Mitsubishi Montero (2004+). Manual — part 373
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-979
INJECTOR
Required Special Tool:
• MD998474: Test Harness
.
Measurement Method
1. Disconnect the injector intermediate connector, and connect
the test harness special tool (MD998474) in between.
2. Connect the oscilloscope probe to each injector
intermediate connector terminal to analyze each cylinder:
• Terminal No. 3 (green clip of special tool) for the number 1
cylinder
• Terminal No. 2 (white clip) for the number 2 cylinder
• Terminal No. 1 (blue clip) for the number 3 cylinder
• Terminal No. 7 (yellow clip) for the number 4 cylinder
• Terminal No. 6 (red clip) for the number 5 cylinder
• Terminal No. 5 (black clip) for the number 6 cylinder
.
Alternate method (Test harness not available)
1. Connect the oscilloscope probe to PCM terminal No. 1.
(When checking the number 1 cylinder.)
2. Connect the oscilloscope probe to PCM terminalNo. 5.
(When checking the number 2 cylinder.)
3. Connect the oscilloscope probe to PCM terminal No. 14.
(When checking the number 3 cylinder.)
4. Connect the oscilloscope probe to PCM terminal No. 21.
(When checking the number 4 cylinder.)
5. Connect the oscilloscope probe to PCM terminal No. 2.
(When checking the number 5 cylinder.)
6. Connect the oscilloscope probe to PCM terminal No. 6.
(When checking the number 6 cylinder.)
Standard Wave Pattern
Observation conditions
Function
Special pattern
Pattern height
Variable
Variable knob
Adjust while viewing the
wave pattern
Pattern selector
Display
Engine r/min
Idle speed
AK102982 AB
OSCILLOSCOPE
INJECTOR
INTERMEDIATE
CONNECTOR
MD998474
1 2 3 4
5 6 7 8
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-980
Wave Pattern Observation Points
Point A: Height of injector coil induced voltage.
Point B: Injector drive time
1. The injector drive time should be synchronized with the
scan tool tester display.
2. When the engine is suddenly revved, the drive time will
be greatly extended at first, but the drive time will soon
return to original length.
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Injector coil induced voltage is
low or doesn't appear at all
Short in the injector solenoid
AKX01604
(V)
50
0
DRIVE SIGNAL:"ON"
POINT B:
INJECTOR DRIVE
TIME
POINT A
DRIVE SIGNAL:"OFF"
POWER VOLTAGE
INJECTION COIL INDUCED
VOLTAGE (APPROXIMATELY 50-60 V)
AB
Standard wave pattern
AKX01605
WHEN IDLING
WHEN RACING
AB
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-981
EGR VALVE (STEPPER MOTOR)
Required Special Tool:
• MB991658: Test Harness
.
Measurement Method
1. Disconnect the EGR valve connector, and connect the test
harness special tool (MB991658) in between. (All terminals
should be connected.)
2. Connect the oscilloscope probe to the EGR valve connector
terminal No. 1, terminal No. 3, terminal No. 4, No. terminal 6
respectively.
.
Alternate method (Test harness not available)
1. Connect the oscilloscope probe to PCM terminals No. 3, No.
12, No. 19 and No. 26.
Standard Wave Pattern
Wave Pattern Observation Points
1. Check that the standard wave pattern appears when the
EGR valve is operating.
Point A: Presence or absence of induced electromotive force
from the motor turning. (Refer to abnormal wave pattern.)
Observation condition
Function
Special pattern
Pattern height
High
Pattern selector
Display
Engine condition
Racing
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Induced electromotive force
does not appear or is
extremely small
Malfunction of motor
AK201315
1 2 3
4 5 6
EGR VALVE
CONNECTOR
OSCILLOSCOPE
MB991658
AB
AKX01607 AB
(V)
30
20
10
0
IAC
MOTOR
CONTROL
SIGNAL
WAVE
PATTERN
THE WAVE PATTERN
APPEARS FOR AN
INSTANT, BUT SOON
DISAPPEARS.
POINT B COIL RE-
VERSE ELECTRO-
MOTIVE FORCE
(APPROXIMATELY
3 x10 V)
POINT AN INDUCED
ELECTROMOTIVE
FORCE FROM THE
MOTOR TURNING
TIME
Standard wave pattern
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI)
13A-982
Point B: Height of coil back electromotive force
.
Examples of Abnormal Wave Patterns
Example 1
Cause of problem
• Malfunction of motor. (Motor is not operating.)
Wave pattern characteristics
• Induced electromotive force from the motor turning does
not appear.
Example 2
Cause of problem
• Open circuit in the line between the EGR valve and the
PCM.
Wave pattern characteristics
• Current is not supplied to the motor coil on the open cir-
cuit side. (Voltage does not drop to 0 volt.) Furthermore,
the induced electromotive force wave pattern at the nor-
mal side is slightly different from the normal wave pat-
tern.
IGNITION COIL AND IGNITION POWER
TRANSISTOR
Required Special Tool:
• MB991658: Test Harness Set
.
Measurement Method
1. Disconnect the ignition coil connector, and connect test
harness special tool, MB991658, in between. (All terminals
should be connected.)
2. Connect the oscilloscope probe to ignition coil connector
terminal No. 3.
.
Alternate method (Test harness not available)
Connect the oscilloscope probe to PCM terminals No. 31 (for
number 1
− number 4), terminal No. 35 (for number 2 −
number 5) , terminal No. 44 (for number 3
− number 6)
respectively.
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Coil reverse electromotive
force does not appear or is
extremely small
Short in the coil
AKX01608 AB
AKX01609
OPEN
CIRCUIT
SIDE
NORMAL
SIDE
AB
1
2
3
AK303226
IGNITION COIL
CONNECTOR
AK303226AB
MB996548
OSCILLOSCOPE
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