1991 MITSUBISHI 3000GT cooling

FUEL SYSTEM - On-vehicle Inspection of MPI Components13-55
INSPECTIONUsing Multi-use Tester

Function
Data readingtern No. Data display
12Sensor airvolume(frequency)
Check conditionEngine stateStandard value
l Engine coolant tem-
700 rpm (Idle)25-50 Hzperature: 80 to 95°C
(176 to 205°F)2,000 rpm70-IOOHzl Lights and accessories:OFFRacingFrequency increasesl Transaxle: Neutralwith racing(P range for vehiclewith AIT)l Steering wheel: Neutral
NOTEWhen the vehicle is new [within initial operation of about 500 km (300 miles)], the air flow sensor output frequency maybe about 10% higher.

Function
Data listItem No. Data displayCheck conditionsEngine conditionsStandard value
34Reset signall Engine warm up700 rpm (Idle)ON
condition2,000 rpmOFF
L;
FunctionItem No. Data display
Data list37Volumetric
efficiencyCheck conditionEngine stateStandard valuel Engine coolant tem-700 rpm (Idle)20-35%
perature: 80 to 95°C
(176 to 205°F)
l Lights, electric cooling2,000 rpm15-30%
fan and accessory opera-tion: OFFl Transaxle: NeutralRacingFrequency increases
(P range for vehiclewith racingwith &T)
l Steering wheel: Neutral
Using Oscilloscope(1) Run the engine at idle speed.
(2) Connect the probe to the oscilloscope pick-up point as
shown in the circuit diagram, and check the waveform.
Regular waveform
03A0203
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13-102FUEL SYSTEM - On-vehicle Inspection of MPI Components
TROUBLESHOOTING HINTSHint 1: If the engine is hard to start when hot, check fuel pressure and check the injector for leaks.
Hint 2:If the injector does not when the engine that is hard to start is cranked, the following as well as the
Iinjector itself may be responsible.
(1) Faulty power supply circuit to the engine control unit, faulty ground circuit
\-J
-(2) Faulty control relay
Hint 3:(3) Faulty crank angle sensor, top dead center sensor
If there is any cylinder whose idle state remains unchanged when the fuel injection of injectors is cut
one after another during idling, make following checks about such cylinder.
(1) Injector and harness check
(2) Ignition plug and high tension cable check
(3) Compression pressure check
Hint 4: If the injector harness and individual part checks have resulted normal but the injector drive time is
out of specification, the following troubles are suspected.
(1)Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
(2) Loose EGR valve seating
(3) High engine resistance
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data displayCheck conditionCoolant temperatureStandard valueData reading 41
Drive time”’Engine: Cranking0°C (32”F)*zApprox. 17 ms
20°C (68°F)Approx. 46 ms
8O"C(176"F)Approx. 11 ms
Function
Data readingItem No.Data display
41Drive time*3l Engine coolant tem-perature: 80 to 95°C700 rpm (Idle)2.4-3.0 ms
(176 to 205°F)2,000 rpm2.0-2.6
msl Lamps, electric coolingfan, accessory units:When sharp racing isTo increaseAll OFF
madel Transaxle: Neutral
(P range for vehicle
with A/T)l Steering wheel: Neutral
Check conditionEngine stateStandard value ,
.---NOTE“I : The injector drive time refers to when the supply voltage is 11 V and the cranking speed is less than 250 rpm.*2: When coolant temperature is lower than 0°C (32°F). injection ismade by four-cylinders.---simultaneously.
“3: When the vehicle is new [within initial operation of about 500 km (300 miles)], the injector drive time may be about
10% longer.
Function
Actuator testItem No.
Drive content
Check conditionNormal state
01No. 1 injector shut offEngine: Idling afterIdle state to change
02No. 2 injector shut offwarm-up
(Shut off the injectorsfurther (becoming less
in sequence during afterstable or stalling)
03
No. 3 injector shut offengine warm-up, check
04No. 4 injector shut offthe idling condition)
05No. 5 injector shut off
06No. 6 injector shut off
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13-106FUEL SYSTEM - On-vehicle Inspection of MPI Components
INSPECTION
Using Multi-use Tester
FunctionItem No.Data displayCheck conditionCoolant temperatureStandard value‘L,,,J
DataDrive time*’0°C (32’F)*’readingiRea:bankiEngine: CrankingApprox. 53 ms
(FronT7bank)20°C (68°F)
Approx. 29 ms
80°C (176°F)Approx. 7 ms
FunctionItem No.
Data displayCheck conditionEngine stateStandard value
Datareading(Reaebank)Drive time*3l Engine coolant tem-700 rpm (Idle)1.9 - 2.5 ms
perature: 80 to 95°C
(Front7banki(176 to 205°F)2,000 rpm1.6 - 2.2 ms
l Lamps, electric coolingfan, accessory units:To increase
All OFFWhen sharp racing is
made
l Transaxle: Neutral(P range for vehicle
with A/T)
l Steering wheel: Neutral
NOTE“I : The injector drive time refers to when the supply voltage is 11 V and the cranking speed is less than 250 rpm.
“2: When coolant temperature is lower than 0°C (32°F). injection is made by four cylinders simultaneously.
“3: When the vehicle is new [within initial operation of about 500 km (300 miles)], the injector drive time may be about
10% longer.
Function
Actuator testItem No.
Drive contentCheck conditionNormal state
01No. 1 injector shut offEngine: Idling afterIdle state to changewarm-upfurther (becoming less
02No. 2 injector shut off(Shut off the injectorsstable or stalling)
03in sequence during afterNo. 3 injector shut offengine warm-up, checkthe idling condition)
04No. 4 injector shut off
05
No. 5 injector shut off
06
No. 6 injector shut off
\,iUsing
OscillqscopeI(1) Run the engine at idle speed.
(2) Connect the probe to the oscilloscope pick-up point as
shown in the circuit diagram, and check the waveform at
the drive side of each injector.~
-
LJ
4 AL A: InjectorNormal waveformdrive time03A0209
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FUEL SYSTEM - On-vehicle .lnspection of MPI Components13-111
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data display
Data reading 45
Stepper
1
motor steps
~
Check condition
l Engine coolant tem-
perature: 80 to 95°C
(176 to 205°F)
0 Lamps, electric cooling
fan, accessory units:
All OFFl Transaxle: Neutral(P range for vehiclewith AA>l Steering wheel: Neutrall Idle position switch: ON(compressor clutch
to be ON if air condi-
tioner switch is ON)l Engine: idling
Load stateStandard value
;;rnditioner switch:2 - 12 stp&conditioner switch:
25 - 65 stp
l $irNconditioner switch:15 - 63 stp0 Selector lever:Shift to D range
NOTEWhen the vehicle is new [within initial operation of about 500 km (300 miles)], the stepper motor steps may be about 30steps more than standard.
CautionWhen the selector lever is shifted to the “D”range, the brakes must be used to prevent the vehicle frommovingforward.
03A020
Using Oscilloscope(1) Connect the probe to each oscilloscope pick-up point as
shown in the circuit diagram.
(2) Start the engine.
(3) When the air conditioner switch is turned on, the idling
speed increases to operate the idle speed control. Check
the instantaneous waveform.
NOTEKeep in mind that the waveform can be observed only
when idle speed control is in operation.
1 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

14-2COOLING - SDecifications
SPECIFICATIONSGENERAL SPECIFICATIONSMMCA..
Items
Cooling method
Radiator
Type
Radiator fan motor
Type
Water pump
Type
Thermostat
Type
Identification markSpecifications
Water-cooled, pressurized, forced circulationwith electrical fan
Pressurized corrugated fin type
Direct current ferrite type
Centrifugal impeller type
Wax type with jiggle valve
76.5 (Stamped on flange)
dSERVICE SPECIFICATIONS
Items
Standard valueSpecifications
Range of coolant antifreeze concentration%30-60
Thermostat
Valve opening temperature of thermostat
“C (“F)
Full-opening temperature of thermostat“C (“F)
Opening pressure of cap high pressure valvekPa (psi)
Therm0 sensor (on radiator) operating temperature

OFF-t ON“C (“F)
ON -+ OFF“C (“F) condenser fan-Vehicles with air conditioner>
OFF-ON“C (“F)
ON + OFF“C (“F)
Limit
76.5 (170)
90
(I 94) or more
75-105(11-15)81-89
(178- 192)77(171)orless
91-99
(196-210.)
87 (189) or less
Opening pressure cap high pressure valve
kPa (psi)65 (9.2)LUBRICANT
MlQCD- -
ItemSpecified lubricantQuantity
Engine coolantlit. (qts.)High quality ethylene glycol8.0 (8.5).
antifreeze coolant
‘d
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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

14-4COOLING - Troubleshooting
CIRCUIT DIAGRAM
FUSIBL
RADIATOR
FAN ASSEMBLY
(RADIATOR
,
FAN MOTOR>r{
!&w
F
A-04X ,---LINK0
J
0A
j
IGNITION
J/B
lxI
ti
51.: ,A-07X
J1
>II
ticpLi6
m
R&
b3
,2L-R1
RADIATOR FAN ASSEMBLYL!a ml
T
X35-AC-NWOl-NY
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