display MITSUBISHI 3000GT 1991 User Guide

FUEL SYSTEM- On-vehicle Inspection of MPI Components13-81
INSPECTIONUsing Multi-use Tester
Function
Data readingItem No. Data displayCheck conditionSteering wheelNormal indication
27Switch stateEngine: IdlingSteering wheel neutralOFFposition (wheels
straight-ahead direction)
Steering wheel half turn
ON
Checking Oil Pressure
Steering wheelOil pump delivery pressure (ref. value)
Straight forward700 - 1,200 kPa (100 - 171 psi)
Turned1,500
- 2,000 kPa (213 - 284 psi)
HARNESS INSPECTION
i1
@ Harness side
connector
Measure the power supply voltage.
SENSOR INSPECTIONRefer to GROUP 37
- Service Adjustment Procedures.
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13-82FUEL SYSTEM - On-vehicle Inspection of MPI Components
AIR CONDITIONER SWITCH AND POWER RELAY
\
*I \\-- \
Air conditronerAir conditioner
control unitAir conditioner
compressor lock
controllerr
Engine control unit
Dual pressureswitch
M13YRAA2
b1IFF
Air conditioner
compressor
Engine control
unit connector
7FUO966
7FUO653
OPERATION
lThe air conditioner switch applies the battery voltage to the engine control unit when the air conditioner is
turned on.
lWhen the air conditioner ON signal is input, the engine control unit drives the idle speed control servo and
turns ON the power transistor. As a result, the air conditioner power relay coil is energized to turn on therelay switch, which activates the air compressor magnetic clutch.
TROUBLESHOOTING HINTS
If the air compressor magnet clutch is not activated when the air conditioner switch is turned on during idling,faulty air conditioner control system is suspected.
INSPECTION
Using Multi-use Tester
AIR CONDITIONER SWITCH
Function1 Item No. 1 Data display 1Check condition) Air conditioner switch 1 Normal indication IData reading 28
Switch stateEngine: Idling (airOFFOFFcompressor to be running
when air conditionerONONswitch is ON)\k”JTSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components
AIR CONDITIONER POWER RELAY
L
FunctionItem No. Data display
Data reading49Air condi-tioner relay
stateCheck conditionEngine: Idling after
warm-up
HARNESS INSPECTIONAir conditioner switch
Normal indication
OFFOFF (compressor
clutch non-activa-
tion)
ONON (compressorclutch activation)
’ I
unit harness
side connector
7FUO695
Measure the power supply voltage of
the air conditioner circuit.l
Air conditioner switch: ONlEngine control unit connector:
Disconnectedl Ignition switch: ON
l
Dual air conditioner switch: ONVoltage
(V)IM
ASTOP
Check the airconditioner
circuit.
AIR CONDITIONER INSPECTIONRefer to GROUP 55
- Service Adjustment Procedures.
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13-86FUEL SYSTEM - On-vehicle Inspection of MPI Components
ELECTRICAL LOAD SWITCH16FO29;
Tail-lightrelayDefog.wrelaystoplight
t;1
switch
ti* . .
Engine control unit connector
Engine
control
unit7FUO653
7FUO688OPERATION
lThe electrical load switch inputs ON/OFF state of the switch of equipment that consumes much powerduring idling, namely, equipment with a large electrical load, to the engine control unit. Based on this
signal, the engine control unit controls the idle-speed control servo.
l
When the switch of equipment with a large electrical load is turned ON, the battery voltage is applied tothe engine control unit to indicate that the equipment switch is turned ON.,
LJINSPECTION
Using Multi-use Tester
Function
Data reading
I
tem No. Data display
-I-
33Switchstate
Check condition
Equipment stateNormal display
$;ration of equipment:L$ing;Atch only:OFF + ON-3
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13-88FUEL SYSTEM - On-vehicle Inspection of MPI Components
MUFFLER MODE CHANGEOVER SWITCH
Engine control unit
r
@ Equipment sideconnector3
-Muffler
modeOFF changeover
ONswitch
2
r
7FU1053
OPERATIONlIf the operator turns the muffler mode changeover switch to ON or OFF position, this is converted to
high/low voltage to be sent to the engine control unit. Receiving this signal, the engine control unit
performs the dual mode (TOUR/SPORT mode) muffler control.
lThe output terminal of the muffler mode changeover switch has battery voltage applied to it from the
engine control unit through the resistor inside the unit. Place the muffler-mode changeover switch to the ‘LJj
ON posrtton, and the muffler mode changeover switch circuit will be closed to short the voltage applied
output terminal to the ground.. Accordingly, the output voltage of the muffler mode changeover switchchanges from high to low.
INSPECTION
Using Multi-use Tester
FunctionItem No. Data displayCheck conditionMuffler mode changeover Normal displayswitch condition
Data list35Switch
conditionIgnition switch: ONTurn to TOUR mode
Turn to SPORT modeON
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FUEL SYSTEM- On-vehicle Inspection of MPI Components13-93INSPECTION
Using Multi-Use Tester
FunctionItem No. Data displayCheck conditionEngine stateStandard valueData reading 43
SensorEngine: Warmed up700 rpm (Idle)100°C (212°F) or less
temperatureEngine is maintained in-
a constant state for3,500 rpm120°C (248°F) or more
2 minutes or moreHARNESS INSPECTION
connector
2-..-I
@ Harness side
connector
m2 1
4
1
Measure the power supply voltage.l Connector: Disconnected
l Ignition switch: ON
Voltage
(V)4.3
- 4.7Repair the
harness.
(@I@ - q I
Check for continuity of the groundcircuit.
l Connector: Disconnected
I
Repair the
harness.@@J-m,
SENSOR INSPECTION
Refer to GROUP 17 - Exhaust Gas Recirculation (EGR) System.TSB Revision

FUEL SYSTEM - 0
n-vehicle Inspection of MPI Components13-95
TROUBLESHOOTING HINTSHint 1: Poor cleaning of exhaust gas will result if the oxygen sensor fails.
Hint 2:If the oxygen sensor check has resulted normal but the sensor output voltage is out of specification,
troubles of parts related to air fuel ratio control system are suspected.
[Examples]
(1) Faulty injector
(2) Air leaking into the intake manifold through gasket gap, etc.
(3) Faulty air flow sensor, intake air temperature sensor, barometric pressure sensor,’ engine
Data readingcoolant temperature sensor
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data displayCheck conditionEngine stateStandard value
11SensorvoltaceEngine: Warm-upWhen sudden200 mV or lower
(make the mixture leandeceleration from
L
by engine speed reduc-4,000 rpm
tion, and rich by racing)
When engine is600-1,000 mV
suddenly raced
Engine: Warm-up700 rpm (Idle)
400 mV or lower
(using the oxygen sensorsignal, check the air/2,000 rpm,,,5-‘$-$-;3
fuel mixture ratio, and
also check the condition
of control by the engine
control unit)
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FUEL SYSTEM - 0
n-vehicleInspection of MPI Components
OXYGEN SENSOR
M13YHAA2I
2
2-J
_ Fr;;syn m-wr
li \\\Oxygen sensor
I7FU1004Theoretical A/F@Oxygen sensor
(rear)Oxygen sensor
Equipment side(front)@,ConnectorEquipment side:connectorf-l -1
Lonrrol relay--Control relay
Engine control unit 56
141516PJFEC1007Engine control unit connector
7FUO453
I
I7FU1016@ Harness side@ Harness side
Connector
connector
OPERATION
TROUBLESHOOTINGRefer to “OXYGEN SENSOR”
(P.13-94).
INSPECTIONUsing Multi-use Tester
Function
Data readingItem No.
i rL&
(f fzt,
,
1
Data display
Sensordetectionvoltage
Check condition
Engine: Warm-up(Make the mixture lean by enginespeed reduction, and rich byracing)Engine condition
Standard value
When sudden200 mV or
decelerationlowerfrom 4,000 rpm
When engine is
600-1.000 mV
suddenly raced
./
Engine: Warm-up
(Using the oxygen sensor signal,
check the air/fuel mixture ratio,and also check the condition ofcontrol by the engine control unit)
700 rpm(Idling)2,000 rpm400 mV orlower
6()(f--(~jbaono9~;
‘d
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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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