1997 MITSUBISHI TRITON ignition

GENERAL ± Supplemental Restraint System (SRS)00-31
Harness connector
(No. of terminals,
colour)SDU
terminal
No.Destination of harnessCorrective action
2 pins, red1, 2Body wiring harness
Clock springReplace clock spring
±3, 4±±
±5, 6±±
14 pins, red7, 8±±
9Body wiring harness
Diagnosis connectorCorrect or replace each
wiring harness
10Body wiring harness
Front wiring harness

Ignition switch (ST)
wiring harness
11Body wiring harness
Junction block (fuse No. 11)
12Body wiring harness
Junction block (fuse No. 10)
13Body wiring harness
Combination meter (SRS
warning lamp)
14±±
15Body wiring harness
Front wiring harness

Front impact sensor (+) (R.H.)Sensor cable* installa-
tion procedures
(Refer to GROUP 52B )16Body wiring harness
Front wiring harness

Front impact sensor (+) (L.H.)(Refer to GROUP 52B.)
17Body wiring harness
Front wiring harness

Front impact sensor (±) (L.H.)
18Body wiring harness
Front wiring harness

Front impact sensor (±) (R.H.)
19, 20Body wiring harness
EarthCorrect or replace each
wiring harness
NOTE
The sensor cable marked with * is available as service part.
7. SRS components should not be subjected to heat over 93
C, so remove the SRS-diagnosis unit,
air bag module, clock spring and front impact sensors before drying or braking the vehicle after painting.
8. Whenever you finish servicing the SRS, check warning lamp operation to make sure that the system
functions properly. (Refer to GROUP 52B ± SRS Maintenance.)
9. Make certain that the ignition switch is OFF when the MUT-II is connected or disconnected.
10. If you have any questions about the SRS, please contact your local distributor.
NOTE
SERIOUS INJURY CAN RESULT FROM UNINTENDED AIR BAG DEPLOYMENT, SO USE ONLY
THE PROCEDURES AND EQUIPMENT SPECIFIED IN THIS MANUAL.

11A-2
ENGINE <4G6>
CONTENTS11109000399
GENERAL INFORMATION 3. . . . . . . . . . . . . . . . . .
SERVICE SPECIFICATIONS 3. . . . . . . . . . . . . . . . .
SEALANT 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPECIAL TOOLS 5. . . . . . . . . . . . . . . . . . . . . . . . . . .
ON-VEHICLE SERVICE 7. . . . . . . . . . . . . . . . . . . . .
Drive Belt Tension Check and Adjustment 7. . . . .
Ignition Timing Check and Adjustment 10. . . . . . .
Idle Speed Check 11. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Mixture Check 11. . . . . . . . . . . . . . . . . . . . . . . . . . .
Compression Pressure Check 12. . . . . . . . . . . . . . . .
Manifold Vacuum Check 13. . . . . . . . . . . . . . . . . . . . . Lash Adjuster Check 14. . . . . . . . . . . . . . . . . . . . . . . .
CAMSHAFT OIL SEAL 16. . . . . . . . . . . . . . . . . . . .
OIL PAN, OIL SCREEN 19. . . . . . . . . . . . . . . . . . . .
CYLINDER HEAD GASKET 21. . . . . . . . . . . . . . . .
TIMING BELT, TIMING BELT B 26. . . . . . . . . . . .
CRANKSHAFT FRONT OIL SEAL 32. . . . . . . . . .
CRANKSHAFT REAR OIL SEAL 35. . . . . . . . . . .
ENGINE ASSEMBLY 37. . . . . . . . . . . . . . . . . . . . . .

ENGINE <4G6> ± Service Specifications11A-4
ItemsLimit Standard value
A/C compres-
sor drive belt
Tension NWhen checked355 ± 445±
sor drive belt
tensionWhen a used belt is installed355 ± 445±
When a new belt is installed530 ± 620±
Deflection
(Reference
When checked6.0 ± 7.0±
(Reference
value) mmWhen a used belt is installed6.0 ± 7.0±
When a new belt is installed4.5 ± 5.5±
Basic ignition timing5
BTDC+2
±
Idle speed r/min750+100±
CO contents %0.5 or less±
HC contents ppm100 or less±
Compression pressure
(250±400 r/min) kPa
4G631,270min. 960
(250±400 r/min) kPa
4G641,320min. 1,000
Compression pressure difference of all cylinder kPa±max. 100
Intake manifold vacuum kPamin. 60±
Cylinder head bolt shank length mm±99.4
Auto-tensioner push rod movement mmWithin 1.0±
Timing belt tension torque Nm (Reference value)3.5±
Auto tensioner rod protrusion mm2.5 ± 3.0±

ENGINE <4G6> ± On-vehicle Service11A-11
16. Attach a sealing tape to the fixing bolt and nut only for
vehicles for Switzerland.
NOTE
Sealing tape is attached to all new vehicles.
IDLE SPEED CHECK11100190330
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Check the basic ignition timing. Adjust if necessary.
Standard value: 5 BTDC+2
3. After turning the ignition switch to OFF, connect the MUT-II
to the diagnosis connector.
4. Start the engine and run it at idle.
5. Run the engine at idle for 2 minutes.
6. Check the idle speed.
Curb idle speed: 750+100 r/min
NOTE
The idle speed is controlled automatically by the idle speed
control (ISC) system.
7. If the idle speed is outside the standard value, inspect
the MPI components by referring to GROUP 13A ±
Troubleshooting.
IDLE MIXTURE CHECK11100210265
1. Before inspection, set the vehicle to the pre-inspection
condition.
2. Check that the basic ignition timing is within the standard
value.
Standard value: 5 BTDC+2
3. Turn the ignition switch to OFF and connect the MUT-II
to the diagnosis connector.
4. Start the engine and run it at 2,500 r/min for 2 minutes.
5. Set the CO, HC tester.
6. Check the CO contents and the HC contents at idle.
Standard value:
CO contents: 0.5% or less
HC contents: 100 ppm or less
7. If there is a deviation from the standard value, check
the following items:

Diagnosis output

Closed-loop control (When the closed-loop control
is normal, the output signal of the oxygen sensor
changes between 0 ± 400 mV and 600 ± 1,000 mV
at idle.)

MPI ± General Information13A-3
MULTIPOINT FUEL INJECTION (MPI)13100010265
GENERAL INFORMATION
The Multipoint Fuel Injection System consists
of sensors which detect the engine conditions,
the engine-ECU which controls the system
based on signals from these sensors, and
actuators which operate under the control of
the engine-ECU. The engine-ECU carries outactivities such as fuel injection control, idle
speed control and ignition timing control. In
addition, the engine-ECU is equipped with
several diagnosis modes which simplify
troubleshooting when a problem develops.
FUEL INJECTION CONTROL
The injector drive times and injector timing are
controlled so that the optimum air/fuel mixture
is supplied to the engine to correspond to the
continually-changing engine operation condi-
tions.
A single injector is mounted at the intake port
of each cylinder. Fuel is sent under pressure
from the fuel tank by the fuel pump, with the
pressure being regulated by the fuel pressure
regulator. The fuel thus regulated is distributed
to each of the injectors.
Fuel injection is normally carried out once for
each 2-cylinder group for every two rotationsof the crankshaft. This is called group fuel
injection. The engine-ECU provides a richer
air/fuel mixture by carrying out ªopen-loopº
control when the engine is cold or operating
under high load conditions in order to maintain
engine performance. In addition, when the
engine is warm or operating under normal
conditions, the engine-ECU controls the air/fuel
mixture by using the oxygen sensor signal to
carry out ªclosed-loopº control in order to obtain
the theoretical air/fuel mixture ratio that
provides the maximum cleaning performance
from the three way catalyst.
IDLE AIR CONTROL
The idle speed is kept at the optimum speed
by controlling the amount of air that bypasses
the throttle valve in accordance with changes
in idling conditions and engine load during
idling. The engine-ECU drives the idle speed
control (ISC) motor to keep the engine running
at the pre-set idle target speed in accordance
with the engine coolant temperature and airconditioner load. In addition, when the air
conditioner switch is turned off and on while
the engine is idling, the ISC motor operates
to adjust the throttle valve bypass air amount
in accordance with the engine load conditions
in order to avoid fluctuations in the engine
speed.
IGNITION TIMING CONTROL
The power transistor located in the ignition
primary circuit turns ON and OFF to control
the primary current flow to the ignition coil. This
controls the ignition timing in order to provide
the optimum ignition timing with respect to theengine operating conditions. The ignition timing
is determined by the engine-ECU from the
engine speed, intake air volume, engine coolant
temperature and atmospheric pressure.
SELF-DIAGNOSIS FUNCTION

When an abnormality is detected in one
of the sensors or actuators related to
emission control, the engine warning lamp
(check engine lamp) illuminates as a
warning to the driver.

When an abnormality is detected in one
of the sensors or actuators, a diagnosiscode corresponding to the abnormality is
output.

The RAM data inside the ENGINE-ECU
that is related to the sensors and actuators
can be read by means of the MUT-II. In
addition, the actuators can be force-driven
under certain circumstances.

MPI ± Troubleshooting13A-9
Engine warning lamp inspection items
Engine-ECU
Oxygen sensor
Air flow sensor
Intake air temperature sensor
Throttle position sensor
Engine coolant temperature sensor
Crank angle sensor
Top dead centre sensor
Barometric pressure sensor
Ignition timing adjustment signal
Injector
Immobilizer system
Caution
Engine warning lamp will come on even when terminal
for ignition timing adjustment is short-circuited.
Therefore, it is not abnormal that the lamp comes
on even when terminal for ignition timing adjustment
is short-circuited at the time of ignition timing
adjustment.
METHOD OF READING AND ERASING DIAGNOSIS
CODES
Refer to GROUP 00 ± How to Use Troubleshooting/Inspection
Service Points.
INSPECTION USING MUT-II DATA LIST AND
ACTUATOR TESTING
1. Carry out inspection by means of the data list and the
actuator test function.
If there is an abnormality, check and repair the chassis
harnesses and components.
2. After repairing, re-check using the MUT-II and check that
the abnormal input and output have returned to normal
as a result of the repairs.
3. Erase the diagnosis code memory.
4. Remove the MUT-II.
5. Start the engine again and carry out a road test to confirm
that the problem has disappeared.

MPI ± Troubleshooting13A-10
FAIL-SAFE FUNCTION REFERENCE TABLE13100910190
When the main sensor malfunctions are detected by the diagnosis function, the vehicle is controlled
by means of the pre-set control logic to maintain safe conditions for driving.
Malfunctioning itemControl contents during malfunction
Air flow sensor1. Uses the throttle position sensor signal and engine speed signal (crank angle sensor
signal) to take reading of the basic injector drive time and basic ignition timing from
the pre-set mapping.
2. Fixes the ISC servo in the appointed position so idle control is not performed.
Intake air temperature
sensorControls as if the intake air temperature is 25
C.
Throttle position
sensor (TPS)No increase in fuel injection amount during acceleration due to the throttle position sensor
signal.
Engine coolant
temperature sensorControls as if the engine coolant temperature is 80
C.
Top dead centre
sensorInjects fuel to all cylinders simultaneously.
(However, after the ignition switch is turned to ON, the No. 1 cylinder top dead centre is not
detected at all.)
Barometric pressure
sensorControls as if the barometric pressure is 101 kPa.
Oxygen sensorAir/fuel ratio feedback control (closed loop control) is not performed.
INSPECTION CHART FOR DIAGNOSIS CODES13100870214
Code No.Diagnosis itemReference page
11Oxygen sensor system13A-11
12Air flow sensor system13A-12
13Intake air temperature sensor system13A-12
14Throttle position sensor system13A-13
21Engine coolant temperature sensor system13A-14
22Crank angle sensor system13A-15
23Top dead centre sensor system13A-16
24Vehicle speed sensor system13A-17
25Barometric pressure sensor system13A-18
36*Ignition timing adjustment signal system13A-19
41Injector system13A-19
54Immobilizer system13A-20
NOTE
*: Malfunction code No. 36 is not memorized.

MPI ± Troubleshooting13A-11
INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No. 11 Oxygen sensor systemProbable cause
Range of Check

3 minutes have passed after engine was started.

Engine coolant temperature is approx. 80C or more.

Intake air temperature is 20 ± 50C.

Engine speed is approx. 2,000 ± 3,000 r/min

Vehicle is moving at constant speed on a flat, level road surface
Set conditions

The oxygen sensor output voltage is around 0.6 V for 30 seconds (does not cross
0.6 V for 30 seconds).

When the range of check operations given above which accompany starting of
the engine are carried out four time in succession, a problem is detected after
each operation.
Malfunction of the oxygen sensor

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
Check the oxygen sensor. (Refer to P.13A-88.)NG
Replace
OK
Measure at the oxygen sensor connector B-03.

Disconnect the connector, and measure at the
harness side.
1. Voltage between 1 and earth (Ignition switch: ON)
OK:System voltage
2. Continuity between 2 and earth
OK:Continuity
OK1. NG
Check the harness wire between the
oxygen sensor and the control relay
connector, and repair if necessary.
2. NG
Check the following connector.
C-51, C-60NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between the
engine-ECU and the oxygen sensor
connector.NG
Repair
OK
Replace the engine-ECU.
Measure at the engine-ECU connector C-50.

Disconnect the connector, and measure at the
harness side.

Voltage between 35 and earth (Ignition switch: ON)
OK:System voltage
NGCheck the following connector.
B-03, C-60NG
Repair
OK
Check the following connectors.
B-03, C-50NG
RepairCheck trouble symptom.OK
OKNGCheck the harness wire between the
engine-ECU and the oxygen sensor
connector, and repair if necessary.
Check trouble symptom.
NG
Check the harness wire between the engine-ECU and
the oxygen sensor connector.NG
Repair
OK
Replace the engine-ECU.