contacts sticking
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Starter Relay Faulty solenoid switch, Check all wiring
Operates but switch connections or between relay and
Solenoid Does Not solenoid or replace
relay or solenoid as
necessary
Broken lead or loose Repair wire or wire
soldered connections connections as
necessary
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Solenoid Plunger Weak battery Charge or replace
Vibrates When battery as necessary
Switch is Engaged
Solenoid contacts Clean contacts or
corroded replace solenoid
Faulty wiring Check all wiring
leading to solenoid
Broken connections inside Repair connections or
switch cover replace solenoid
Open hold-in wire Replace solenoid
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Low Current Draw Worn brushes or weak Replace brushes or
brush springs as
necessary
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High Pitched Whine Distance too great Align starter or check
During Cranking between starter that correct starter
Before Engine pinion and flywheel and flywheel are being
Fires but Engine used
Fires and Cranks
Normally
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High Pitched Distance too small between
Whine After Engine starter pinion and flywheel
Page 1230 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual Fires With Key Flywheel runout contributes
released. Engine to the intermittent nature
Fires and Cranks
Normally
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\](/img/16/57037/w960_57037-1229.png "JEEP CHEROKEE 1988 Service Repair Manual Fires With Key Flywheel runout contributes
released. Engine to the intermittent nature
Fires and Cranks
Normally
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Fires With Key Flywheel runout contributes
released. Engine to the intermittent nature
Fires and Cranks
Normally
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AIR CONDITIONING & HEAT
AIR CONDITIONING TROUBLE SHOOTING
WARNING: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC AIR CONDITIONING TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE \
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Compressor Not Working
Compressor clutch circuit open.
Compressor clutch coil inoperative.
Poor clutch ground connection.
Fan belts loose.
Thermostatic switch inoperative.
Thermostatic switch not adjusted.
Ambient temperature switch open.
Superheat fuse blown. \
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Excessive Noise or Vibration
Missing or loose mounting bolts.
Bad idler pulley bearings.
Fan belts not tightened correctly.
Compressor clutch contacting body.
Excessive system pressure.
Compressor oil level low.
Damaged clutch bearings.
Damaged reed valves.
Damaged compressor. \
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Insufficient or No Cooling;
Compressor Working
Expansion valve inoperative.
Heater control valve stuck open.
Low system pressure.
Blocked condenser fins.
Blocked evaporator fins.
Vacuum system leak.
Vacuum motors inoperative.
Control cables improperly adjusted.
Restricted air inlet.
Mode doors binding.
Blower motor inoperative.
Temperature above system capacity. \
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HEATER SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
Page 1234 of 1378
Parking Brake cables frozen See DRUM BRAKES
BRAKE SYSTEM
Incorrect installation of
inboard disc pad Remove and replace
correctly
Power booster output
rod too long See POWER BRAKE UNITS
BRAKE SYSTEM
Brake pedal not returning See DISC, DRUM BRAKES
freely BRAKE SYSTEM
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Brakes Grab or
Uneven Braking
Action Malfunction of combination See CONTROL VALVE or
valve BRAKE SYSTEM
Malfunction of power brake See POWER BRAKE UNITS
unit or BRAKE SYSTEM
Binding brake pedal See DISC, DRUM BRAKES
or BRAKE SYSTEM
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Pulsation or
Roughness Uneven pad wear caused by See DISC BRAKES or
caliper BRAKE SYSTEM
Uneven rotor wear See DISC BRAKES or
BRAKE SYSTEM
Drums out-of-round Reface or replace drums
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ENGINE MECHANICAL
COOLING SYSTEM TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
COOLING SYSTEM TROUBLE SHOOTING
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CONDITION POSSIBLE CAUSE CORRECTION \
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Overheating Coolant Leak Fill/Pressure Test
System
A/C Condenser Fins Clogged Remove/Clean Condenser
Radiator Fins Clogged Remove/Clean Radiator
Thermostat Stuck Closed Replace Thermostat
Clogged Cooling System
Passages Clean/Flush Cooling
System
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Water Pump Malfunction Replace Water Pump
Fan Clutch Malfunction Replace Fan Clutch
Retarded Ignition Timing Reset Ignition Timing
Cooling Fan Malfunction Test Cooling Fan/
Circuit
Cooling Fan Motor
Malfunction Test Fan Motor
Cooling Fan Relay
Malfunction Test Fan Relay
Faulty Radiator Cap Replace Radiator Cap
Broken/Slipping Fan Belt Replace Fan Belt
Restricted Exhaust Repair Exhaust System
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Corrosion Impurities In Coolant Clean/Flush System \
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Coolant Leakage Damaged hose Replace Hose
Leaky Water Pump Replace Water Pump
Damaged Radiator Seam Replace/Repair Radiator
Leaky Thermostat Cover Replace Thermostat
Cover
Cylinder Head Problem Check Head/Head Gasket
Leaky Freeze Plugs Replace Freeze Plugs
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Recovery System Inoperative
Loose and/or Defective
Radiator Cap Replace Radiator Cap
Overflow Tube Clogged
and/or Leaking Repair Tube
Recovery Bottle Vent
Restricted Clean Vent
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No Heater Core Flow
Collapsed Heater Hose Replace Heater Hose
Plugged Heater Core Clean/Replace Heater
Core
Faulty Heater Valve Replace Heater Valve
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GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
Page 1236 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual in the section(s) you are accessing.
BASIC GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING CHART
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BASIC GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING CHART
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in the section(s) you are accessing.
BASIC GASOLINE ENGINE - MECHANICAL TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE CORRECTION \
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Engine Lopes At Intake manifold-to-head Replace manifold
Idle leaks gasket, See ENGINES
Blown head gasket Replace head gasket,
See ENGINES
Worn timing gears, chain Replace gears, chain or
or sprocket sprocket
Worn camshaft lobes Replace camshaft, See
ENGINES
Overheated engine Check cooling system,
See COOLING
Blocked crankcase vent Remove restriction
valve
Leaking EGR valve Repair leak and/or
replace valve
Faulty fuel pump Replace fuel pump
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Engine Has Low Leaking fuel pump Repair leak and/or
Power replace fuel pump
Excessive piston-to-bore Install larger pistons,
clearance See ENGINES
Sticking valves or weak Check valve train
valve springs components, See ENGINES
Incorrect valve timing Reset valve timing, See
ENGINES
Worn camshaft lobes Replace camshaft, See
ENGINES
Blown head gasket Replace head gasket.
See ENGINES.
Clutch slipping Adjust pedal and/or
replace components, See
ENGINES
Engine overheating Check cooling system,
See COOLING
Auto. Trans. pressure
regulator valve faulty Replace pressure
regulator valve
Auto. Trans. fluid level Add fluid as necessary
too low
Improper vacuum diverter
valve operation Replace vacuum diverter
valve
Vacuum leaks Inspect vacuum system
and repair as required
Leaking piston rings Replace piston rings,
See ENGINES
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Faulty High Low fuel pump volume Replace fuel pump
Speed Operation
Leaking valves or worn Replace valves and/or
springs, See ENGINES
Incorrect valve timing Reset valve timing,See
ENGINES
Intake manifold restricted Remove restriction
Worn distributor shaft Replace distributor
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Faulty Improper fuel pump stroke Remove pump and reset
Acceleration pump stroke
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Incorrect ignition timing Reset ignition timing,
See TUNE-UP
Leaking valves Replace valves, See
ENGINES
Worn fuel pump diaphragm Replace diaphragm or
or piston piston
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Intake Backfire Improper ignition timing Reset ignition timing,
See TUNE-UP
Faulty accelerator pump Replace accelerator
discharge pump
Improper choke operation Check choke and adjust
as required
Defective EGR valve Replace EGR valve
Fuel mixture too lean Reset air/fuel mixture,
See TUNE-UP
Choke valve initial Reset choke valve
clearance too large initial clearance
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Exhaust Backfire Vacuum leak Inspect and repair
vacuum system
Faulty vacuum diverter Replace vacuum diverter
valve valve
Faulty choke operation Check choke and adjust
as required
Exhaust system leak repair exhaust system
leak
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Engine Ignition timing too far Reset ignition timing,
Detonation advanced See TUNE-UP
Faulty ignition system Check ignition timing,
See TUNE-UP
Spark plugs loose or Retighten or replace
faulty plugs
Fuel delivery system Inspect lines, pump and
clogged filter for clog
EGR valve inoperative Replace EGR valve
PCV system inoperative Inspect and/or replace
hoses or valve
Vacuum leaks Check vacuum system and
repair leaks
Excessive combustion
chamber deposits Remove built-up
deposits
Leaking, sticking or Inspect and/or replace
broken valves valves
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External Oil Fuel pump improperly seated Remove pump, replace
Leakage or worn gasket gasket and seat
properly
Oil pan gasket broken or Straighten pan and
pan bent replace gasket
Timing chain cover gasket Replace timing chain
broken cover gasket
Rear main oil seal worn Replace rear main oil
seal
Oil pan drain plug not Remove and reinstall
seated properly drain plug
Camshaft bearing drain Remove restriction
hole blocked
Oil pressure sending Remove and reinstall
switch leaking sending switch
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Excessive Oil Worn valve stems or guides Replace stems or
Consumption guides, See ENGINES
Valve "O" ring seals Replace "O" ring seals,
damaged See ENGINES
Plugged oil drain back holes Remove restrictions
Improper PCV valve Replace PCV valve
operation
Engine oil level too high Remove excess oil
Engine oil too thin Replace thicker oil
Valve stem oil deflectors Replace oil deflectors
damaged
Incorrect piston rings Replace piston rings,
See ENGINES
Piston ring gaps not Reinstall piston rings,
staggered See ENGINES
Insufficient piston ring Replace rings, See
tension ENGINES
Piston ring grooves or oil Replace piston rings,
return slots clogged See ENGINES
Piston rings sticking in Replace piston rings,
grooves See ENGINES
Piston ring grooves Replace piston and
excessively worn rings, See ENGINES
Compression rings installed Replace compression
upside down rings correctly, See
ENGINES
Worn or scored cylinder Rebore cylinders or
walls replace block
Mismatched oil ring Replace oil ring
expander and rail expander and rail, See
ENGINES
Intake gasket dowels too Replace intake gasket
long dowels
Excessive main or connecting Replace main or
rod bearing clearance connecting rod
bearings, See ENGINES
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No Oil Pressure Low oil level Add oil to proper level
Oil pressure sender or Replace sender or gauge
gauge broken
Oil pump malfunction Remove and overhaul oil
pump, See ENGINES
Oil pressure relief valve Remove and reinstall
sticking valve
Oil pump passages blocked Overhaul oil pump, See
ENGINES
Oil pickup screen or tube remove restriction
blocked
Loose oil inlet tube Tighten oil inlet tube
Loose camshaft bearings Replace camshaft
bearings, See ENGINES
Internal leakage at oil Replace block or
passages cylinder head
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Low Oil Pressure Low engine oil level Add oil to proper level
Engine oil too thin Remove and replace with
thicker oil
Excessive oil pump Reduce oil pump
clearance clearance, See ENGINES
Oil pickup tube or screen Remove restrictions
blocked
Main, rod or cam bearing Replace bearing to
clearance excessive reduce clearance, See
Page 1239 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual ENGINES \
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ENGINES \
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High Oil Improper grade of oil Replace with proper oil
Pressure Oil pressure relief valve Eliminate binding
stuck closed
Oil pressure sender or Replace sender or gauge
gauge faulty
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Noisy Main Inadequate oil supply Check oil delivery to
Bearings main bearings
Excessive main bearing Replace main bearings,
clearance See ENGINES
Excessive crankshaft end Replace crankshaft, See
play ENGINES
Loose flywheel or torque Tighten attaching bolts
converter
Loose or damaged vibration Tighten or replace
damper vibration damper
Crankshaft journals Re-grind crankshaft
out-of-round journals
Excessive belt tension Loosen belt tension
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Noisy Connecting Excessive bearing clearance Replace bearing, See
Rods or missing bearing ENGINES
Crankshaft rod journal Re-grind crankshaft
out-of-round journal
Misaligned connecting rod Remove rod or cap and
or cap realign
Incorrectly tightened rod Remove and re-tighten
bolts rod bolts
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Noisy Pistons Excessive piston-to-bore Install larger pistons,
and Rings clearance See ENGINES
Bore tapered or out-of-round Rebore block
Piston ring broken Replace piston rings,
See ENGINES
Piston pin loose or seized Replace piston pin, See
ENGINES
Connecting rods misaligned Realign connecting rods
Ring side clearance too Replace with larger or
loose or tight smaller rings
Carbon build-up on piston Remove carbon
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Noisy Valve Worn or bent push rods Replace push rods, See
Train ENGINES
Worn rocker arms or bridged Replace push rods, See
pivots ENGINES
Dirt or chips in valve Remove lifters and
lifters remove dirt/chips
Excessive valve lifter Replace valve lifters,
leak-down See ENGINES
Valve lifter face worn Replace valve lifters,
See ENGINES
Broken or cocked valve replace or reposition
springs springs
Too much valve stem-to-guide Replace valve guides,
clearance See ENGINES
Valve bent Replace valve, See
ENGINES
Loose rocker arms Retighten rocker arms,
See ENGINES
Excessive valve seat Reface valve seats, See
run-out ENGINES
Page 1240 of 1378
Missing valve lock Install new valve lock
Excessively worn camshaft Replace camshaft, See
lobes ENGINES
Plugged valve lifter oil Eliminate restriction
holes or replace lifter
Faulty valve lifter check Replace lifter check
ball ball, See ENGINES
Rocker arm nut installed Remove and reinstall
upside down correctly
Valve lifter incorrect for Remove and replace
engine valve lifters
Faulty push rod seat or Replace plunger or push
lifter plunger rod
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Noisy Valves Improper valve lash Re-adjust valve lash,
See ENGINES
Worn or dirty valve lifters Clean and/or replace
lifters
Worn valve guides Replace valve guides,
See ENGINES
Excessive valve seat or Reface seats or valve
face run-out face
Worn camshaft lobes Replace camshaft, See
ENGINES
Loose rocker arm studs Re-tighten rocker arm
studs, See ENGINES
Bent push rods Replace push rods, See
ENGINES
Broken valve springs Replace valve springs,
See ENGINES
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Burned,Sticking Weak valve springs or Replace valves and/or
or Broken Valves warped valves springs, See ENGINES
Improper lifter clearance Re-adjust clearance or
replace lifters
Worn guides or improper Replace valve guides,
guide clearance See ENGINES
Out-of-round valve seats Re-grind valve seats
or improper seat width
Gum deposits on valve Remove deposits
stems, seats or guides
Improper spark timing Re-adjust spark timing
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Broken Undersize pistons Replace with larger
Pistons/Rings pistons, See ENGINES
Wrong piston rings Replace with correct
rings, See ENGINES
Out-of-round cylinder bore Re-bore cylinder bore
Improper connecting rod Remove and realign
alignment connecting rods
Excessively worn ring Replace pistons, See
grooves ENGINES
Improperly assembled Re-assemble pin-to
piston pins -piston, See ENGINES
Insufficient ring gap Install new rings, See
clearance ENGINES
Engine overheating Check cooling system
Incorrect ignition timing Re-adjust ignition
timing, See TUNE-UP
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Excessive Leaks at manifold to Replace manifold or
Exhaust Noise head, or to pipe pipe gasket
Exhaust manifold Replace exhaust
Page 1241 of 1378
![JEEP CHEROKEE 1988 Service Repair Manual cracked or broken manifold, See ENGINES \
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cracked or broken manifold, See ENGINES \
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ENGINE PERFORMANCE
CARBURETOR TROUBLE SHOOTING:
NOTE: This is GENERAL information. This article is not intended
to be specific to any unique situation or individual vehicle
configuration. The purpose of this Trouble Shooting
information is to provide a list of common causes to
problem symptoms. For model-specific Trouble Shooting,
refer to SUBJECT, DIAGNOSTIC, or TESTING articles available
in the section(s) you are accessing.
BASIC COLD START SYMPTOMS TROUBLE SHOOTING CHART
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CONDITION POSSIBLE CAUSE CORRECTION \
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Engine Won't Choke not closing Check choke
Start operation, see
FUEL SYSTEMS
Choke linkage bent Check linkage, see
FUEL SYSTEM
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Engine Starts, Choke vacuum kick setting Check setting and
Then Dies too wide adjust see, FUEL
SYSTEMS
Fast idle RPM too low Reset RPM to specif-
ication, see TUNE-UP
Fast idle cam index Reset fast idle cam
incorrect index, see FUEL
SYSTEMS
Vacuum leak Inspect vacuum
system for leaks
Low fuel pump outlet Repair or replace
pump, see FUEL
SYSTEMS
Low carburetor fuel level Check float setting
see FUEL SYSTEM
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Engine Quits Choke vacuum kick setting Reset vacuum kick
Under Load incorrect setting,see FUEL
SYSTEMS
Fast idle cam index Reset fast idle cam
incorrect index, see FUEL
SYSTEM
Incorrect hot fast idle Reset fast idle RPM,
speed RPM see TUNE-UP
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Engine Starts, Choke vacuum kick set too Reset vacuum kick,
Runs Up,Then narrow see FUEL SYSTEMS
Idles, Slowly
With Black Smoke Fast idle cam index Reset fast idle cam