Mitsubishi Grandis. Manual — part 785

ON-VEHICLE SERVICE

MULTIPORT FUEL INJECTION (MPI)

13A-391

OXYGEN SENSOR CHECK

M1131005000947

OXYGEN SENSOR (FRONT)

1. Disconnect the oxygen sensor connector and

connect the special tool Test harness (MB991316)
to the connector on the oxygen sensor side.

2. Make sure that there is continuity (4.5

− 8.0 Ω at

20

°C) between terminal No. 1 (red clip of special

tool) and No. 3 (blue clip of special tool) on the
oxygen sensor connector.

3. If there is no continuity, replace the oxygen

sensor.

4. Warm up the engine until engine coolant is 80

°C

or higher.

5. Perform a tracing for 5 minutes or more with the

engine speed of 4,500 r/min.

6. Connect a digital voltage meter between terminal

No. 2 (black clip of special tool) and No. 4 (white
clip of special tool).

7. While repeatedly racing the engine, measure the

oxygen sensor output voltage.

Standard value:

CAUTION

• Be very careful when connecting the jumper

wire; incorrect connection can damage the
oxygen sensor.

• Be careful the heater is broken when voltage

of beyond 8V is applied to the oxygen sensor
heater.

NOTE: If the sufficiently high temperature (of
approximate 400

°

C or more) is not reached

although the oxygen sensor is normal, the output
voltage would be possibly low although the rich
air-fuel ratio. Therefore, if the output voltage is
low, use a jumper wire to connect the terminal No.
1 (red clip of special tool) and the terminal No. 3
(blue clip of special tool) of the oxygen sensor
with a (+) terminal and (-) terminal of 8 V power
supply respectively, then check again.

8. If the sensor is defective, replace the oxygen

sensor.

AK300694

1

2

3

4

AC

Equipment side
connector

Cylinder 1, 4
oxygen sensor (front)

Cylinder 1, 4
oxygen sensor
connector (front)

AK300703

1

2

3

4

AC

Equipment side
connector

Cylinder 2, 3
oxygen sensor (front)

Cylinder 2, 3
oxygen sensor
connector (front)

AKX01624

Red

Blue

MB991316

Oxygen
sensor
equipment
side connector

AR

Engine

Oxygen
sensor
output
voltage

Remarks

When
racing the
engine

0.6

− 1.0 V If you make the air-fuel

ratio rich by racing the
engine repeatedly, a
normal oxygen sensor
will output a voltage of
0.6

− 1.0 V.

AKX01624

Black

White

MB991316

Oxygen
sensor
equipment
side connector

AP

ON-VEHICLE SERVICE

MULTIPORT FUEL INJECTION (MPI)

13A-392

NOTE: For removal and installation of the oxygen
sensor, refer to GROUP 15

−

Exhaust Manifold.

P.15-7

.

OXYGEN SENSOR (REAR)

1. Disconnect the oxygen sensor connector and

connect the special tool Test harness
(MD998464) to the connector on the oxygen
sensor side.

2. Make sure that there is continuity (11

− 18 Ω at

20

°C) between terminal No.1 (red clip of special

tool) and No. 3 (blue clip of special tool) on the
oxygen sensor connector.

3. If there is no continuity, replace the oxygen

sensor.

4. Warm up the engine until engine coolant is 80

°C

or higher.

5. Perform a tracing for 5 minutes or more with the

engine speed of 4,500 r/min.

6. Connect a digital voltage meter between terminal

No.2 (black clip of special tool) and No. 4 (white
clip of special tool).

7. While repeatedly racing the engine, measure the

oxygen sensor output voltage.

Standard value:

AK300695

1

2

3

4

AC

Equipment side
connector

Cylinder 1, 4
oxygen sensor (rear)

Cylinder 1, 4
oxygen sensor
connector (rear)

AK300704

1

2

3

4

AC

Equipment side
connector

Cylinder 2, 3
oxygen sensor (rear)

Cylinder 2, 3
oxygen sensor
connector (rear)

Engine

Oxygen
sensor
output
voltage

Remarks

When
racing the
engine

0.6

− 1.0 V If you make the air-fuel

ratio rich by racing the
engine repeatedly, a
normal oxygen sensor
will output a voltage of
0.6

− 1.0 V.

AKX01624

Red

Blue

MD998464

Oxygen
sensor
equipment
side connector

AF

AKX01624

Black

White

MD998464

Oxygen
sensor
equipment
side connector

AS

ON-VEHICLE SERVICE

MULTIPORT FUEL INJECTION (MPI)

13A-393

CAUTION

• Be very careful when connecting the jumper

wire; incorrect connection can damage the
oxygen sensor.

• Be careful the heater is broken when voltage

of beyond 12 V is applied to the oxygen
sensor heater.

NOTE: If the sufficiently high temperature (of
approximate 400

°

C or more) is not reached

although the oxygen sensor is normal, the output
voltage would be possibly low although the rich
air-fuel ratio. Therefore, if the output voltage is
low, use a jumper wire to connect the terminal
No.2 and the terminal No. 1 of the oxygen sensor
with a (+) terminal and (-) terminal of 12 V power
supply respectively, then check again.

8. If the sensor is defective, replace the oxygen

sensor.
NOTE: For removal and installation of the oxygen
sensor, refer to GROUP 15

−

Exhaust Pipe and

Main Muffler

P.15-9

.

INJECTOR CHECK

M1131005200792

Check the Operation Sound

1. Use a stethoscope to listen to the operation sound

(clicking) of the injectors while the engine is idling
or cranking.

CAUTION

Beware that the operation sounds of other
injectors can be heard even if the injector that is
being inspected might not be operating.
2. Verify that the operation sound increases with the

engine speed.
NOTE: If the operating sound cannot be heard,
inspect the injector actuation circuit.

Measurement of Resistance between
Terminals

1. Disconnect the injector connector.
2. Measure the resistance between terminals.

Standard value: 10.5

− 13.5 Ω (at 20°C)

3. Connect the injector connector.

Check the Injection Condition

1. Following the steps below, bleed out the residual

pressure within the fuel pipe line to prevent flow of
the fuel (Refer to

P.13A-386

).

2. Remove the injector.

3. Assemble the following special tools as shown in

Fig.

• Injector test set (MD998706)

• Injector test harness (MB991607)

• Injector test adaptor (MD998741)

• Injector test holder assembly (MB991976)

4. Connect the MUT-II/III to the diagnosis connector.
5. Turn the ignition switch to "ON" position (But do

not start the engine).

6. Select "Item No. 07" from the MUT-II/III actuator

test to drive the fuel pump.

7. Activate the injector and check the atomized

spray condition of the fuel.
The condition can be considered satisfactory
unless it is extremely poor.

8. Stop the actuation of the injector, and check for

leakage from the injector’s nozzle.

Standard value: 1 drop or less per minute

AK300696

1 2

AC

Injector

Equipment side connector

AK301464

MD998741

MD998706

MB991976

MB991607

AC

High-pressure
fuel hose

Fuel pressure
regulator

Return hose

Battery

Injector

AK301465AC

High-pressure
fuel hose

Fuel pressure
regulator

Return hose

Battery

Injector

ON-VEHICLE SERVICE

MULTIPORT FUEL INJECTION (MPI)

13A-394

9. Without the fuel pump operation, operate the

injector to draw the fuel out.

10.If the spraying is extremely poor or the fuel

leakage from the injector nozzle deviates from the
standard value, replace the injector.

11.Disconnect the MUT-II/III.

THROTTLE VALVE CONTROL SERVO
CHECK

M1131051000177

OPERATION CHECK

1. Remove the air intake hose from the throttle body.
2. Turn the ignition switch to "ON" position.
3. Operate the accelerator pedal and confirm that

the throttle valve is opening and closing
accordingly.

CHECK THE COIL RESISTANCE

1. Disconnect the electronic-controlled throttle valve

connector.

2. Measure the resistance between terminals No. 1

and No. 2 at the throttle valve control servo
connector.

Standard value: 0.3

− 100 Ω (at 20°C)

3. If resistance is outside the standard value, replace

the throttle body assembly.

OIL CONTROL VALVE CHECK

M1131053200111

OPERATION CHECK

1. Disconnect the oil control valve connector.

CAUTION

To prevent the coil from burning, keep the
duration of the voltage application as short as
possible.
2. Apply battery voltage to the terminals of the

connector at the oil control valve, and make sure
the oil control valve makes a clicking sound.

MEASUREMENT OF RESISTANCE
BETWEEN TERMINALS

1. Disconnect the oil control valve connector.
2. Measure the resistance between the terminals of

the connector at the oil control valve.

Standard value: 6.9

− 7.9 Ω (at 20°C)

3. If resistance is outside the standard value, replace

the oil control valve.

AK300697

6

1 2 3 4 5

AC

Equipment side connector

Electronic-controlled
throttle valve

AK300698

1 2

AC

Oil control valve

Equipment side connector