1997 MITSUBISHI TRITON fuel

MPI ± Troubleshooting13A-53
INSPECTION PROCEDURE 42
Check the engine-ECU power supply and earth circuit.
OK
Check trouble symptom.
OK
Check the harness wire
between engine-ECU and
ignition switch connector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
4. NG
Check the harness wire between engine-ECU and earth, and repair
if necessary.
5. NG
OK
Check the following
connectors.
C-49, C-50, C-51NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
Check the following connectors.
A-56X, C-19, C-81, C-87NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between engine-ECU and battery, and
repair if necessary.
NG
Check the harness wire between the engine-ECU and control relay,
and repair if necessary.
OK
Check trouble symptom.
2, 3. NG
Check the following
connector. C-53NG
Repair
Measure the engine-ECU connectors, C-49, C-50, C-51.

Disconnect the connector and measure at the harness side
1. Voltage between 62 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 38 and earth
OK:System voltage
3. Voltage between 12, 25 and earth (Ignition switch: ON)
OK:System voltage (when the terminal 38 is earthed)
4. Continuity between 13, 26 and earth
OK:Continuity
5. Voltage between 60 and earth
OK:System voltage1. NGCheck the following
connector. C-88NG
Repair
INSPECTION PROCEDURE 43
Check fuel pump circuit.
Measure at the fuel pump connector F-17.

Disconnect the connector and measure at the harness side.

Continuity between 2 and earth
OK:ContinuityNGCheck the following connectors.
D-02, F-17NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between fuel pump and earth, and repair
if necessary.
OK
Check the following connectors. C-19, D-02, F-17NG
Repair OKCheck trouble symptom.
NG
Check the harness wire between terminal for fuel pump drive and
fuel pump connector.NG
Repair
OK
Replace the fuel pump.

MPI ± Troubleshooting13A-54
INSPECTION PROCEDURE 44
Check the fuel pump drive control circuit.
Measure at the fuel pump relay connector C-54.

Disconnect the connector and measure at the harness side.

Voltage between 4 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between fuel pump relay
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
OK
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.


Voltage between 8 and earth (Ignition switch: ON)
OK:System voltage


Voltage between 22 and earth (Ignition switch: ON)
OK:System voltageNG
Check the following
connector. C-54NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and fuel pump relay
connector, and repair if necessary.
OK
Check the following connector. C-49NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 45
Check air flow sensor (AFS) control circuit.
Measure at the air flow sensor connector A-77.

Disconnect the connector and measure at the harness side.
1. Voltage between 4 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8 ± 5.2 V
3. Continuity between 5 and earth
OK:Continuity1. NGCheck the harness wire between the air flow sensor and control
relay connector, and repair if necessary.
2, 3. NGCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and air flow sensor con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector. A-77NG
Repair
OK
Check trouble symptom.
NG
Replace the air flow sensor.

MPI ± Troubleshooting13A-57
DATA LIST REFERENCE TABLE13100890180
Caution
When shifting the select lever to D range, the brakes should be applied so that the vehicle does
not move forward.
NOTE
*1. In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.
*
2. The idle position switch normally turns off when the voltage of the throttle position sensor is 50 ±
100 mV higher than the voltage at the idle position. If the idle position switch turns back on after
the throttle position sensor voltage has been by 100 mV and the throttle valve has been opened,
the idle position switch and the throttle position sensor need to be adjusted.
*3. The injector drive time represents the time when the cranking speed is at 250 r/min or below when
the power supply voltage is 11 V.
*4. In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%
longer than the standard time.
*5. In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes
30 steps greater than the standard value.
Item
No.Inspection
itemInspection contentsNormal conditionInspection
procedure
No.Reference
page
11Oxygen
sensorEngine:After having
warmed up
Air/fuel mixture is
made leaner when de-
When at 4,000 r/min,
engine is suddenly
decelerated200 mV or lessCode No.
1113A-11
made leaner when de-
celerating, and is made
richer when racing.
When engine is
suddenly raced600 ± 1,000 mV
Engine:After having
warmed up
The oxygen sensor
signal is used to check
the air/fuel mixture
ratio and control
Engine is idling400 mV or less
(Changes)
600 ± 1,000 mV
ratio, and control
condition by the en-
gine-ECU.2,500 r/min400 mV or less
(Changes)
600 ± 1,000 mV
12Air flow
sensor*1
Engine coolant
temperature:
80 ± 95C

Lamps and all
accessories: OFF
Engine is idling22 ± 48 Hz
<4G63>
19 ± 45 Hz
<4G64>±±
accessories: OFF

Transmission:
Neutral (A/T:
P range)2,500 r/min80 ± 120 Hz
<4G63>
67 ± 107 Hz
<4G64>
Engine is racedFrequency
increases in
response to
racing

MPI ± Troubleshooting13A-62
ACTUATOR TEST REFERENCE TABLE13100900210
Item
No.Inspection
itemDrive contentsInspection contentsNormal conditionInspection
procedure
No.Reference
page
01InjectorsCut fuel to No.1,
No.3 injectorEngine:
After having warmed up/En-
gine is idling
(Cut the fuel supply to each
Idling condition
becomes different
(becomes unsta-
ble)
Code No.
4113A-19
02Cut fuel to No.2,
No.4 injector(Cut the fuel supply to each
injector in turn and check
cylinders which don't affect
idling.)
ble).
07Fuel pumpFuel pump
operates and
fuel is recircu-
lated.
Engine:
Cranking

Fuel
pump:
Forced
driving
Inspect
accord-
Pinch the
return hose
with fingers
to feel the
pulse of the
fuel being
recirculated.Pulse is felt.Procedure
No. 2413A-40
accord-
ing to
both the
above
condi-
tions.
Listen near
the fuel tank
for the
sound of fuel
pump
operation.Sound of operation
is heard.
08Purge
control
solenoid
valveSolenoid valve
turns from OFF
to ON.Ignition switch: ONSound of operation
can be heard when
solenoid valve is
driven.Procedure
No. 3213A-45
10EGR
control
solenoid
valveSolenoid valve
turns from OFF
to ON.Ignition switch: ONSound of operation
can be heard when
solenoid valve is
driven.Procedure
No. 3313A-46

MPI ± On-vehicle Service13A-83
14. Stop the engine and check change of fuel pressure gauge
reading. Normal if the reading does not drop within 2
minutes. If it does, observe the rate of drop and
troubleshoot and repair according to the table below.
SymptomProbable causeRemedy
Fuel pressure drops gradually after
engine is stopped
Leaky injectorReplace injector
engine is sto ed
Leaky fuel regulator valve seatReplace fuel pressure regulator
Fuel pressure drops sharply
immediately after engine is stoppedCheck valve in fuel pump is held openReplace fuel pump
15. Release residual pressure from the fuel pipe line. (Refer
to P.13A-84.)
16. Remove the fuel pressure gauge and special tool from
the delivery pipe.
Caution
Cover the hose connection with rags to prevent splash
of fuel that could be caused by some residual pressure
in the fuel pipe line.
17. Replace the O-ring at the end of the fuel high pressure
hose with a new one. Furthermore, apply engine oil to
the new O-ring before replacement.
18. Fit the fuel high pressure hose over the delivery pipe
and tighten the bolt to specified torque.
Tightening torque: 5 Nm
19. Check for fuel leaks.
(1) Apply the battery voltage to the fuel pump drive
terminal to drive the fuel pump.
(2) Under fuel pressure, check the fuel line for leaks.

MPI ± Injector13A-93
REMOVAL SERVICE POINT
A
DELIVERY PIPE/INJECTOR REMOVAL
Remove the delivery pipe (with the injectors attached to it).
Caution
Care must be taken, when removing the delivery pipe,
not to drop the injector.
INSTALLATION SERVICE POINT

AINJECTOR/FUEL PRESSURE REGULATOR/
HIGH-PRESSURE FUEL HOSE INSTALLATION
(1) Apply a drop of new engine oil to the O-ring.
Caution
Be sure not to let engine oil in the delivery pipe.
(2) While turning the injector, high-pressure fuel hose and
fuel pressure regulator to the right and left, install the
delivery pipe, while being careful not to damage the O-ring.
After installing, check that the hose turns smoothly.
(3) If it does not turn smoothly, the O-ring may be trapped,
remove the fuel pressure regulator and then re-insert
it into the delivery pipe and check once again.
(4) Tighten the high-pressure fuel hose and fuel pressure
regulator to the specified torque.
Tightening torque:
9 Nm (Fuel pressure regulator)
5 Nm (High-pressure fuel hose)

I
N JE C TIO N N O ZZLE 13300270010
R EM OVA L A ND IN STA LLA TIO N 4
.9 N m 1
2 N m 1
6 N m 4
.9 N m 2
9 N m 4
9 ± 5 9 N m 1
2
3
4
5
6
7
8
9
1 0
1 1 3
3
3
R em oval s te p s
1 . A cce le ra to r c a ble c o nnectio n
2 . Thro ttle c a ble c o nnectio n < A /T >
3 . In je ctio n p ip e c la m p
 A
4. In je ctio n p ip e
5 . Fuel r e tu rn h ose
 B
6. N ut 
B
7. Fuel r e tu rn p ip e
8 . Fuel r e tu rn p ip e g aske t
 C
9. In je ctio n n ozzle a sse m bly

A 10. H old er g aske t

A 11 . N ozzle g aske t
R EM OVA L S ER VIC E P O IN TS
 A
IN JE C TIO N P IP E D IS C O NNEC TIO N
W hen lo ose nin g n uts a t b oth e nds o f in je ctio n p ip e, h old
t h e d eliv e ry h old er ( fo r p um p s id e) a nd th e in je ctio n n ozzle
a sse m bly ( fo r n ozzle s id e) w it h w re nch a nd lo ose n n ut. N
ut

I
N JE C TIO N P U M P 13300240011
R EM OVA L A ND IN STA LLA TIO N 7
9 ± 8 8 N m 4
.9 N m
1 2
3
4
5
6
7
8
9 10 2
R em oval s te p s
1 . Fuel in je ctio n p um p w ir in g h arn ess
2 . W ate r h ose c o nnectio n < V ehic le s
w it h c o ld s ta rt d evic e >
3 . Fuel h ose s
4 . Leve r p osit io n s w it c h < A /T , A /C >
5 . A cce le ra to r c a ble c o nnectio n 6
. Thro ttle c a ble c o nnectio n < A /T >
7 . B oost h ose c o nnectio n < 4W D>
 A
8. Fuel in je ctio n p ip e
 B
9. Fuel in je ctio n p um p s p ro cke t
1 0. Fuel in je ctio n p um p