Mitsubishi Galant (2004+). Manual - part 1360

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1133

THROTTLE BODY (THROTTLE VALVE AREA) 
CLEANING

M1131001000503

WARNING

If the  throttle valve is operation in service, a finger 
might be injured as the result of being caught by the 
throttle valve. Make sure that the ignition switch is 
surely in "LOCK"(OFF) position before the service in 
order that the throttle valve cannot be operation.

1. Remove the throttle body.

CAUTION

• Do not spray the cleaning solvent directly to the throttle 

valve.

• Make sure the cleaning solvent does not enter the 

motor and the sensor through the shaft.

2. Spray cleaning solvent on a clean cloth.
3. Wipe off the dirt around the throttle valve with the cloth 

sprayed with cleaning solvent.

4. Attach the throttle body.

FUEL PRESSURE TEST

M1131001900584

Required Special Tools:

• MB991958: Scan tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: USB Cable

• MB991910: Main Harness A

• MB991637: Fuel Pressure Gauge Set

• MD998709: Adaptor Hose

• MD998742: Hose Adaptor

1. Release residual pressure from the fuel line to prevent fuel 

spray. (Refer to 

P.13B-1136

.)

WARNING

To prevent a fire, cover the hose connection with 
shop towels to prevent splashing of fuel that could be 
caused by some residual pressure in the fuel pipe 
line.

2. Disconnect the fuel high-pressure hose at the fuel rail side.
3. Assemble the fuel pressure measurement tools as follows.

AK203312AB

FUEL 
HIGH-PRESSURE 
HOSE 

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1134

<When using the fuel pressure gauge>

1. Remove the union joint and bolt from special tool 

MD998709 (adapter hose) and instead attach special tool 
MD998742 (hose adapter) to the adapter hose.

2. Place a suitable O-ring or gasket on the assembled special 

tools MD998709 and MD998742 and install the fuel pres-
sure gauge.

3. Install the assembled fuel pressure measurement tools 

between the fuel rail and fuel high-pressure hose.

<When using special tool MB991637 (fuel pressure gauge 

set)>

1. Remove the union joint and bolt from special tool 

MD998709 (adapter hose) and instead attach special tool 
MD998742 (hose adapter) to the adapter hose.

2. Install special tool MB991637 (fuel pressure gauge set) into 

assembled special tools MD998709 and MD998742 via a 
gasket.

3. Install the assembled fuel pressure measurement tools 

between the fuel rail and fuel high-pressure hose.

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
4. Connect scan tool MB991958 to the data link connector.
5. Use Actuator test 07 to drive the fuel pump. Check that there 

is no fuel leaking from any section when the fuel pump is 
operating.

6. Stop the fuel pump.
7. Start the engine and run at idle.
8. Measure fuel pressure while the engine is running at idle.

Standard value: Approximately 324 kPa (95.7 in.Hg) at 
curb idle

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

after the engine has been revved several times.

AKX01457AH

FUEL PRESSURE 
GAUGE

O-RING OR GASKET

MD998709

MD998742

FUEL 
RAIL 

FUEL
HIGH-PRESSURE
HOSE

AKX01458

MB991637

O-RING OR GASKET

MD998709

MD998742

FUEL
RAIL

AI

FUEL
HIGH-PRESSURE
HOSE

AC305412

AB

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1135

10.If any of fuel pressure measured in steps 8 to 9 is out of 

specification, troubleshoot and repair according to the table 
below.

11.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 supply line closed to confirm leak-down 

occurs from defective fuel pump check valve.

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

squeezed closed, injector(s) are leaking.

12.Release residual pressure from the fuel pipe line. (Refer to 

P.13B-1136

.)

WARNING

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

13.Remove the fuel pressure gauge, and special tools 

MD998709, MD998742 and MB991637 from the fuel rail.

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

with a new one.

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

the bolts to specified torque.

Tightening torque: 5.0 

± 1.0 N⋅m (44 ± 8 in-lb)

16.Check for fuel leaks.

(1) Use scan tool MB991958 to operate the fuel pump.
(2) Check the fuel line for leaks and repair as needed.

17.Disconnect scan tool MB991958.

SYMPTOM

PROBABLE CAUSE

REMEDY

• Fuel pressure too low

• Fuel pressure drops after racing

Clogged fuel filter

Replace fuel filter

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

SYMPTOM

PROBABLE CAUSE

REMEDY

Fuel pressure drops gradually 
after engine is stopped

Leaky injector

Replace injector

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

AKX01460AB

MD998709

FUEL 
RAIL

MD998742

HIGH-
PRESSURE
FUEL HOSE

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-1136

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

M1131000900633

Refer to GROUP 13A, On-vehicle Service 

− Fuel Pump Relay 

Disconnection (How to Reduce Pressurized Fuel Lines) 

P.13A-1107

.

FUEL PUMP OPERATION CHECK

M1131002000700

Refer to GROUP 13A, On-vehicle Service 

− Fuel Pump Opera-

tion Check 

P.13A-1108

.

MULTIPORT FUEL INJECTION (MFI) RELAY AND 
THROTTLE ACTUATOR CONTROL MOTOR 
RELAY CONTINUITY CHECK

M1131050000345

Inspect the MFI relay and throttle actuator control motor relay 
for continuity in accordance with the chart shown below.

BATTERY 
VOLTAGE

TERMINAL NO. 
TO BE 
CONNECTED TO 
BATTERY

TERMINAL NO. 
TO BE 
CONDUCTED

Not supplied

−

2 

− 3

Supplied

2 

−  3

1 

− 4

AK100599

1 2
3 4

1 2
3 4

MFI RELAY OR 
THROTTLE 
ACTUATOR
CONTROL 
MOTOR RELAY 
SIDE CONNECTOR

MFI RELAY  OR THROTTLE 
ACTUATOR CONTROL MOTOR 
RELAY SIDE CONNECTOR

AC