Mitsubishi Galant 9G. Manual — part 917
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-1110
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.
EGR VALVE (STEPPER MOTOR)
Required Special Tools:
• MB991658: Test Harness
• MB991923: Power Plant ECU Check Harness
.
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) <2.4L ENGINE>
13A-1111
Measurement Method
1. Disconnect the EGR valve connector, and connect the test
harness special tool (MB991658) between the separated
connector (All terminals should be connected).
2. Connect the oscilloscope probe to the EGR valve connector
terminal No. 1, terminal No. 3, terminal No. 4, terminal No. 6
respectively.
.
Alternate method (Measure at the PCM)
1. Disconnect the all PCM connectors, and connect check
harness special tool (MB991923) between the separated
connectors.
2. Connect the oscilloscope probe to check harness terminal
No. 124, No. 130, No. 136 and No. 142.
Standard Wave Pattern
AK203303
1
2 3
4
5 6
EGR VALVE
CONNECTOR
OSCILLOSCOPE
MB991658
AB
Observation condition
Function
Special pattern
Pattern height
High
Pattern selector
Display
Engine condition
Revving
AK202954
127 126 125 124 123 122 121
133 132 131 130 129 128
140 139 138 137 136 135 134
146 145 144 143 142 141
153 152 151 150 149 148 147
AB
POWER PLANT ECU
CHECK HARNESS CONNECTOR
MB991923
PCM
AK203304
127 126 125 124 123 122 121
133 132 131 130 129 128
140 139 138 137 136 135 134
146 145 144 143 142 141
153 152 151 150 149 148 147
AB
OSCILLOSCOPE
POWER PLANT ECU
CHECK HARNESS
CONNECTOR
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <2.4L ENGINE>
13A-1112
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.)
Point B: Height of coil back electromotive force
.
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Induced electromotive force
does not appear or is
extremely small
Malfunction of motor
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Coil reverse electromotive
force does not appear or is
extremely small
Short in the coil
AKX01607 AC
(V)
30
20
10
0
EGR VALVE
(STEPPER
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) <2.4L ENGINE>
13A-1113
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 Tools:
• MB991658: Test Harness
• MB991923: Power Plant ECU Check Harness
.
Measurement Method
1. Disconnect the intermediate connector B-32, and connect
the test harness special tool (MB991658) between the sep-
arated connector.
2. Connect the oscilloscope probe to each intermediate con-
nector B-32 terminal to analyze each cylinder:
• Terminal No. 2 for the number 1 cylinder.
• Terminal No. 7 for the number 3 cylinder.
• Terminal No. 6 for the number 5 cylinder.
<Measure at the left bank (number 2, 4, 6 cylinders)>
1. Disconnect the ignition coil connector, and connect test har-
ness special tool (MB991348) between the separated con-
nector. (All terminals should be connected.)
2. Connect the oscilloscope probe to ignition coil connector
terminal No. 3.
.
AKX01608 AB
AKX01609
OPEN
CIRCUIT
SIDE
NORMAL
SIDE
AB
AK401067
1 2 3
IGNITION COIL
CONNECTOR
OSCILLOSCOPE
MB991658
AB
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