Mitsubishi Galant. Manual — part 190

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-441

13.Stop the engine and observe fuel pressure gauge reading. It

is normal if the reading does not drop within two minutes. If it
does, observe the rate of drop and troubleshoot and repair
according to the table below. Start, then stop the engine.

(1) Squeeze the fuel return line closed to confirm leak-down

occurs from defective fuel pressure regulator.

(2) Squeeze the fuel supply line closed to confirm leak-down

occurs from defective fuel pump check valve.

(3) If pressure continues to drop with both fuel lines

squeezed closed, injector(s) are leaking.

14.14.Release residual pressure from the fuel pipe line. (Refer

to

P.13A-442

.)

WARNING

Cover the hose connection with shop towels to
prevent splash of fuel that could be caused by some
residual pressure in the fuel pipe line.

15.Remove the fuel pressure gauge, and special tools

MD998709 and MD998742 from the fuel rail.

16.Replace the O-ring at the end of the high-pressure fuel hose

with a new one.

17.Fit the high-pressure fuel hose into the fuel rail and tighten

the bolts to specified torque.

Tightening torque: 4.9

±±±±

1.0 (44

±±±±

8 in-lb)

18.Check for fuel leaks.

(1) Use scan tool MB991502 to operate the fuel pump.
(2) Check the fuel line for leaks, and repair as needed.

19.Disconnect scan tool MB991502.

Fuel pressure too high

Binding valve in fuel pressure reg-
ulator

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 dis-
connected

Damaged vacuum hose or
clogged nipple

Replace vacuum hose or clean
nipple

Defective fuel pressure regulator

Replace fuel pressure regulator

SYMPTOM

PROBABLE CAUSE

REMEDY

Fuel pressure drops gradually af-
ter engine is stopped

Leaky injector

Replace injector

Leaky fuel regulator valve seat

Replace fuel pressure regulator

Fuel pressure drops sharply imme-
diately after engine is stopped

Check valve in fuel pump is held
open

Replace fuel pump

SYMPTOM

PROBABLE CAUSE

REMEDY

AK000120

AK000120

HIGH-
PRESSURE
FUEL HOSE

MD998709

MD998742

FUEL RAIL

AB

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-442

FUEL PUMP CONNECTOR
DISCONNECTION(HOW TO REDUCE
PRESSURIZED FUEL LINES)

M1131000900105

WARNING

When removing the fuel pipe, etc., release fuel
pressure to prevent fuel spray.

1. Disconnect the fuel pump relay.

2. Start the engine and let it run until it stops naturally. Turn the

ignition switch to the "LOCK" (OFF) position.

3. Connect the fuel pump relay.

FUEL PUMP OPERATION CHECK

M1131002000090

Required Special Tool:
MB991502: Scan Tool (MUT-II)
1. Check the operating of the fuel pump by using scan tool

MB991502 to force-drive the fuel pump.

2. If the fuel pump will not operate, check by using the

following procedure. If normal, check the fuel pump drive
circuit.

(1) Turn the ignition switch to the "LOCK" (OFF) position.
(2) Remove the fuel pump relay, and apply battery voltage to

harness-side connector terminal number 2. Check that an
operating sound can be heard from the fuel pump.

NOTE: As the fuel pump is an in-tank type, the fuel pump
sound is hard to hear. Remove the fuel tank filler tube cap
and check from the tank inlet.

(3) Check for fuel pressure by pinching the fuel hose with

fingertips.

(4) Install the fuel pump relay.

AC000229

FUEL PUMP
RELAY

AB

AC003081 AB

16 PIN

MB991502

AC000230

FUEL PUMP RELAY

AB

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-443

MULTIPORT FUEL INJECTION (MFI) RELAY AND
FUEL PUMP RELAY CONTINUITY CHECK

M1131009900083

INTAKE AIR TEMPERATURE SENSOR CHECK

M1131002800074

1. Disconnect the volume air flow sensor connectors.

2. Measure resistance between terminals 5 and 6.

Standard value:

5.3

−−−−

6.7 k

Ω

Ω

Ω

Ω

[at 0

°°°°

C (32

°°°°

F)]

2.3

−−−−

3.0 k

Ω

Ω

Ω

Ω

[at 20

°°°°

C

(68

°°°°

F)]

1.0

−−−−

1.5 k

Ω

Ω

Ω

Ω

[at 40

°°°°

C

(104

°°°°

F)]

0.30

−−−−

0.42 k

Ω

Ω

Ω

Ω

[at 80

°°°°

C (176

°°°°

F)]

3. If not within specifications, replace the volume air flow

sensor.

4. Measure resistance while heating the sensor using a hair

dryer.

Normal condition:

5. If resistance does not decrease as heat increases, replace

the volume air flow sensor assembly.

ENGINE COOLANT TEMPERATURE SENSOR
CHECK

M1131003100056

CAUTION

Be careful not to touch the connector (resin section) with
the tool when removing and installing.
1. Drain engine coolant, then remove the engine coolant

temperature sensor.

BATTERY
VOTAGE

BATTERY POWER
SUPPLY
TERMINAL

SPECIFIED
CONDITION

Not supplied

-

2-4

Supplied

2-4

1-3

AK000599

MFI RELAY SIDE
CONNECTOR

AB

2

3 4

1

AKX01407AC

VOLUME AIR FLOW
SENSOR CONNECTOR

1 2 3 4 5 6 7

TEMPERATURE

RESISTANCE (k

Ω

Ω

Ω

Ω

)

Higher

Smaller

AKX01621 AB

INTAKE AIR
TEMPERATURE
SENSOR

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-444

2. With the temperature sensing portion of engine coolant

temperature sensor immersed in hot water, check the
resistance.

Standard value:

5.1

−−−−

6.5 k

Ω

Ω

Ω

Ω

[at 0

°°°°

C (32

°°°°

F)]

2.1

−−−−

2.7 k

Ω

Ω

Ω

Ω

[at 20

°°°°

C (68

°°°°

F)]

0.9

−−−−

1.3 k

Ω

Ω

Ω

Ω

[at 40

°°°°

C (104

°°°°

F)]

0.26

−−−−

0.36 k

Ω

Ω

Ω

Ω

[at 80

°°°°

C (176

°°°°

F)]

3. If resistance deviates from the standard value greatly,

replace the sensor.

4. Apply 3M



AAD part number 8731 or equivalent to threaded

portion.

5. Install the engine coolant temperature sensor and tighten it

to the specified torque.

Tightening torque: 29

±±±±

10 N

⋅⋅⋅⋅

m (22

±±±±

7 ft-lb)

THROTTLE POSITION SENSOR CHECK

M1131003200053

Required Special Tool:
MB991348: Test Harness Set
Checking the Terminal Resistance
1. Disconnect the throttle position sensor connector.

2. Measure resistance between the throttle position sensor

side connector terminal 1 and terminal 4.

Standard value: 3.5

−−−−

6.5 k

Ω

Ω

Ω

Ω

3. Measure resistance between the throttle position sensor

side connector terminal 1 and terminal 3.

Normal condition:

4. If resistance is outside the standard value, or if it doesn't

change smoothly, replace the throttle position sensor.

NOTE: After replacement, the throttle position sensor should
be adjusted. (Refer to

P.13A-437

.)

AKX01622

AKX01623 AB

Throttle valve slowly open
until fully open from the idle
position

Changes smoothly in
proportion to the opening
angle of the throttle valve

AKX01413

THROTTLE POSITION
SENSOR CONNECTOR

1 2 3 4

AB