1991 MITSUBISHI MONTERO oil

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

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

Incorrect injector pump Check pressure, see
housing pressure FUEL SYSTEMS









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Engine Cooling system leaks Check cooling system
Overheating and repair leaks
Belt slipping or damaged Check tension and/or
replace belt
Thermostat stuck closed Remove and replace
thermostat, see
ENGINE COOLING
Head gasket leaking Replace head gasket









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Oil Light on at Low oil pump pressure Check oil pump
Idle operation, see ENGINES
Oil cooler or line Remove restriction
restricted and/or replace cooler









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Engine Won't Injector pump fuel solenoid Remove and check
Shut Off does not return fuel valve solenoid and replace
to OFF position if needed









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VACUUM PUMP DIAGNOSIS
Excessive Noise Loose pump-to-drive Tighten screws
assembly screws
Loose tube on pump assembly Tighten tube
Valves not functioning Replace valves
properly
Oil Leakage Loose end plug Tighten end plug
Bad seal crimp Remove and re-crimp
seal









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FUEL INJECTION 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 FUEL INJECTION TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Engine Won't Cold start valve inoperative Test valve and
Start (Cranks circuit
Normally)
Poor connection;vacuum or Check vacuum and
wiring electrical
connections
Contaminated fuel Test fuel for water
or alcohol
Defective fuel pump relay Test relay and
or circuit wiring
Battery too low Charge and test
battery

Low fuel pressure Test pressure regul-
ator and fuel pump,
check for restricted
lines and filters
No distributor reference Repair ignition
pulses system as necessary
Open coolant temperature Test sensor and
sensor circuit wiring
Shorted W.O.T. switch in Disconnect W.O.T.
T.P.S. switch, engine
should start
Defective ECM Replace ECM
Fuel tank residual pressure Test for fuel
valve leaks pressure drop after
shut down









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Hard Starting Disconnected hot air tube Reconnect tube and
to air cleaner test control valve
Defective Idle Air Control Test valve operation
(IAC) valve and circuit
Shorted, open or misadjusted Test and adjust or
T.P.S. replace T.P.S.
EGR valve open Test EGR valve and
control circuit
Poor Oxygen sensor signal Test for shorted or
circuit
Incorrect mixture from PCV Test PCV for flow,
system check sealing of oil
filter cap









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Poor High Speed Low fuel pump volume Faulty pump or
Operation restricted fuel
lines or filters
Poor MAP sensor signal Test MAP sensor,
vacuum hose and
wiring
Poor Oxygen sensor signal Test for shorted or
open sensor or
circuit
Open coolant temperature Test sensor and
sensor circuit wiring
Faulty ignition operation Check wires for
cracks or poor con-
nections, test
secondary voltage
with oscilloscope
Contaminated fuel Test fuel for water

or alcohol
Intermittent ECM ground Test ECM ground
connection for
resistance
Restricted air cleaner Replace air cleaner
Restricted exhaust system Test for exhaust
manifold back
pressure
Poor MAF sensor signal Check leakage
between sensor and
manifold
Poor VSS signal If tester for ALCL
hook-up is available
check that VSS
reading matches
speedometer









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Ping or Knock on Poor Knock sensor signal Test for shorted or
Acceleration open sensor or
circuit
Poor Baro sensor signal Test for shorted or
open sensor or
circuit
Improper ignition timing See VEHICLE EMISSION
CONTROL LABEL (where
applicable)
Check for engine Low coolant, loose
overheating problems belts or electric
cooling fan
inoperative









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NOTE: For additional electronic fuel injection trouble shooting
information, see the appropriate article in the ENGINE
PERFORMANCE section (not all vehicles have Computer Engine
Control articles). Information is provided there for
diagnosing fuel system problems on vehicles with electronic
fuel injection.
IGNITION 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.
Ignition Secondary Trouble Shooting Chart








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START: Visually inspect Spark Plug Wires, Coil Wires, 

Plug Wire Boots, Rotor, and Distributor Cap for 

signs of damage. 










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OK   NOT OK 




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* To test secondary ignition   * Repair or replace 

system, modify a Spark Plug   damaged components 

by attaching a ground wire   as necessary 

to the body of the plug and  









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widening the gap to 1/4-3/8".

Disconnect spark plug wire 

and insert test plug. Ground 

plug, crank engine, and 

check for spark. 










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GOOD SPARK   NO SPARK 









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* If plug sparks, driveability   * Remove coil wire from the 

problem is most likely NOT   distributor and attach the 

in the ignition system.   modified spark plug. Ground 










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 the plug and crank engine 
 while checking for spark. 









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GOOD SPARK   NO SPARK 









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* If plug has a good spark,   * Proceed to the IGNITION 

the problem is in the plug   PRIMARY TROUBLE SHOOTING 

wires, distributor cap, or   CHECK CHART below in this 

rotor. Replace components   article. 

as necessary.  









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Ignition Primary Trouble Shooting Chart








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START: Visually inspect primary ignition wires for 

broken, frayed, split, or cut wires. Also check 

for loose, corroded, or disconnected connectors. 










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OK   NOT OK 




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* Check that battery voltage   * Repair or replace damaged 

is at least 11.5 volts.   components as necessary. 










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NOT OK   OK 








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* Replace or recharge the   * Check for battery voltage 

battery.   at the positive terminal of 










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 the coil. 









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 OK   NOT OK 




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* Check air Gap of the Pick-Up   * Check resistance of ballast 

coil in the distributor.   resistor (if used) for the 










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 correct resistance value. 
 








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OK   NOT OK  




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* Check Pick-Up coil for   * Adjust or replace as  

correct resistance value.   necessary.  










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NOT OK   OK  








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* Replace Pick-Up coil if   * Check control module for  

not to specification.   good ground connections.  










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OK  




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* If vehicle fails to run at this point, go to  
 the appropriate article in the ENGINE  
 PERFORMANCE section.  









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* Check wires from the battery/  * Replace ballast resistor 

ignition switch to the coil.   if the measured resistance 

Also check the coil primary   value is not within 

and secondary resistance.   specification. 










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STARTER 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 STARTER TROUBLE SHOOTING CHART









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CONDITION POSSIBLE CAUSE CORRECTION








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Starter Fails Dead battery or bad Check battery charge
to Operate connections between and all wires and
starter and battery connections to starter

connections for
tight and clean
connections
Ignition switch faulty Adjust or replace
or misadjusted ignition switch as
necessary









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Starter Cranks Battery weak or Charge or replace
Engine Slowly defective battery as necessary
Engine overheated See ENGINE COOLING
SYSTEM article
Engine oil too heavy Check that proper
viscosity oil
is used
Poor battery-to-starter Check that all
connections between
battery and starter are
clean and tight
Current draw too low or See Bench Tests in
too high STARTER article
Bent armature, loose pole See STARTER article
shoes screws or worn
bearings
Burned solenoid contacts Replace solenoid
Faulty starter Replace starter









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Starter Engages Engine timing too far See Ignition Timing in
Engine Only advanced TUNE-UP article
Momentarily
Overrunning clutch not Replace overrunning
engaging properly clutch. See STARTER
article
Broken starter clutch See STARTER article
Broken teeth on engine Replace flywheel and
flywheel check starter pinion
gear for damage
Weak drive assembly See STARTER article
thrust spring
Weak hold-in coil See Bench Tests in
STARTER article









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Starter Drive Defective point assembly See Testing in STARTER
Will Not Engage article
Poor point assembly ground See Testing in STARTER
article
Defective pull-in coil Replace starter
solenoid









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Starter Relay Dead battery Charge or replace