Mitsubishi Galant. Manual — part 189

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-437

WARNING

Battery posts, terminals and related accessories
contain lead and lead compounds. WASH HANDS
AFTER HANDLING.

NOTE: If the engine hunts while idling after adjustment of
the basic idle speed, disconnect the negative cable from the
battery for 10 seconds or more, and then reconnect it and
run the engine at idle for about 10 minutes after the engine
is warmed up.

THROTTLE POSITION SENSOR ADJUSTMENT

M1131001100061

Required Special Tools:
MB991502: Scan Tool (MUT-II)
MB991348: Test Harness Set

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to the "LOCK" (OFF) position before
connecting or disconnecting the scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.

When not using scan tool follow the steps below.

(1) Disconnect the throttle position sensor connector, and

connector the special tool MB991348 in between. (All
terminals should be connected.)

(2) Connect a digital voltmeter between throttle position

sensor terminal 3 (sensor output) and terminal 1 (sensor
ground).

2. Turn the ignition switch to the "ON" position (but do not start

the engine).

3. Check the throttle position sensor output voltage.

Standard value: 535

−−−−

735 mV

AC003081 AB

16 PIN

MB991502

ACX02472

THROTTLE
POSITION
SENSOR

AD

AKX01636AB

TERMINAL 3
(SENSOR OUTPUT)

TERMINAL 1
(SENSOR
GROUND)

MB991348

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-438

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. When the scan tool is not

used, remove special tool MB991348, and connect the
throttle position sensor connector.

BASIC IDLE SPEED ADJUSTMENT

M1131001800082

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

NOTE: The standard idle speed has been adjusted with the
speed adjusting screw (SAS), by the manufacturer, and 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.

Standard value: 700

±±±±

50 r/min

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.

AK000113AB

AC003081 AB

16 PIN

MB991502

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

13A-439

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.13A-436

)

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

M1131001900078

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.13A-442

.)

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 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.

AK000114

AK000116AB

HIGH-PRESSURE FUEL HOSE

AKX01457AB

FUEL PRESSURE
GAUGE

O-RING OR GASKET

MD998709

MD998742

HIGH-PRESSURE
FUEL HOSE

FUEL
RAIL

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MULTIPORT FUEL INJECTION (MFI) <2.4L>

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<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) to

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.

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 the 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 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 10 to 13 is out of

specification, troubleshoot and repair according to the table
below.

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

AKX01458

MB991637

O-RING OR GASKET

MD998709

MD998742

HIGH-
PRESSURE
FUEL HOSE

FUEL
RAIL

AB

AC003081 AB

16 PIN

MB991502

AK000118