light MITSUBISHI 3000GT 1991 User Guide

FUEL
SYSTEM
CONTENTSM13AA- _
CRUISE CONTROL SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . .158SPECIFICATIONS. . . . . . . .._._....................................................155
CRUISE CONTROL SYSTEM*................................................185
SERVICE ADJUSTMENT PROCEDURES............................178
Cruise Control Cables Inspection and Adjustment........178Cruise Control SystemInspection....................................179individual Parts Inspection....................................................181
SPECIAL TOOLS........................................................................159
SPECIFICATIONS....................................................................158
General Specifications........................................................158Service Specifications........................................................158
TROUBLESHOOTING............................................................159
Check Chart............................................................................163Harness and Components Layout....................................176Preliminary Inspection........................................................159Self-diagnosis Checking........................................................172Troubleshooting Quick Reference Chart............................159
ENGINE CONTROL............................................155
ENGINE CONTROL................................................................157
SERVICE ADJUSTMENT PROCEDURES............................156
Accelerator Cable Inspection and Adjustment................156Accelerator Switch Inspection and Adjustment................156
Service Specifications........................................................
155
TROUBLESHOOTING............................................................
155
Accelerator Cable and Accelerator Pedal........................155
FUEL SYSTEM....................................................3
DETONATION SENSOR........................................................154
FUEL FILTER............................................................................
153
FUEL LINE AND VAPOR LINE................................................151
FUEL PUMP AND FUEL GAUGE UNIT ASSEMBLYAND OVERFILL LIMITER (TWO-WAY VALVE)................149
FUEL TANK.................................................................................146
GENERAL INFORMATION
....................................................
3
MPI System Diagram............................................................3
INJECTOR................................................................................141
ON-VEHICLE INSPECTION OF MPI COMPONENTS........36
Active Exhaust Control Unit ............................130Air Conditioner Switch and Power Relay............................82Air Flow Sensor....................................................................54Anti-lock Brake Signal ........................................133Barometric Pressure Sensor................................................60CONTINUED ON NEXT PAGE
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
(1)A Supplemental Restraint System (SRS), which uses a driver-side air bag, has been installed in the 3000GT.(2)The SRS includes the following components: impact sensors, SRS diagnosis unit: SRS warning light, air bagmodule, clock spring, interconnecting wiring. Other SRS-related components (that may have to be
removed/installed in connection with SRS service or maintenance) are indicated in the table of contents byan asterisk (*).
WARNING!(I)Improper service or maintenance of any component of the SRS, or any SRS-related component, can lead to
personal injury or death to service personnel (from inadvertent firing of the air bag) or to the driver (from
rendering the SRS inoperative).
(2) Service or maintenance of any SRS component or SRS-related component must be performed only at anauthorized MITSUBISHI dealer.
(3) MITSUBISHI dealer personnel must thoroughly review this manual, and especially its GROUP
528 -Supplemental Restraint System (SRS), before beginning any service or maintenance of any component of theSRS or any SRS-related component.

13-2
Boost Meter ........................................................128Components Inspection Procedure....................................40
Components Location........................................................36
Crank Angle Sensor
............................................................72Detonation Sensor................................................................84EGR Control Solenoid Valve
........................................121
EGR Temperature Sensor ............................92ElectricalLoad Switch........................................................86Engine and Transaxle Total Control Signal ............135Engine Control Unit Power Ground....................................44Engine Coolant Temperature Sensor................................62Fuel Pressure Control Valve ............................123Fuel Pressure Test................................................................138Fuel Pump ....................................................45Fuel Pump ............................................................48
Fuel Pump Operation Check................................................137Fuel Pump Relay No. 2........................................................53Fuel Pump Resistor............................................................53
Idle Position Switch............................................................68Idle Speed Control Servo (Stepper Motor Type)............1 IOIgnition Coil and Power Transistor....................................115Ignition Switch-ST and Inhibitor Switch ................76Ignition Switch-ST ................................................75Induction Control Valve Position Sensor
........................................................................90
Injectors........................................................101Injectors................................................................105Intake Air Temperature Sensor............................................57Muffler Mode Changeover Switch ....................88Oxygen Sensor ............................................
94
Oxygen Sensor ....................................................98
Power Steering Oil Pressure Switch................................80Power Supply and Ignition Switch-IG................................41
Purge Control Solenord Valve............................................1 19Release of Residual Pressure from High
Pressure Fuel Hose............................................................137Throttle Position Sensor....................................................65Top Dead Center Sensor....................................................70Variable Induction Control Servo (DC Motor)
........................................................................131Vehicle Speed Sensor........................................................78Waste Gate Control Solenoid Valve ................126
SERVICE ADJUSTMENT PROCEDURES............................31
Adjustment of Fixed SAS....................................................35Adjustment of Idle Position Switch and
Throttle Position Sensor (TPS)............................................33Basic Idle Speed Adjustment............................................31Throttle Body (Throttle Valve Area) Cleaning....................33
SPECIAL TOOLS........................................................................8
SPECIFICATIONS
....................................................................6
General Specifications........................................................6Sealant....................................................................................7Service Specifications........................................................7
THROlTLE BODY....................................................................143
TROUBLESHOOTING............................................................9
Check Chart Classified by Problem Symptoms................16Circuit Diagram....................................................................18Engine Warning Light (Malfunction Indicator Light)........11Explanation and Cautions about Harness Check............10Explanation of Troubleshooting Procedures....................9Fuel Tank and Fuel Line........................................................30
Problem Symptoms Table (For Your Information)............17Self-diagnosis........................................................................12)
I

FUEL SYSTEM - Troubleshooting13-11
L
L
Sensor side6FU1215
Malfunctionl
If the sensor impressed voltage is abnormal, check the wire
for an open circuit or short-circuit to ground and repair as
necessary. If the wire is normal, replace the engine control
unit and check again.l To check the voltage, use a digital voltmeter (or circuit
tester) as a rule.
[However, use an analog voltmeter for checking the power
transistor drive voltage.]ENGINE WARNING LIGHT (MALFUNCTION IN-
DICATOR LIGHT)
Among the self-diagnosis items, a malfunction indicator lightcomes on to notify the driver of the emission control items
when an irregurality is detected.
However, when an irregular signal returns to normal and theengine control unit judges that it has returned to normal, the
malfunction indicator light goes out.
Moreover, when the ignition switch is turned off, the light goes
out. Even if the ignition switch is turned on again, the light doesnot come on until the irregularity is detected.
Here, immediately after the ignition switch is turned on, the
malfunction indicator light is lit for 5 seconds to indicate that
the malfunction indicator light operates normally.
ITEMS INDICATED BY THE MALFUNCTION INDICATOR
LIGHT
Engine control unit
Oxygen sensor
Air flow sensor
Intake air temperature sensor
Throttle position sensor
Engine coolant temperature sensor
Crank angle sensor
Top dead center sensor
Barometric pressure sensor
Detonation sensor
Ignition timing adjustment signal
Injector
EGR system
Ignition coil, power transistor unit
Caution
The malfunction indicator light comes on when the line ofthe ignition timing adjustment terminal is shorted to
ground. Therefore, the light also comes on when the
ignition timing adjustment terminal is grounded to adjust
the ignition timing, but this does not show any abnormal-
ity.
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13-12FUEL SYSTEM - Troubleshooting
MALFUNCTION INDICATOR LIGHT INSPECTION
(1) Check that when the ignition switch is turned on, the lightilluminates for about 5 seconds and then goes out.
(2) If the light does not illuminate, check for open circuit in
dharness, blown fuse and blown bulb.
SELF-DIAGNOSIS
The engine control unit monitors the input/output signals (some
signals at all times and the others under specified conditions) ofthe engine control unit.
When it is noticed that an irregularity has continued for a
specified time or longer from when the irregular signal is
initially monitored, passing a certain number, the engine controlunit judges that an irregularity has occurred, memorizes the
malfunction code, and outputs the signal to the self-diagnosis
output terminal.
There are 21 diagnosis items, including the normal state, andthe diagnosis results can be read out with a voltmeter or
multi-use tester.Moreover, since memorization of the malfunction codes is
backed up directly by the battery, the diagnosis results are
memorized even if the ignition key is turned off. The malfunc-
tion codes will, however, be erased when the battery terminalor the engine control unit connector is disconnected.
The malfunction code can also be erased by turning on the
ignition switch and sending the malfunction code erase signalfrom the multi-use tester to the engine control unit.
CautionIf the sensor connector is disconnected with the ignition
_ _switch turned on, the malfunction code is memorized. Ind
this case, send the malfunction code erase signal from themulti-use tester to the engine control unit or disconnect
the battery terminal
(-) for 10 seconds or more, and the
diagnosis memory will be erased.
The 21 diagnosis items are provided as follows, and if plural
items are activated, they are all indicated sequentially from the
smallest code number.
CautionThe malfunction code for the ignition timing adjustment
signal is output when the line of the ignition timing
adjustment terminal is shorted to ground. Therefore, the
malfunction code is also output when the ignition timing
adjustment terminal is grounded to adjust the ignition
timing, but this does not show any abnormality.
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13-22FUEL SYSTEM - Troubleshooting
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13-28FUEL SYSTEM - Troubleshooting
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I

SERVICE ADJUSTMENT PROCEDURES
MlBFHSU
BASIC IDLE SPEED ADJUSTMENT
NOTE(1) The basic idle speed has been factory-adjusted with the
speed adjusting screw (SAS) and does not normally require
adjustment.(2) If the adjustment is required, first check that the ignition
plug, injector,
ISC servo, and compression pressure are
normal.
(1) Before starting the inspection and adjustment procedures,set the vehicle in the following conditions:
l
Engine coolant temperature: 80 to 95°C (176 to 205°F)l Lights, electric cooling fan, accessories: OFF
lTransaxle: Neutral (P range on vehicles with automatic
transaxle)l Steering wheel: Straightforward position
(2) When using the multi-use tester, connect it to the diagnosis
connector.
NOTEThe connection of the multi-use tester grounds the
self-
diagnosis/data transmission selector terminal.
(3) When not using the multi-use tester, proceed as follows:
@) Insert a paper clip into the l-pin blue connector as
shown in the illustration. FUEL SYSTEM
- Service Adjustment Procedurks13-31
i
@ Connect a primary-voltage-detecting tachometer to the
paper clip.
NOTEThe
tacho/neter should read l/3 of the actual engine
speed. This means that the actual engine speed is thetachometer reading multiplied by 3.
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FUEL SYSTEM - Service Adjustment Procedures13-33THROTTLE BODY
(THROTrLE VALVE AREA)
CLEANINGM13FICS
(1) Start the engine, warm it up until engine coolant tempera-ture rises to
80°C (176”F), and stop the engine.
(2) Disconnect the air intake hose at the throttle body side.
(3) Put a plug in the inlet of bypass passage in the throttle
body.
CautionNever allow cleaning agent to flow into the bypass
passage.(4) Spray cleaning agent from the intake port of the throttle
body to the valve and leave as it is for 5 minutes or so.
(5) Start the engine and race it several times. Then, run it idlefor approx. one minute.
NOTE
If the engine idle speed becomes unstable (and fails in theworst case) after plugging the bypass passage, run the
engine with the throttle valve slightly opened.
(6) If the deposit cannot be removed from the throttle valve,
repeat steps (4) and (5).
(7) Disconnect the plug from the inlet of the bypass passage.(8) Install the air ‘intake hose.
(9) Use a multi-use tester to erase the self-diagnosis code ordisconnect the battery ground cable for more than
IOseconds and then connect it again.
(lO)Adjust the basic idle speed (speed adjusting screw). (Referto
P.13-31.)
7FUO629
ADJUSTMENT OF IDLE POSITION SWITCH AND
THROTTLE POSITION SENSOR (TPS)M13FIFA(1) Disconnect the throttle position sensor connector.
(2) Using jumper wires, connect an ohmmeter across terminal
@ (idle position switch) and terminal @ (sensor ground) ofthe throttle position sensor.
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13-36FUEL SYSTEM - 0
n-vehicle Inspection of MPI Components
ON-VEHICLE INSPECTION OF MPI COMPONENTS
COMPONENTS LOCATION
EGR control solenoid valve
temperature sensor
Engine control unit
Engine coolant temperature sensor
Engine warning light
Fuel pressure control valve
Ignition coil (power transistor)
Ignition timing adjusting terminal
SSelf-diagnosis output terminal and self-diagnosis/Rdata transmission selector terminal
BTDC sensor and crank angle sensorD
PThrottle position sensor (with built-in idle switch)C
vVariable induction control servo (DC motor)J(with built-in induction control valve position
sensor)
MVehicle speed sensor (reed switch)F
QWaste gate solenoid valve U
NOTEThe “Name” column is in alphabetical order.TSB Revision

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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