1991 MITSUBISHI MONTERO reset

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

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

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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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

incorrect index, see FUEL
SYSTEMS
Hot fast idle RPM too low Reset fast idle RPM,
see TUNE-UP









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BASIC HOT START SYMPTOMS TROUBLE SHOOTING CHART








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CONDITION POSSIBLE CAUSE CORRECTION








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Engine Won't Engine flooded Allow fuel to
Start evaporate









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BASIC COLD ENGINE DRIVEABILITY SYMPTOMS TROUBLE SHOOTING CHART








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CONDITION POSSIBLE CAUSE CORRECTION








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Engine Stalls in Choke vacuum kick setting Reset choke vacuum
Gear incorrect kick, see FUEL
SYSTEMS
Fast idle RPM incorrect Reset fast idle RPM,
see TUNE-UP
Fast idle cam index Reset fast idle cam
incorrect see FUEL SYSTEMS









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Acceleration Sag Defective choke control Replace choke
or Stall switch control switch
Choke vacuum kick setting Reset choke vacuum
incorrect kick see, FUEL
SYSTEMS
Float level incorrect Adjust float level,
(too low) FUEL SYSTEMS
Accelerator pump defective Repair or replace
pump see FUEL
SYSTEMS
Secondary throttles not Inspect lockout
closed adjustment,see FUEL
SYSTEMS









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Sag or Stall Defective choke control Replace choke
After Warmup switch control switch, see
FUEL SYSTEMS
Defective accelerator pump Replace pump, see
FUEL SYSTEMS
Float level incorrect Adjust float level,
(too low) see FUEL SYSTEMS









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Backfiring & Plugged heat crossover Remove restriction
Black Smoke system









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BASIC WARM ENGINE DRIVEABILITY SYMPTOMS TROUBLE SHOOTING CHART








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CONDITION POSSIBLE CAUSE CORRECTION








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Hesitation With Vacuum leak Inspect vacuum lines
Small Amount of
Gas Pedal Movement
Accelerator pump weak or Replace pump, see
inoperable FUEL SYSTEMS
Float level setting too low Reset float level,
see,FUEL SYSTEMS
Metering rods sticking or Inspect and/or
binding replace rods, see
FUEL SYSTEMS
Carburetor idle or transfer Inspect system and
system plugged remove restriction
Frozen or binding heated air Inspect heated air
inlet door for binding









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Hesitation With Defective accelerator pump Replace pump, see
Heavy Gas Pedal FUEL SYSTEMS
Movement
Metering rod carrier Remove restriction
sticking or binding
Large vacuum leak Inspect vacuum
system and repair
leak
Float level setting too Reset float level,
low see FUEL SYSTEMS
Defective fuel pump, lines Inspect pump, lines
or filter and filter
Air door setting incorrect Adjust air door
setting, see FUEL









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DIESEL ENGINE 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.
NOTE: Diesel engines mechanical diagnosis is the same as gasoline
engines for items such as noisy valves, bearings, pistons,
etc. The following trouble shooting covers only items
pertaining to diesel engines.
BASIC DIESEL ENGINE TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Engine Won't Bad battery connections Check connections
Crank or dead batteries and/or replace

batteries
Bad starter connections Check connections
or bad starter and/or replace
batteries









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Engine Cranks Bad battery connections Check connections
Slowly, Won't or dead batteries and/or replace
Start batteries
Engine oil too heavy Replace engine oil









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Engine Cranks Glow plugs not functioning Check glow plug system,
Normally, But see FUEL SYSTEMS
Will Not Start Glow plug control not Check controller, see
functioning FUEL SYSTEMS
Fuel not injected into Check fuel injectors,
cylinders see FUEL SYSTEMS
No fuel to injection pump Check fuel delivery
system
Fuel filter blocked Replace fuel filter
Fuel tank filter blocked Replace fuel tank
filter
Fuel pump not operating Check pump operation
and/or replace pump
Fuel return system blocked Inspect system and
remove restriction
No voltage to fuel solenoid Check solenoid and
connections
Incorrect or contaminated Replace fuel
fuel
Incorrect injection pump Re-adjust pump timing,
timing see FUEL SYSTEMS
Low compression Check valves, pistons,
rings, see ENGINES
Injection pump malfunction Inspect and/or replace
injection pump









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Engine Starts, Incorrect slow idle Reset idle adjustment,
Won't Idle adjustment see TUNE-UP
Fast idle solenoid Check solenoid and
malfunctioning connections
Fuel return system blocked Check system and remove
restrictions
Glow plugs go off too soon See glow plug diagnosis
in FUEL SYSTEMS
Injection pump timing Reset pump timing, see
incorrect FUEL SYSTEMS
No fuel to injection pump Check fuel delivery
system
Incorrect or contaminated Replace fuel
fuel
Low compression Check valves, piston,
rings, see ENGINES
Injection pump malfunction Replace injection pump,
see FUEL SYSTEMS
Fuel solenoid closes in RUN Check solenoid and
position connections









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Engines Starts/ Incorrect slow idle Reset slow idle, see
Idles Rough W/out adjustment TUNE-UP
Smoke or Noise Injection line fuel leaks Check lines and
connections
Fuel return system blocked Check lines and
connections

Air in fuel system Bleed air from system
Incorrect or contaminated Replace fuel
fuel
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS









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Engines Starts Injection pump timing Reset pump timing, see
and Idles Rough incorrect FUEL SYSTEMS
W/out Smoke or Engine not fully broken in Put more miles on
Noise, But Clears engine
After Warm-Up Air in system Bleed air from system
Injector nozzle malfunction Check nozzles, see
FUEL SYSTEMS









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Engine Idles Blocked fuel filter Replace fuel filter
Correctly, Injection pump timing Reset pump timing, see
Misfires Above incorrect FUEL SYSTEMS
Idle Incorrect or contaminated Replace fuel
fuel









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Engine Won't Fast idle adjustment Reset fast idle, see
Return To Idle incorrect TUNE-UP
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS
External linkage binding Check linkage and
remove binding









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Fuel Leaks On Loose or broken fuel line Check lines and
Ground connections
Internal injection pump Replace injection pump,
seal leak see FUEL SYSTEMS









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Cylinder Injector nozzles sticking Test injectors, see
Knocking Noise open FUEL SYSTEMS
Very low nozzle opening Test injectors and/or
pressure replace









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Loss of Engine Restricted air intake Remove restriction
Power EGR valve malfunction Replace EGR valve
Blocked or damaged exhaust Remove restriction
system and/or replace
components
Blocked fuel tank filter Replace filter
Restricted fuel filter Remove restriction
and/or replace filter
Block vent in gas cap Remove restriction
and/or replace cap
Tank-to-injection pump fuel Check fuel lines and
supply blocked connections
Blocked fuel return system Remove restriction
Incorrect or contaminated Replace fuel
fuel
Blocked injector nozzles Check nozzle for
blockage, see FUEL
SYSTEMS
Low compression Check valves, rings,
pistons, see ENGINES









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Loud Engine Basic timing incorrect Reset timing, see
Noise With Black FUEL SYSTEMS
Smoke EGR valve malfunction Replace EGR valve
Internal injection pump Replace injection pump,
malfunction see FUEL SYSTEMS