1991 MITSUBISHI 3000GT torque

13-14FUEL SYSTEM - Troubleshooting
routput
preference
order
7Diannosis item
Diagnosis code
IOutput signal patternNo.
36
39
121 Ignition timing
adjustment signalH
L
13Oxygen sensor ’(Turbo: Front bank)HRetainedl Harness and connectorl Oxygen sensorl Fuel pressurel Injectors (Replaceif defective)l Intake air leaks
Retained
l Harness and connectorl Injector coil resistance
5
I--
Injector12AOlO!
:nnnn
EGR
12A0105
14
41
Retainedl Harness and connectorl EGR thermo-sensorl EGRvalvel EGR control solenoidvalvel EGR valve controlvacuum
Retainedl Harness and connectorl Ignition coill Power transistor unit
16
lqnition coil,
12A0105
52power transistor unitINO. 2-5 cylinder)H
Lu Lnll
‘qnition coil.
12AO105
18Retainedl Harness and connectorl Ignition coill Power transistor unit
Retainedl Harness and connector(If harness and connector
are normal, replace only
transaxle control unit.)
Retainedl Harness and connector(If harness, connector
and induction control
valve are normal,
replace air intake
plenum assembly.)
--
Tower transistor unitH‘NO. 3-6 cylinder)
Ln
12A0105
A cable from trans-
axle control unit,Hfor transmission
of torque reductionLUUUUUI n
signal 12A0105
Induction control
valve position
61
62
sensorHLuutJvL
12A0105
Normal stateH-
NOTE-Replace the engine control unit if a malfunction code is output although the inspection reveals that there is no problem with the check
items.TSB Revision

13-64FUEL SYSTEM - 0
n-vehicle Inspection of MPI Components
7FUO670
Apply sealant
7FUO67’SENSOR INSPECTION
(1) Remove engine coolant temperature sensor from the
intake manifold.(2) With temperature sensing portion of engine coolant
temperature sensor immersed in hot water, check resis-
tance.
Temperature
“C (“F)Resistance (kCI)
0 (32)5.8
20 (68)2.4
40 (104)1.1
80 (176)0.3
(3) If the resistance deviates from the standard value greatly,
replace the sensor.
INSTALLATION
(1) Apply sealant to threaded portion.
Specified sealant: 3M NUT locking Part No. 4171 or
equivalent
(2) Install engine coolant temperature sensor and tighten it to
specified torque..Sensor tightening torque: 30 Nm (22
ft.lbs.)
(3) Fasten harness connectors securely.TSB Revision

FUEL SYSTEM - On-vehicle Inspection of MPI Components13-67
(sensor side, front view7FU048t7FUO67:
SENSOR INSPECTION(1) Disconnect the throttle position sensor connector
(2) Measure resistance between terminal @ (sensor ground)and terminal
@ (sensor power).
Standard value: 3.5
- 6.5 kR(3) Connect a pointer type ohmmeter between terminal
@(sensor ground) and terminal
@ (sensor output).
(4) Operate the throttle valve slowly from the idle position to
the full open position and check that the resistance changessmoothly in proportion with the throttle valve opening
angle.(5) If the resistance is out of specification, or fails to change
smoothly, replace the throttle position sensor.
Throttle position sensorinstallation torque: 2.0 Nm (1.5
ft.lbs.)For the idle position switch and throttle position sensor
adjusting procedure, refer to P. 13-33.
TSB Revision1

13-100FUEL SYSTEM - 0
n-vehicleInspection of MPI Components
SENSOR INSPECTION
(1) Disconnect the oxygen sensor (rear) connector and connect
the special tool, Test Harness, to the oxygen sensor (rear)
connector.
MD998464
7FUO339
e
MD9584647FUO340(2) Check that there is continuity [approx. 20
R at 20°C (68”F)Iacross terminals @ and @ of the oxygen sensor (rear)
connector.
(3) If there is no continuity, replace the oxygen sensor (rear).
(4) Warm up the engine until the engine coolant temperature
becomes 80°C (176°F) or higher.
(5) Using jumper wires, connect terminals @ (red clip of the
special tool) and @ (blue clip) of the oxygen sensor
connector to battery
0 and 0 terminals respectively.
Caution
Ensure that the jumper wires are connected correctly,
as wrong connections result in a broken oxygen sensor.
(6)Connect a digital voltmeter across terminals @ (black clip of
(7)the special tool) and @ (white clip).
Race the engine repeatedly and measure the output voltage
of the oxygen sensor (rear).
EngineOxygen sensor
output voltageRemarks
When engineis raced0.6-l.OVWhen the air-fuel mixturebecomes richer as a result
of repeated racing, the
oxygen sensor should outputa voltage of 0.6 - 1 .O V.
(8) If the measurements are not as specified, defective oxygen
sensor (rear) is suspected.
(9) Check the oxygen sensor (front) in the same way by
following steps
(I) through (8).
INSTALLATION
(1) For removal and installation of oxygen sensor, refer to
GROUP 15
- Exhaust Manifold.
(2) Tighten the oxygen sensor to specified torque.
TSB Revision

13-140FUEL SYSTEM - On-vehicle Inspection of MPI Components
(14)Stop the engine and check for a change of the value
indicated by the fuel pressure gauge. The condition is
normal if there is no decrease of the indicated value within~
two minutes.
,If there is a decrease of the indicated value, monitor the
:d ’speed of the decrease, and, referring to the table below,
determine the cause of the problem and make the
appropriate repair.
Condition
After the engine is stopped, thefuel pressure drops gradually.Probable cause
Injector leakage.
Leakage at the fuel pressure
regulator valve seat.Remedy
Replace the injector.
Replace the fuel pressure regulator.
There is a sudden sharp drop of
the fuel pressure immediately
after the engine is stopped.The check valve (within the fuelpump) is not closed.Replace the fuel pump.
(15)Remove all remaining pressure from inside the fuel pipe.(16)Disconnect the fuel pressure gauge and the special tool
from the delivery pipe.
CautionBecause there will be.a slight amount of remaining
pressure in the fuel pipe line, use rags to cover so thatfuel doesn’t splatter.
(17)Replace the O-ring at the end of the fuel high-pressure hose
with a new one.(I 8)After connecting the fuel high-pressure hose to the delivery
pipe, tighten the installation bolt at the specified torque.
dTightening torque: 5.0 Nm (3.6 ftlbs.)
(19)Check to be sure that there is no fuel leakage.@ Apply battery voltage to the terminal for activation of
the fuel pump so as to activate the fuel pump.@ With fuel pressure applied, check for leakage of the fuel
line.
TSB Revision

13-148FUEL SYSTEM - Fuel Tank
Canistide
Do3041Flare nut
Se&e side
0310430%
e:00817. INSTALLATION OF OVERFILL LIMITER (TWO-WAY
VALVE)Install so that the overfill limiter is facing in the direction
’,~
shown in the illustration.L.&l
12. CONNECTION OF HIGH PRESSURE FUEL HOSETemporarily tighten the flare nut by hand, and then tighten it
to the specified torque, being careful that the high pressure
fuel hose does not become twisted.
CautionWhen tightening flare nut, be careful not to bend or
twist line to prevent fuel pump from damage.
11. CONNECTION OF RETURN HOSEConnect the return hose to the pipe securely, up to the
stepped part, as shown in the illustration.
1. INSTALLATION OF FUEL GAUGE COVER
Before installing the fuel gauge cover, apply the specified
sealant to the rear floor pan.
Specified sealant: 3M ATD Part No. 8509 or equivalent
TSB Revision

13-150FUEL SYSTEMFuel Pump and Fuel Gauge Unit Assembly- and Overfill Limiter (Two-Way Valve)
Rubber hose
9Flare nut
Secure side
03Yo43Camst
ide
DO304INSPECTION
MlBUCAB
OVERFILL LIMITER (TWO-WAY VALVE)~
Connect a clean rubber hose to the overfill limiter and check for
operation.
‘d
Inspection procedureNormal conditionLightly blow from the inlet
(fuel tank) sideAir passes through after a
slight resistanceLightly blow from the outlet
(canister) sideAir passes through
SERVICE POINTS OF INSTALLATION
M13UDAC6. INSTALLATION OF FUEL PUMP AND FUEL GAUGE
UNIT ASSEMBLY
Align the three positioning projections of the packing with
the holes in the fuel pump and fuel gauge unit assembly.
5. 4. CONNECTION OF HIGH PRESSURE FUEL HOSE
Temporarily tighten the flare nut by hand, and then tighten it
to the specified torque, being careful that the high pressure
fuel hose does not become twisted.
CautionWhen tightening flare nut, be careful not to bend or
[J’twist line to prevent fuel pump from damage.\3. INSTALLATION OF OVERFILL LIMITER (TWO-WAY
VALVE)Install so that the overfill limiter is facing in the direction
shown in the illustration.
1. INSTALLATION OF FUEL GAUGE COVER
Before installing the fuel gauge cover, apply the specified
sealant to the rear floor pan.
Specified sealant: 3M ATD Part No. 8509 or equivalent
1 TSB RevisionIII

13-152FUEL SYSTEM- Fuel Line and Vapor Line
03FOO3
05FOO735 Nm7r; ft
Ihr-k” ._..I_.
@dFlare nut,xSERVICE POINTS OF REMOVAL
MlBKBAQ9. 13. REMOVAL OF EYE BOLT
Remove the eye bolt while holding the fuel filter nut
\securely.
Caution
Cover the hose connection with rags to prevent splash
of fuel that could be caused by some residual pressurein the fuel pipe line.
INSPECTION
MIBKCAJ
lCheck the hoses and pipes for cracks, bend, deformation
and clogging.
l Check the canister for clogging.
l Check the fuel filter for clogging and damage.
SERVICE POINTS OF INSTALLATION
MlSKDAU17.5. INSTALLATION OF FUEL VAPOR HOSE
/ 8. FUEL
RETURN HOSE
(1) If the fuel pipe has a stepped part, connect the fuel
hose to the pipe securely, up to the stepped part, as
shown in the illustration.
Iti(2) If the fuel pipe does not have a stepped part, connect
the fuel hose to the pipe securely, so that it is the
standard value.
Standard value: 25
- 30 mm (1.0 - 1.2 in.)
15. INSTALLATION OF HIGH PRESSURE FUEL HOSEApply engine oil to the hose union.
Insert the hose, being careful not to damage the O-ring, and
tighten securely.
CautionBecause there is high pressure applied between the
fuel pump and the injection mixer, be especially sure
that there is no fuel leakage in this area.
12. INSTALLATION OF FUEL FILTER(1) When installing the fuel filter, first temporarily install the
filter to the filter bracket; then insert the main pipe at
the connector part of the high pressure fuel pipe, and
manually screw in the main pipe’s flare nut.
(2) Holding the fuel filter nut, tighten the fuel main pipe’s
flare nut and eye bolt at the specified torque. Then
tighten the filter to the bracket.
TSB Revision1
‘d