engine MITSUBISHI 3000GT 1991 Service Manual

FUEL SYSTEM - On-vehicle Inspection of MPI Components'13-127
INSPECTIONUsing Multi-use tester
LFunctionItem No.Drive contentCheck conditionNormal state
Actuator test12
Turn solenoid valve fromIgnition switch: ONOFF to ON
CliZli~,“eard when
HARNESS INSPECTION
Measure the power supply voltage.
l Connector: Disconnectedl Ignition switch: ON
trol relay)
7FUO525
Check for an open-circuit, or a short-circuit to ground, between the wastegate control solenoid valve and the
engine control unit.
lWaste gate control solenoid valveconnector: DisconnectedlEngine control unit connector:
DisconnectedRepair the
-+ harness.
(@m- ml)
7FUO526
ACTUATOR INSPECTIONRefer to GROUP 15.
1 TSB Revision

13-128FUEL SYSTEM - On-vehicle Inspection of MPI Components
BOOST METER <Turbo>
Ignition switch
(IG,)@ Equipment side
connector
Boost
meter
Engine
control
unit
111
i-F7FUO985
Engine control unit connector
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FUEL SYSTEM - On-vehicle Inspection of MPI Components13-129
i
HARNESS INSPECTION@ Harness side connector
*7FUO986Engine control unit
harness side
connect0r
1
Measure the power supply voltage.l Connector: Disconnected
l Ignition switch: ON
Voltage
(V)
svRepair the
harness.
(@I@-- Ini-tion coil9IG])
Check for an open-circuit or a short-circuit to ground, between the engine
control unit and the boost meter.
Boost meter connector: Discon-
nectedEngine control unit connector:Disconnected
ACTUATOR INSPECTIONRefer to GROUP 54.
1 TSB Revision

13-130FUEL SYSTEM - On-vehicle Inspection of MPI Components
ACTIVE EXHAUST CONTROL UNIT <Turbo>
Active
exhaust
control
unit
I
DCmotorforvalve drive
Al 12AA@ Equipment side
connector
Engine control unit connector
7FUO989
7FUO653
OPERATIONl Muffler noise is controlled by opening and closing the valve provided inside the main muffler.
l The valve is opened or closed by turning the DC motor in the normal or reverse direction.
lThe DC motor is driven in the normal or reverse direction by changing the direction of power flow by the
motor driving
IC in the active exhaust control unit.
lThe active exhaust control unit opens and closes the valve when it receives the signal produced by the
engine control unit.
HARNESS INSPECTION
0
FL
I’ JEngine control
unit harness
side connector
7FUO689I
Measure the input voltage of engine
ACTUATOR INSPECTIONRefer to GROUP 15.
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FUEL SYSTEM - On-vehicle lnwection of MPI ComDonents13-131
iVARIABLE INDUCTION CONTROL SERVO (DC MOTOR) <Non Turbo>Variable induction control servo
Y(DC motor)(with built-in induction/-control valve oosition sensor)-7Fllfl807Engine control unit
Close
connector
,\ IOpen@ Equipmentside1,,I2DC motorVariable
induction
control
servo
1 FU0646
Engine control unit connector
7FUO653
OPERATION
lAs the DC motor is driven clockwise or counterclockwise by the signal from the engine control unit, the
variable induction valve opens or closes.
lThe DC motor is driven clockwise or counterclockwise as the direction of current flow is changed by the
motor drive
IC in the engine control unit.
INSPECTIONUsing Multi-use tester
Function
Actuator testItem No.Drive content
Check conditionNormal state
11Drive the variable induc-Ignition switch: ONTurn the variable inductiontion control (MC) servovalve shaft (Variable induc-
(Open and close the
vari-tion valve: FULL CLOSEable induction valve)+ FULL OPEN
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13-132
IFUEL SYSTEM
- 0
n-vehicle Inspection of MPI Components
HARNESS INSPECTION
Engine control unitharness side connectorCheck for an open-circuit or a short-circuit to ground, between the enginecontrol unit and the variable inductioncontrol servo connector.l
Variable induction control servoconnector: DisconnectedlEngine control unit connector:Disconnected
t
Repair the
harness.
*A7FUO84
ACTUATOR INSPECTIONRefer to GROUP 15.
1 TSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components
ANTI-LOCK BRAKE SIGNAL <Turbo>
Engine control
unit connectorABS ECU@ ABS control unit
equipment side connector
A28
tABS HU
Engine
control
unit
114
/L6FU1542
7FUO653,
OPERATIONlThe anti-lock brake signal is input to the engine control unit from the anti-lock brake system
(ABS) control
unit as a signal to indicate whether or not the motor relay is activated. Based on this signal, the engine
control unit controls the idle-speed control servo to secure effective anti-lock braking.
lWhen the motor relay is activated, the ABS control unit turns ON the power transistor, short-circuiting the
terminal to ground. This causes the anti-lock brake signal to go from high to low.
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13-134FUEL SYSTEM - On-vehicle InsDection of MPI ComDonents
INSPECTIONUsing Multi-use Tester
FunctionItem No. Data displayCheck condition. Driving conditionStandard valueData reading 45
Stepper
Engine warmed up
Apply fairly sharp
To reach tempo-motor stepbraking at 50 km/h
rarily 70 to
(4th speed) to100 stepsstop vehicle
NOTESelect a place where a rear-end collision is unlikely.
HARNESS INSPECTION
side connector
Engine control umtharness side connecm
6FU1543
Check for an open-circuit or a short-circuit to ground, between the ABScontrol unit and the engine controlunit.l
ABS control unit connector: Dis-connectedlEngine control unit connector:
Disconnected7Repair the
harness.
(@m-ml)
I
I
I
I
IiI
I
~,
I\
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/
L/FUEL SYSTEM
- On-vehicle lnwection of MPI ComDonents13-135ENGINE AND TRANSAXLE TOTAL CONTROL SIGNAL <A/T>
Transaxle control unit
Engine control
unit
16FO292Engine
control
unit@ Transaxle control unit connector7FUO903Engine control unit connector
7FUO843
7FUO653
OPERATIONlThree communication lines are connected between the engine control unit and the transaxle control unit
to send and receive the engine and transaxle total control signal.
lIf the transistor inside the engine control unit changes from OFF to ON by the command of the engine
control unit, the terminal having a voltage of 5 V applied to it from the transaxle control unit is grounded in
the engine control unit.
This will change the terminal voltage of the transaxle control unit from HIGH to LOW.
If the transistor fitted inside the engine control unit changes from ON to OFF, the terminal, having applied
to it a voltage of 5 V from the transaxle control unit and grounded in the engine control unit, is released and
the terminal voltage of the transaxle control unit changes from LOW to HIGH.
In this way, the terminal voltage of the transaxle control unit is controlled by ON/OFF operation of the
transistor inside the engine control unit in order to send signal.
On the other hand, the transaxle control unit also controls the terminal voltage of the engine control unit
by the ON/OFF operation of the transistor fitted inside the transaxle control unit in order to send signal. In
this way, the engine and transaxle send control signal to each other.
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13-136FUEL SYSTEM - On-vehicle Inspection of MPI Components
HARNESS INSPECTION
’ IEngine control
unit harness
&;;;;;g;;gconnector
.j/ \%: c.
T
Check for an open-circuit, or a short-circuit to ground between the transax-’le control unit and the engine controlunit,
lTransaxle control unit connector:
Disconnected
lEngine control unit connector:
Disconnected
c----JOK
Repair the
harness.
C@pJ- 11161)
*6FU1543Engine control
unit harness
control
?ss side
6FU1543
-I3@ Transaxle control
unit harness sideEngine control
unit harness
side connector
6FU1543
Check for an open-circuit, or a short-circuit to ground between the transax-le control unit and the engine control-unit.
lTransaxle control unit connector:
Disconnected
lEngine control unit connector:
DisconnectedRepair the
harness.
@pJ-gj,
Check for an open-circuit, or a short-circuit to ground between the transax-
le control unit and the engine control
unit.
lTransaxle control unit connector:
Disconnected
lEngine control unit connector:
DisconnectedRepair the-+ harness.
@ml -FJ)
1 TSB Revision