Mitsubishi Pajero Pinin. Manual - part 128

MPI <4G9> – 

On-vehicle Service

13C-98

7.

If not within the standard value range, turn the speed
adjusting screw (SAS) to make the necessary adjustment.

8.

Press the MUT-

II

 clear key, and release the ISC servo

from the Actuator test mode.

NOTE
Unless the ISC servo is released, the Actuator test mode
will continue 27 minutes.

9.

Turn the ignition switch to LOCK (OFF) position.

10. Disconnect the MUT-

II.

11. Start the engine again and let it run at idle speed for

about 10 minutes; check that the idling condition is normal.

FUEL PRESSURE TEST

1.

Release residual pressure from the fuel pipe line to prevent
fuel gush out. (Refer to P.13C-70.)

2.

Disconnect the high-pressure fuel hose at the delivery
pipe side.

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.

3.

Remove the union joint and bolt from the special tool
(adapter hose) and instead attach the special tool (hose
adapter) to the adapter hose.

4.

Install the special tool (for measuring the fuel pressure)
that was set up in step 3.
<When using the fuel pressure gauge set (special tool)>
(1) Install the special tool (for measuring the fuel pressure)

between the high-pressure fuel hose and the delivery
pipe.

(2) Install the fuel pressure gauge set (special tool) on

the special tool (for measuring the fuel pressure)
putting the gasket between them.

(3) Connect the lead wire of the fuel pressure gauge set

(special tool) to the power supply (cigarette lighter
socket) and to the MUT-

II

.

Delivery pipe

High-pressure
fuel hose

MB991637

Gasket

MD998709

MD998742

High-pressure
fuel hose

Delivery
pipe

MPI <4G9> – 

On-vehicle Service

13C-99

<When using the fuel pressure gauge>
(1) Install the fuel pressure gauge on the special tool

(for measuring the fuel pressure) putting a suitable
O-ring or gasket between them.

(2) Install the special tool which was set up in step (1)

between the high-pressure fuel hose and the delivery
pipe.

5.

Connect the MUT-

II

 to the diagnosis connector.

6.

Turn the ignition switch to ON. (But do not start the engine.)

7.

Select “Item No.07” from the MUT-

II

 Actuator test to drive

the fuel pump. Check that there are no fuel leaks from
any parts.

8.

Finish the actuator test or turn the ignition switch to LOCK
(OFF) position.

9.

Start the engine and run at idle.

10. Measure fuel pressure while the engine is running at idle.

Standard value: Approx. 265 kPa

11. Disconnect the vacuum hose from the fuel pressure

regulator and measure fuel pressure with the hose end
closed by a finger.

Standard value: 324–349 kPa

12. Check to see that fuel pressure at idle does not drop

even after the engine has been raced several times.

13. Racing the engine repeatedly, hold the fuel return hose

lightly with fingers to feel that fuel pressure is present
in the return hose.

NOTE
If the fuel flow rate is low, there will be no fuel pressure
in the return hose.

14. If any of fuel pressure measured in steps 10 to 13 is

out of specification, troubleshoot and repair according to
the table below.

Symptom

Probable cause

Remedy

D

Fuel pressure too low

D

Fuel pressure drops after racing

Clogged fuel filter

Replace fuel filter

D

Fuel pressure drops after racing

D

No fuel pressure in fuel return
hose

Fuel leaking to return side due to poor
fuel regulator valve seating or settled
spring

Replace fuel pressure regulator

Low fuel pump delivery pressure

Replace fuel pump

Fuel pressure too high

Binding valve in fuel pressure 
regulator

Replace fuel pressure regulator

Clogged fuel return hose or pipe

Clean or replace hose or pipe

Same fuel pressure when vacuum
hose is connected and when 
disconnected

Damaged vacuum hose or clogged
nipple

Replace vacuum hose or clean nipple

Fuel pressure gauge set

O-ring or gasket

MD998709

MD999742

High-pressure
fuel hose

Delivery
pipe

MPI <4G9> – 

On-vehicle Service

13C-100

15. 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.

Symptom

Probable cause

Remedy

Fuel pressure drops gradually after
engine is stopped

Leaky injector

Replace injector

engine is stopped

Leaky fuel regulator valve seat

Replace fuel pressure regulator

Fuel pressure drops sharply 
immediately after engine is stopped

Check valve in fuel pump is held open

Replace fuel pump

16. Release residual pressure from the fuel pipe line. 

(Refer to P.13C-70.)

17. 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.

18. 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.

19. Fit the fuel high pressure hose over the delivery pipe and

tighten the bolt to specified torque.

Tightening torque: 9.0 

±

 2.0 Nm

20. Check for any fuel leaks by following the procedure in

step 7.

21. Disconnect the MUT-

II

.

FUEL PUMP CONNECTOR DISCONNECTION
(HOW TO REDUCE THE FUEL PRESSURE)

When removing the fuel pipe, hose, etc., since fuel pressure
in the fuel pipe line is high, do the following operation so
as to release the fuel pressure in the line and prevent fuel
from running out.
1.

Remove the fuel pump relay.

2.

After starting the engine and letting it run until it stops
naturally, turn the ignition switch to LOCK (OFF) position.

3.

Install the fuel pump relay.

FUEL PUMP OPERATION CHECK

Refer to  GROUP 13A – On-vehicle Service.

Fuel pump relay

MPI <4G9> – 

On-vehicle Service

13C-101

COMPONENT LOCATION

Name

Symbol

Name

Symbol

A/C relay

A

Engine warning lamp (check engine lamp)

O

A/C switch

Q

Idle speed control servo

B

Air flow sensor (With intake air temperature
sensor and barometric pressure sensor)

J

Ignition coil

N

sensor and barometric pressure sensor)

Ignition failure sensor

E

Camshaft position sensor

F

Inhibitor switch <A/T>

G

Control relay and fuel pump relay

A

Injectors

D

Crank angle sensor

L

Oxygen sensor (front)

I

Detonation sensor

K

Oxygen sensor (rear)

S

Diagnosis connector

P

Power steering fluid pressure switch

M

EGR control solenoid valve

C

Purge control solenoid valve

C

Engine coolant temperature sensor

H

Throttle position sensor

B

Engine-ECU

R

Vehicle speed sensor

T

O

P

Q

R

S

K

L

M

N

A

B

C

D

E

F

G H

I

J

T

T