engine overheat MITSUBISHI 3000GT 1991 Service Manual

00-24GENERAL - Master Troubleshooting
MASTER TROUBLESHOOTING
MOOWWENGINE OVERHEATS
Symptom
Engine overheatsProbable cause
Cooling system
faulty
, incorrect ignition timing
Reference page
14-3
11-13
v’.ENGINE WILL NOT CRANK OR CRANKS SLOWLY
Symptom
Engine will not crankor cranks slowly
Probable cause
Starting system faulty
Reference page
16-15ENGINE WILL NOT START OR HARD TO START (CRANKS OK)
1 Symptom
Engine will not start or hard to
start (Cranks OK)Probable causeNo fuel supply to injector
injection system problems
Ignition system problems
Vacuum leaksl Purge control valve hosel Vacuum hosesl Intake manifoldl Air intake plenuml Throttle bodyl EGR valve
Reference page
-
-
16-25
17-3
Compression too low
11-15
d
1 TSB Revision1

GENERAL - Master Troubleshooting
ROUGH IDLE OR ENGINE STALLS
LProbable causeReference page or remedy
Symptom
Rough idle or engine stallsVacuum leaks
l Purge control valve hosel Vacuum hosesl Intake manifoldl Air intake plenuml Throttle bodyl EGR valve
Ignition system problems16-25
Idle speed set too lowCheck idle speed controlsystem
Idle mixture too lean or too rich-
Fuel injection system problems-
Exhaust gas recirculation (EGR) systemproblems17-11
Engine overheats
114-3
Compression too lowIll-15
ENGINE HESITATES OR POOR ACCELERATION
L
Reference pageSymptomProbable cause
Ignition system problem
Vacuum leaksl Purge control valve hosel Vacuum hosesl Intake manifoldl Air intake plenuml Throttle bodyl EGR valve
Air cleaner clogged
Fuel line clogged
Fuel injection system problem
Emission control system problem
l EGR system always on
Engine overheats
Compression too low11-13
Engine hesitates or poor
acceleration
17-3
15-9
-
17-11
14-3
TSB Revision

COOLINGCONTENTS
M14AA..
ENGINE COOLANT TEMPERATURE GAUGE
UNIT, ENGINE COOLANT TEMPERATURESENSOR AND ENGINE COOLANT
TEMPERATURE SWITCH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._.__15
RADIATOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
SERVICE ADJUSTMENT PROCEDURES . . . . . . . .7Cap Pressure Test
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._.......7Engine Coolant Concentration Test
. . . . . . . . . . . . . . . .‘7
L,Engine Coolant Leak Check
. . . . . . . . . . . . . . . . . . . . . . . . . . . .7Engine Coolant Replacement
. . . . . . . . . . . . . . . . . . . . . . . .7
SPECIFICATIONS. . . . . . . . . . . . .._.................................General Specifications
. ..___....___._...___.__............Lubricant
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._.................._........Sealant and Adhesive
. . . . . . . . . . . . . . . . .._...........Service Specifications
. . . . . . . . . . . . . . . . . . . . . . . . . .
THERMOSTAT. . . ..__......................_.._...................
TROUBLESHOOTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._...No Rise in Temperature
Overheat
WATER PUMP, WATER PIPE AND WATER
HOSE. . . . _......_........_ _.._ .._..... . . . . . . . . . . . ._. . . . . . . . . . . . . . . . .
2
2
2
3
2
11
3
13

COOLING - Specifications / Troubleshooting
SEALANT AND ADHESIVE14-3
MMCE- -
/
id
ItemsSpecified sealants and adhesive/
Engine coolant temperature gauge unit
Engine coolant temperature sensor (Engine control)
Engine coolant temperature sensor (Air conditioner)3M Nut Locking Part No. 4171
TROUBLESHOOTING
L
MllEAAL
Symptom
OverheatProbable cause
Insufficient engine coolant
Too high an anti-freeze concentration
Inoperative electric cooling fan
Faulty thermosensor
Faulty electrical motor
Faulty radiator fan relayRemedy
Replenish
Correct anti-freeze concentration
Replace
Damaged or blocked (insufficiently ventilated)
radiator finsCorrect
Water leaks
Damaged radiator core joint
Corroded or cracked hoses
(radiator hose, heater hose, etc.)
Faulty cap valve or setting of spring
Cracked thermostat housing
Loose water pump mounting bolt or leaking
gasket
Replace
Loose bolt or leaking gasket in water outlet
I
Correct or replacefitting
Loose bolt or leaking gasket in water inletfitting
Loose thermostat housing bolts or leakingfrom gasket
Retorque bolts or replace gasket
Faulty automatic transaxle oil cooler operation
Blocked or collapsed hose and pipeReplace
Loose hose and pipe connectionCorrect
Faulty thermostat operationReplace
Faulty water pump operationReplace
Water passage clogged with slime or rust depositClean
or foreign substance
No rise in temperature
Faulty thermostatReplace
( TSB Revision

17-14 EMISSION CONTROL -Exhaust Gas Recirculation (EGR) System / Catalytic Converter
6EM01871
6EM0181(4) Apply a vacuum and check for air-tightness when voltage
applied directly to the EGR control solenoid valve and when
the voltage is discontinued.
Battery voltageResult
When applied
When discontinued
Vacuum is maintained
Vacuum leaks
(5) Measure the resistance between the terminals of the
solenoid valve.
Standard value: 36
- 44 R [at 20°C (68”F)]
AIR-FUEL RATIO CONTROL (MPI) SYSTEMM17ICAJ
lTo inspect the air-fuel ratio control (MPI) system, refer to
GROUP1 3 - Service Adjustment Procedures.
lFor detailed information concerning the illumination pattern
of the malfunction-indicator light and other aspects of the
self-diagnosis function, refer to GROUP 13 -Self-diagnosis.
\.J
CATALYTIC CONVERTERMl7N& -
REMOVAL AND INSTALLATIONRefer to GROUP 15
- Exhaust Pipe, Main Muffler and Catalytic
Converter.
INSPECTIONMl7NCAA
Inspect for damage, cracking or deterioration. Replace if faulty.
Caution1. Operation of any type, including idling, should be
avoided if engine misfiring occurs. Under this conditionthe exhaust system will operate at abnormally high
temperature, which may cause damage to the catalystor underbody parts of the vehicle.
2.Alteration or deterioration of ignition or fuel system, or
any type of operating condition which results in enginemisfiring must be corrected to avoid overheating the
catalytic converters.
3.Proper maintenance and tune up according to manufac-turer’s specifications should be made to correct the
‘bi
conditions as soon as possible.TSB Revision