1991 MITSUBISHI 3000GT air condition

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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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

FUEL SYSTEM - On-vehicle Inspection of MPI Components13-119PURGE CONTROL SOLENOID VALVE
Q Harness side
connector
I
Control relay
@ Equipment side
connector connector
unit
OlAO324
Engine control unit connector
7FUO653OPERATION
lThe purge control solenoid valve is an ON-OFF type one which controls introduction of purge air from the
canister into the intake air plenum.
lThe battery power is supplied to the purge control solenoid valve through the control relay. When the
engine control unit turns ON the power transistor in the unit, current flows to the coil, introducing purge
air.
INSPECTION
Using Multi-use Tester
Function
Actuator testItem No.Drive content
Check conditionNormal state
08Solenoid valve from OFFIgnition switch: ONOperating sound is heard
to ONwhen driven
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13-122FUEL SYSTEM - On-vehicle Inspection of MPI Components
INSPECTIONUsing Multi-use Tester
Function
Actuator testItem No.
Drive content
Check condition
Normal state
10Change solenoid valve
from OFF to ON stateIgnition switch: ONOperating sound is heardwhen driven
HARNESS INSPECTION
1
@ Harness side
connector
Measure the power supply voltage.
Y01105*4Engine control unit
harness side connector
Control relay)
Repair the
-S harness.C@vJ-~)
d
Ls
ACTUATOR INSPECTIONRefer to GROUP 17
- Exhaust Gas Recirculation (EGR) System.
1 TSB Revision

13-124FUEL SYSTEM -On-vehicle Inspection of MPI Components
INSPECTIONUsing Multi-use tester
Function
Actuator testItem No.Drive content
Check conditionNormal state
09Turn solenoid valve fromIgnition switch: ONOFF to ONr%;reard when
HARNESS INSPECTION
@ Harness side
connector
Measure the power supply voltage.
l Connector: Disconnectedl Ignition switch: ON
Voltage
(V)2-* q
SVRepair thei* harness.(@m - Con-
trol relay)
7FUO527
Check for an open-circuit, or a short-circuit to ground, between the fuelpressure control solenoid valve andthe engine control unit.
lEngine controLunit connector:
Disconnected
lFuel pressure control valve con-nector: Disconnected
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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

13-134FUEL 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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FUEL SYSTEM - On-vehicle Inspection of Mql Components13439(10)Disconnect the vacuum hose from the fuel pressure
regulator, and then measure the fuel pressure while using a
finger to plug the end of the hose.
Standard value:
330
- 350 kPa (47 - 50 psi) at curb idle
295 - 315 kPa (43 - 45 psi) at curb idle(11
)Check to be sure that the fuel pressure during idling does
not decrease even after the engine is raced a few times.
(12)Use a finger to gently press the fuel return hose while
repeatedly racing the engine, and check to be sure that
there is fuel pressure in the return hose also.
NOTEThere will be no fuel pressure in the return hose if there is
insufficient fuel flow.
(13)lf the fuel pressure measured in steps (9) to (12) deviates
from the standard value range, check for the probable
cause by referring to the table below, and. then make the
appropriate repair.
IConditionProbable cause1 RemedyI
l Fuel pressure is too low.l Fuel pressure drops duringracing.l No fuel pressure in fuel returnhose.
Malfunction of the valve seat withinthe fuel pressure regulator, or fuel
leakage to return, side caused byReplace the fuel filter.
Replace the fuel pressure regulator.
Fuel pump low discharge pressure.Replace the fuel pump.
Fuel pressure is too high.
The valve within the fuel pressureregulator is sticking.Replace the fuel pressure regulator.
Clogging of the fuel return hose and/Clean or replace the hose
and/oror the pipe.pipe.
No change of the fuel pressureDamaged vacuum hose or nippleReplace the vacuum hose, or clean
when the vacuum hose is connected clogging.the nipple.
and when not connected.
Malfunction of the fuel pressure controlChecking the fuel pressure controlsystem system
1 TSB Revision