Mitsubishi Montero (2004+). Manual — part 374

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-983

Standard Wave Pattern

Wave Pattern Observation Points
Point: Condition of wave pattern build-up section and maximum

voltage (Refer to abnormal wave pattern examples 1 and 2.

.

Observation condition

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Approximately 1,200 r/min

CONDITION OF WAVE
PATTERN BUILD-UP
SECTION AND MAXIMUM
VOLTAGE

PROBABLE CAUSE

Rises from approximate 2
volts to approximate 4.5 volts
at the top-right

Normal

2-volt rectangular wave

Open-circuit in ignition primary
circuit

Rectangular wave at power
voltage

Ignition power transistor
malfunction

(V)

6

4

2

0

6

4

2

0

AK201316

75˚BTDC

5˚BTDC

ON

TIME

T

AB

θ

T1

OFF

CRANKSHAFT
POSITION
SENSOR OUTPUT
WAVE PATTERN

IGNITION POWER
TRANSISTOR
CONTROL SIGNAL
WAVE PATTERN

Standard wave pattern

T: REVOLUTION TIME CORRESPONDING

TO A CRANK ANGLE OF 180˚
COMPRESSION TOP DEAD CENTER

θ: SPARK

ADVANCE
ANGLE

IGNITION PERIOD

DWELL
SECTION

T1: TIME COMPUTED BY THE PCM

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-984

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 volts too low.

Example 2 (Wave pattern during engine cranking)

• Cause of problem

Malfunction in ignition power transister

• Wave pattern characteristics

Power voltage results when the ignition power transistor is
ON.

AKX01612

NORMAL WAVE
PATTERN

2V

AB

AKX01613

BATTERY
POSITION
VOLTAGE

NORMAL WAVE
PATTERN

AB

SPECIAL TOOLS

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MULTIPORT FUEL INJECTION (MFI)

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SPECIAL TOOLS

M1131000600591

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991958
A: MB991824
B: MB991827
C: MB991910
D: MB991911
E: MB991914
F: MB991825
G: MB991826
MUT-III sub assembly
A: Vehicle
Communication Interface
(V.C.I.)
B: MUT-III USB Cable
C: MUT-III Main Harness
A (Vehicles with CAN
communication system)
D: MUT-III Main Harness
B (Vehicles without CAN
communication system)
E: MUT-III Main Harness
C (for Daimler Chrysler
models only)
F: MUT-III Adapter
Harness
G: MUT-III Trigger
Harness

MB991824-KIT
NOTE: G: MB991826
MUT-III Trigger Harness
is not necessary when
pushing V.C.I. ENTER
key.

• Reading diagnostic

trouble code

• MFl system inspection

• Measurement of fuel

pressure

CAUTION

For vehicles with CAN
communication, use
MUT-III main harness A
to send simulated
vehicle speed. If you
connect MUT-III main
harness B instead, the
CAN communication
does not function
correctly.

MB991658
Test harness set

Tool not available

• Inspection using an

oscilloscope

• Adjustment of

accelerator pedal
position sensor

• Inspection of throttle

position sensor

MB991910

MB991826

MB991958

MB991911

MB991914

MB991824

MB991827

MB991825

DO NOT USE

A

B

C

D

E

F

G

DO NOT USE

MB991658

SPECIAL TOOLS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

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MB991709
Test harness set

MB991709-01

Inspection using an
oscilloscope

MD998474
Test harness (8 pin,
square)

MD998474-01

Inspection using an
oscilloscope

MD998464
Test harness (4 pin,
square)

MD998464-01

Inspection of heated
oxygen sensor

MB991316
Test harness (4 pin,
square)

Tool not available

Inspection of heated
oxygen sensor

MD998478
Test harness (3 pin,
triangle)

MD998478-01

Inspection using an
oscilloscope

MB991637
Fuel pressure gauge set

Tool not available

Measurement of fuel
pressure

MD998709
Adaptor hose

MIT210196

Measurement of fuel
pressure

MD998742
Hose adaptor

MD998742-01

Measurement of fuel
pressure

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991637