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Mitsubishi Outlander (2003+). Manual - part 110

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-303

Wave Pattern Observation Points
Point A: Height of solenoid back electromotive force

Point B: Injector drive time

The injector drive time will be synchronized with the

MUT-II tester display.

When the engine is suddenly raced, the drive
time will be greatly extended at first, but the drive
time will soon match the engine speed.

IDLE SPEED CONTROL (ISC) SERVO
(STEPPER MOTOR)

Measurement Method

1. Disconnect the ISC servo connector, and connect

the special tool Test harness (MB991709) in
between.

2. Connect the oscilloscope special patterns pickup

to the ISC servo-side connector terminal No. 1,
No. 3, No. 4 and No. 6 respectively.

Alternate Method (Test harness not available)
1. Connect the oscilloscope special patterns pickup

to engine-ECU terminal No. 4, connection
terminal No. 5, connection terminal No. 17, and
connection terminal No. 18 respectively.

Standard Wave Pattern

Observation conditions

Contrast with standard wave
pattern

Probable
cause

Solenoid coil back electromotive
force is low or doesn’t appear at
all.

Short in the
injector solenoid

AKX01605AE

When idling
When racing

1 2 3

AK300344AB

Special
patterns
pickup

Oscilloscope

Function

Special patterns

Pattern height

High

Pattern selector

Display

Engine condition

When the engine coolant
temperature is 20

C or

below, turn the ignition
switch from LOCK (OFF)
position to ON (without
starting the engine).

While the engine is
idling, turn the A/C
switch to ON.

Immediately after
starting the warm
engine.

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-304

Wave pattern Observation Points
Check that the standard wave pattern appears when
the stepper motor is operating.
Point A: Presence or absence of induced electromo-
tive force from the motor turning (Refer to the abnor-
mal wave pattern).

Point B: Height of coil reverse electromotive force

Examples of Abnormal Wave Pattern

Example 1

Cause of problem
Motor is malfunctioning. (Motor is not operating.)

Wave pattern characteristics
Induced electromotive force from the motor turn-

ing does not appear.

Example 2

Cause of problem
Open circuit in the line between the stepper

motor and the engine-ECU.

Wave pattern characteristics
Current is not supplied to the motor coil on the

open circuit side (Voltage does not drop to 0
V).

Furthermore, the induced electromotive force

waveform at the normal side is slightly differ-
ent from the normal waveform.

AK201857

(V)

Stepper
motor
control
signal
wave
pattern

The wave pattern
appears for an
instant, but soon
disappears.

Point B
Coilreverse electromotive
force (Approx.3x10V)

Standard wave pattern

Point A
Induced electromotive force
from the motor turning

Time

Contrast with standard wave
pattern

Probable
cause

Induced electromotive force does
not appear or is extremely small.

Motor is
malfunctioning

Contrast with standard wave
pattern

Probable
cause

Coil reverse electromotive force
does not appear or is extremely
small.

Short in the
coil

AKX01608AE

AKX01609AF

Open
circuit
side

Normal
side

TROUBLESHOOTING

MULTIPORT FUEL INJECTION (MFI)

13A-305

IGNITION COIL AND POWER TRANSIS-
TOR

Measurement Method

1. Disconnect the ignition coil connector, and

connect the special tool Test harness set
(MB991348) in between (All terminals should be
connected).

2. Connect the oscilloscope special patterns pickup

to terminal No. 3 of each ignition coil connector in
turn.

Alternate Method (Test harness not available)
1. Connect the oscilloscope special patterns pickup

to engine-ECU terminal No. 10 (No. 1

No. 4),

connection terminal No. 23 (No. 2

No.3)

respectively.

Standard Wave Pattern

Observation condition

Wave Pattern Observation Points
Point: Condition of wave pattern build-up section and
maximum voltage (Refer to abnormal wave pattern
examples 1 and 2).

AK300345

1 2 3

Special
patterns
pickup

Oscilloscope

Function

Special patterns

Pattern height

Low

Pattern selector

Display

Engine r/min

Approximately. 1,200
r/min

AK204435

(V)

Crank angle
sensor output
wave pattern

Power transistor
control signal
wave pattern

75˚ BTDC

5˚ BTDC

Compression top dead center

T1 : Time computed by the engine-ECU

T : Revolution time corresponding to a crank angle of 180˚

Ignition period

OFF

Dwell section

: Spark advance angle

Standard wave pattern

Condition of wave pattern
build-up section and
maximum voltage

Probable cause

Rises from approximately. 2 V
to approximately 4.5 V at the
top-right

Normal

2 V rectangular wave

Open-circuit in
ignition primary
circuit

Rectangular wave at power
voltage

Power transistor
malfunction

ON-VEHICLE SERVICE

MULTIPORT FUEL INJECTION (MFI)

13A-306

Examples of Abnormal Wave Patterns

Example 1
Wave pattern during engine cranking

Cause of problem
Open-circuit in ignition primary circuit

Wave pattern characteristics
Top-right part of the build-up section cannot be

seen, and voltage value is approximately 2 V
too low.

Example 2
Wave pattern during engine cranking

Cause of problem
Malfunction in power transistor

Wave pattern characteristics
Power voltage results when the power transistor

is ON.

ON-VEHICLE SERVICE

THROTTLE BODY (THROTTLE VALVE
AREA) CLEANING

M1131001000332

1. Remove the air intake hose from the throttle body.
2. Spray cleaning fluid on a clean cloth.

CAUTION

Do not spray the cleaning fluid directly to the
throttle valve.

Make sure the cleaning fluid does not enter
the motor from the bypass line. Also make
sure it does not enter the sensor through the
shaft.

Be careful not to rub off the molybden applied
around the throttle valve shaft.

3. Wipe off the dirt around the throttle valve with the

cloth sprayed with cleaning fluid.

4. Attach the air intake hose.

5. Adjust the basic idle speed (Refer to

13A

THROTTLE POSITION SENSOR
ADJUSTMENT

M1131001100414

1. Connect the MUT-II to the diagnosis connector.

When not using the MUT-II, proceed as follows.

AKX01612AD

Normal wave pattern

AKX01613AD

Normal wave pattern

AK000833AD

15 mm

Areas on throttle valve to
apply molybdenum disulfide

AK300346

2 3

Throttle position
sensor

Equipment side connector

AK201752AB

MB991536

Throttle position
sensor

Content .. 108 109 110 111 ..