Mitsubishi Galant. Manual — part 324

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-521

4. If not within the standard value range, adjust by loosening

throttle position sensor mounting bolts and turning the
throttle position sensor body. After adjusting, tighten the
bolts securely.

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

6. Disconnect scan tool MB991502, and connect the throttle

position sensor connector. When the scan tool is not used,
remove special tool MB991348, and connect the throttle
position sensor connector.

BASIC IDLE SPEED ADJUSTMENT

M1131001800093

Required Special Tool:
MB991502: Scan Tool (MUT-II)

NOTE: The standard idling speed has been adjusted with the
speed adjusting screw (SAS), by the manufacturer. There
should be no need for readjustment.

NOTE: If the adjustment has been changed by mistake, the idle
speed may become too high or the idle speed may drop too low
when loads A/C, defogger, etc. are placed on the engine. If this
occurs, adjust by the following procedure.

NOTE: The adjustment, if made, should be made after first
confirming that the spark plugs, the injectors, the idle air control
motor, compression, etc., are all normal.
1. The vehicle should be prepared as follows before the

inspection and adjustment.

•

Engine coolant temperature: 80

−

95

°

C(176

−

203

°

F

)

•

Lights, electric cooling fan and accessories: OFF

•

Transaxle: "P" range

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
2. Connect scan tool MB991502 to the data link connector (16-

pin).

NOTE: When scan tool MB991502 is connected, the
diagnostic test mode control terminal should be grounded.

3. Start the engine and run at idle.

4. Select the item number 30 of the scan tool Actuator test.

NOTE: Use the scan tool to hold the IAC motor at the basic
step to adjust the basic idle speed.

5. Check the idle speed.

NOTE: The engine speed may be 20 to 100 r/min lower than
indicated above for a new vehicle [driven approximately 500
km (300 mile) or less], but no adjustment is necessary.

NOTE: If the engine stalls or the engine speed is low even
though the vehicle has been driven approximately 500 km
(300 mile) or more, it is probable that deposits are adhered
to the throttle valve, so clean it. (Refer to

P.13B-520

)

AKX01636AB

TERMINAL 3
(SENSOR OUTPUT)

TERMINAL 1
(SENSOR
GROUND)

MB991348

AC003081 AB

16 PIN

MB991502

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-522

Standard value: 700

±±±±

50 r/min

6. If not within the standard value range, turn the speed

adjusting screw (SAS) to make the necessary adjustment.

7. Press the scan tool clear key, and release the IAC motor

Actuator test mode.

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

NOTE: Unless the IAC motor is released, the Actuator test
mode will continue for 27 minutes.

9. Disconnect scan tool MB991502.

10.Start the engine again and let it idle for about 10 minutes.

Check that the idling condition is normal.

FUEL PRESSURE TEST

M1131001900089

Required Special Tools:
MB991502: Scan Tool (MUT-II)
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-524

.)

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 high-pressure fuel hose at the fuel rail side.

3. Assemble the fuel pressure measurement tools as follows.

<When using the fuel pressure gauge>

1. Remove the union joint and bolt from special tool

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

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

tools MD998709 and MD998742 and install the fuel
pressure gauge.

3. Install the assembled fuel pressure measurement tools

between the fuel rail and high-pressure fuel hose.

<When using the special tool MB991637 (fuel pressure

gauge set)>

1. Remove the union joint and bolt from special tool

MD998709 (adaptor hose) and instead attach special tool
MD998742 (hose adaptor) to the adaptor 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 the high-pressure fuel hose.

AK000115AB

SPEED ADJUSTING SCREW

AK000117AB

HIGH-PRESSURE
FUEL HOSE

AKX01457AB

FUEL PRESSURE
GAUGE

O-RING OR GASKET

MD998709

MD998742

HIGH-PRESSURE
FUEL HOSE

FUEL
RAIL

AKX01458

MB991637

O-RING OR GASKET

MD998709

MD998742

HIGH-
PRESSURE
FUEL HOSE

FUEL
RAIL

AB

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-523

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
4. Connect scan tool MB991502 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 270 kPa (38 psi) at
curb idle

9. Disconnect the vacuum hose (blue stripe) from the fuel

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

Standard value: 330

−−−−

350 kPa (47

−−−−

50 psi) at curb idle

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

after the engine has been revved several times.

11.Revving the engine repeatedly, hold the fuel return hose

lightly with your 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.

12.If any of fuel pressure measured in steps 8 to 11 is out of

specification, troubleshoot and repair according to the table
below.

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.

SYMPTOM

PROBABLE CAUSE

REMEDY

•

Fuel pressure too low

•

Fuel pressure drops after racing

•

No fuel pressure in fuel return
hose

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

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

Defective fuel pressure regulator

Replace fuel pressure regulator

AC003081 AB

16 PIN

MB991502

AK000119

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-524

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

P.13B-524

.)

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, MD998742 and MB991637 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 N

⋅⋅⋅⋅

m (43

±±±±

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 PUMP CONNECTOR
DISCONNECTION(HOW TO REDUCE
PRESSURIZED FUEL LINES)

M1131000900116

Refer to GROUP 13A, On-vehicle Service

−

Fuel Pump Relay

Disconnection (How to Reduce Pressurized Fuel Lines)

P.13A-

442

.

FUEL PUMP OPERATION CHECK

M1131002000108

Refer to GROUP 13A, On-vehicle Service

−

Fuel Pump

Operation Check

P.13A-442

.

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

M1131009900094

Refer to GROUP 13A, On-vehicle Service

−

Multiport Fuel

Injection (MFI) Relay and Fuel Pump Relay Continuity Check
(

P.13A-443

).

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