1991 MITSUBISHI MONTERO air condition

CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







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

Incorrect injector pump Check pressure, see
housing pressure FUEL SYSTEMS









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







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









\









\









\









\









\






 







\
 OK   NOT OK 




\b 







\b








\









\









\
















\









\









\








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

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










\









\









\






\b
 correct resistance value. 
 








\









\









\




\b








\









\









\








 




 







\


OK   NOT OK  




\b 







\b 








\









\









\














\









\









\



 


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

correct resistance value.   necessary.  










\









\









\




\b









\









\









\


\b 








\









\









\








 








\




 

NOT OK   OK  








\b 



\b 








\









\









\














\









\









\



 


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

not to specification.   good ground connections.  










\









\









\




\b









\









\









\


\b 




 

OK  




\b 








\









\









\









\









\





 

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









\









\









\









\









\




\b 








\









\









\






\b








\









\









\









\









 







\

OK   NOT OK 




\b 







\b








\









\









\
















\









\









\








* 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. 










\









\









\






\b









\









\









\




\b

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









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







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

\









\









\









\









\









\









\







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









\









\









\









\









\









\









\







High Pitched Distance too small between
Whine After Engine starter pinion and flywheel
Fires With Key Flywheel runout contributes
released. Engine to the intermittent nature
Fires and Cranks
Normally









\









\









\









\









\









\









\







TUNE-UP TROUBLE SHOOTING - GAS ENGINE VEHICLES
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 SPARK PLUG TROUBLE SHOOTING CHARTS









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







Normal Spark Light Tan or Gray deposits No Action
Plug Condition
Electrode not burned or No Action
fouled
Gap tolerance not changed No Action









\









\









\









\









\









\









\







Cold Fouling or Overrich air/fuel mixture Adjust air/fuel
Carbon Deposits mixture, see ENGINE
PERFORMANCE section
Faulty choke Replace choke
assembly, see ENGINE
PERFORMANCE section
Clogged air filter Clean and/or replace
air filter
Incorrect idle speed or Reset idle speed and/
dirty carburetor or clean carburetor
Faulty ignition wires Replace ignition
wiring
Prolonged operation Shut engine off
at idle during long idle
Sticking valves or worn Check valve train
valve guide seals









\









\









\









\









\









\









\







Wet Fouling Worn rings and pistons Install new rings and
or Oil Deposits pistons

Excessive cylinder wear Rebore or replace
block
Excessive valve guide Worn or loose bearing
clearance









\









\









\









\









\









\









\







Gap Bridged Deposits in combustion Clean combustion
chamber becoming fused chamber of deposits
to electrode









\









\









\









\









\









\









\







Blistered Engine overheating Check cooling system
Electrode
Wrong type of fuel Replace with correct
fuel
Loose spark plugs Retighten spark plugs
Over-advanced ignition Reset ignition timing
timing see ENGINE PERFORMANCE









\









\









\









\









\









\









\







Pre-Ignition or Incorrect type of fuel Replace with correct
Melted Electrodes fuel
Incorrect ignition timing Reset ignition timing
see ENGINE PERFORMANCE
Burned valves Replace valves
Engine Overheating Check cooling system
Wrong type of spark plug, Replace with correct
too hot spark plug, see
ENGINE PERFORMANCE









\









\









\









\









\









\









\







Chipped Severe detonation Check for over-
Insulators advanced timing or
combustion
Improper gapping Re-gap spark plugs
procedure









\









\









\









\









\









\









\







Rust Colored Additives in unleaded Try different fuel
Deposits fuel brand









\









\









\









\









\









\









\







Water In Combus- Blown head gasket or Repair or replace
tion Chamber cracked head head or head gasket









\









\









\









\









\









\









\







NOTE: Before diagnosing an electronic ignition system, ensure that
all wiring is connected properly between distributor, wiring
connector and spark plugs. Ignition problem will show up
either as: Engine Will Not Start or Engine Runs Rough.
BASIC ELECTRONIC IGNITION TROUBLE SHOOTING CHARTS









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







Engine Won't Open circuit between Repair circuit
Start distributor and bulkhead
connector
Open circuit between Repair circuit
bulkhead connector and

ignition switch
Open circuit between Repair circuit
ignition switch and
starter solenoid









\









\









\









\









\









\









\







Engine Runs Fuel lines leaking or Tighten fitting,
Rough clogged remove restriction
Initial timing incorrect Reset ignition timing
see ENGINE PERFORMANCE
Centrifugal advance Repair distributor
malfunction advance
Defective spark plugs or Replace plugs or plug
wiring wiring









\









\









\









\









\









\









\







Component Failure Spark arc-over on cap, Replace cap, rotor or
rotor or coil or coil
Defective pick-up coil Replace pick-up coil
Defective ignition coil Replace ignition coil
Defective vacuum unit Replace vacuum unit
Defective control module Replace control module









\









\









\









\









\









\









\







BASIC ELECTRONIC IGNITION TROUBLE SHOOTING
CHARTS - USING OSCILLOSCOPE PATTERNS









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







Firing Voltage Retarded ignition timing Reset ignition
Lines are the Same, timing, see ENGINE
but Abnormally High PERFORMANCE section
Fuel mixture too lean Readjust carburetor,
see ENGINE PERFORMANCE
High resistance in coil Replace coil wire
wire
Corrosion in coil tower Clean and/or replace
terminal coil
Corrosion in distributor Clean and/or replace
coil terminal distributor cap









\









\









\









\









\









\









\







Firing Voltage Fuel mixture too rich Readjust carburetor,
Lines are the Same see ENGINE PERFORMANCE
but Abnormally Low
Breaks in coil wire causing Replace coil wire
arcing
Cracked coil tower causing Replace coil
arcing
Low coil output Replace coil
Low engine compression Determine cause and

repair








\









\









\









\









\









\









\







One or More, But Carburetor idle mixture Readjust carburetor,
Not All Firing not balanced see ENGINE PERFORMANCE
Voltage Lines are
Higher Than Others EGR valve stuck open Clean and/or replace
valve
High resistance in spark Replace spark plug
plug wires wires
Cracked or broken spark Replace spark plugs
plug insulator
Intake vacuum leak Repair leak
Defective spark plugs Replace spark plugs
Corroded spark plug Replace spark plugs
terminals









\









\









\









\









\









\









\







One or More, But Curb idle mixture not Readjust carburetor,
Not All Firing balanced see ENGINE PERFORMANCE
Voltage Lines Are
Lower Than Others Breaks in plug wires Replace plug wires
causing arcing
Cracked coil tower causing Replace coil
arcing
Low compression Determine cause and
repair
Defective spark plugs Replace spark plugs
Corroded spark plugs Replace spark plugs









\









\









\









\









\









\









\







Cylinders Not Cracked distributor cap Replace distributor
Firing terminals cap
Shorted spark plug wire Determine cause and
repair
Mechanical problem in Determine cause and
engine repair
Defective spark plugs Replace spark plugs
Spark plugs fouled Replace spark plugs









\









\









\









\









\









\









\







BASIC DRIVEABILITY PROBLEMS TROUBLE SHOOTING TABLE








\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\







Hard Starting Binding carburetor linkage Eliminate binding
Binding choke linkage Eliminate binding
Binding choke piston Eliminate binding
Restricted choke vacuum Check vacuum lines
for blockage

setting, see ENGINE
PERFORMANCE
Vacuum leak Eliminate vacuum leak
EGR valve malfunction Replace EGR valve









\









\









\









\









\









\









\







Poor Gasoline Cracked or broken vacuum Replace vacuum hoses
Mileage hoses
Vacuum leaks Repair vacuum leaks
Defective ignition wires Replace wires
Incorrect choke setting Readjust setting, see
ENGINE PERFORMANCE
Defective vacuum advance Replace vacuum advance
Defective spark plugs Replace spark plugs
Binding carburetor power Eliminate binding
piston
Dirt in carburetor jets Clean and/or replace
jets
Incorrect float adjustment Readjust float
setting, see FUEL
Defective power valve Replace power valve,
see ENGINE PERFORMANCE
Incorrect idle speed Readjust idle speed









\









\









\









\









\









\









\







Engine Stalls Improper float level Readjust float level
Leaking needle valve and Replace needle valve
seat and seat
Vacuum leaks Eliminate vacuum
leaks









\









\









\









\









\









\









\







VACUUM PUMP - DIESEL 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.
VACUUM PUMP (DIESEL) TROUBLE SHOOTING CHART









\









\









\









\









\









\









\







CONDITION POSSIBLE CAUSE CORRECTION








\









\









\









\









\









\









\