1997 MITSUBISHI TRITON fuel pressure

MPI ± Troubleshooting13A-51
INSPECTION PROCEDURE 40
MUT-II: Check if hesitation, sug, stumble or poor acceleration occurs.
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOS-
TIC CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

MPI ± Troubleshooting13A-52
INSPECTION PROCEDURE 41
MUT-II: Check if surge occurs.
MUT-II Data list
26 Idle position switch (Refer to P.13A-57.)NGCheck the idle position switch system.
(Refer to P.13A-40, INSPECTION PROCEDURE 25.)
OK
MUT-II Data list
13 Intake air temperature sensor (Refer to P.13A-57.)NGCheck the intake air sensor system. (Refer to P.13A-12, INSPEC-
TION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list
25 Barometric pressure sensor (Refer to P.13A-57.)NGCheck the barometric pressure sensor system. (Refer to P.13A-18,
INSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list
21 Engine coolant temperature sensor (Refer to P.13A-57.)NGCheck the engine coolant temperature sensor system.
(Refer to P.13A-14, INSPECTION PROCEDURE FOR DIAGNOSIS
CODE 21.)
OK
MUT-II Data list
14 Throttle position sensor (Refer to P.13A-57.)NGCheck the throttle position sensor system. (Refer to P.13A-13, IN-
SPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Actuator test
10 EGR control solenoid valve (Refer to P.13A-62.)NGCheck the EGR control solenoid valve system.
(Refer to P.s13A-46, INSPECTION PROCEDURE 33.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 600 ± 1,000 mV during sudden racingNGCheck the oxygen sensor system. (Refer to P.13A-11, INSPECTION
PROCEDURE FOR DIAGNOSIS CODE 11.)
OK
MUT-II Data list
11 Oxygen sensor
OK:Changes between 0 ± 400 mV and 600 ± 1,000 mV during
idlingNGCheck the fuel pressure.
(Refer to P.13A-81.)OK1. Inspect the intake of
air into the air intake
system

Broken intake
manifold gasket

Broken vacuum
hose

PCV valve does
not operate.

Broken air intake
hose
2. Check the injector for
clog.

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)