1991 MITSUBISHI 3000GT air condition

id
LFUEL SYSTEM
- On-vehicle Inspection of MPI Components13-63
INSPECTIONUsing Multi-use Tester
LFunctionItem No. Data displayCheck condition
Coolant temperatureStandard valueData reading 21
SensorIgnition switch: ON or
At -20°C (-4°F)-20°C
temperatureengine operatingAt 0°C (32°F)0°C
HARNESS INSPECTION
Check for continuity of the groundcircuit.l Connector: Disconnected
Repair the---+ harness.

7FUO6682
Measure the power supply voltage.l Connector: Disconnected
@ Harness sidel Ignition switch: ON
7FUO669TSB Revision

13-66FUEL SYSTEM - 0n-vehicle Inspection of MPI Components
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data displayCheck conditionThrottle valveStandard value‘d
Data reading14SensorIgnition switch: left ONvoltagefor 15 seconds or moreAt idle position300-1.000 mV
Open slowly
Increases withvalve opening
Open widely4.500-5.500 mV
HARNESS INSPECTIONl Connector: Disconnected
l
lgnrtion switch: ON
l Connector: Disconnected
connector
I
Engine controlCheck for an open-circuit, or a short-
unit harnesscircuit to ground between the engine
side connectorcontrol unit and the throttle positionsensor.
Throttle position sensor connec-
tor: Disconnected
Engine control unit connector:
DisconnectedRepair theB-3 harness.
km-8)
-z =6FU1243
[ TSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components
L
L
IGNITION SWITCH-ST
lgnitlon switch (ST)
I
Enaine control unit connector
7FUO653
Engine control unit
1 FU0638
OPERATION
lThe ignition switch-ST inputs a high signal to the engine control unit while the engine is cranking. Theengine control unit provides fuel injection control, etc., at engine startup based on this signal.
lWhen the ignition switch is set to START, the battery voltage at cranking is applied through the ignitionswitch to the engine control unit, which detects that the engine is cranking.
INSPECTION
Using Multi-use Tester
FunctionItem No. Data displayCheck conditionEngineNormal indication
Data reading18Switch stateIgnition switch: ONstopOFF
CrankingON
HARNESS INSPECTION
1
L6FU1258
2
1
Engine control
side connector
IY-6FU1259
Measure the input voltage to theengine control unit.nlEngine control unit connector:Disconnectedl Ignition switch: START
Check for continuity of the groundcircuit.
lEngine control unit connector:Disconnected
Repair the
harness.
(m - Ground)
iTSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components13-77INSPECTION
Using Multi-use Tester
LIGNITION SWITCH-ST
FunctionItem No. Data displayCheck conditionEngineNormal rndrcation
Data reading18Switch stateIgnition switch: ON
stopOFF
CrankingONINHIBITOR SWITCH
FunctionItem No. Data displayCheck conditionSelect lever positionNormal indicationData reading 29
Shift
Ignition switch: ONP or NP or Nposition
D.2,L or RD.2.L or RHARNESS INSPECTION
@ Harness sideconnector
OlA0206
2
@ Harness srdeconnectorl
Engine control unit connector:
Connectedl
InhibItor switch connector: Dis-6a
L-J
cl3
connectedl Ignition switch: ON
Repair the
harness.Voltage
(VI@El - El)
OlA0206LII
Engine control
unit harness
side connector
Measure the power supply voltage of
the inhibitor switch.
-lEngine control unit connector:
Disconnectedl
lnhibrtor switch connector: Dis-
connectedl Ignition switch: START
Voltage
(V)
rLlltXK IlIt:Lpower supplycircuit.
Measure the inhibitor switch terminalinput voltage.
Measure the input voltage of enginecontrol unit.lEngine control unrt connector:DisconnectedlFer;it;r switch connector: Con-
1 TSB Revision

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.
TSB Revision

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)
TSB Revision