Mitsubishi Colt Ralliart. Manual — part 99
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI) <4A9>
13A-350
INJECTOR
Measurement Method
1. Disconnect the injector connector, and then
connect the special tool Test harness set
(MB991658) in between (All terminals should be
connected).
2. Connect the oscilloscope special patterns pickup
to terminal No. 2 of the injector connector.
Alternate Method (Test harness not
available)
1. Disconnect the engine-ECU connector or
engine-CVT-ECU connector and connect the
special tool Power plant ECU check harness
(MB991987) in between.
2. Connect the oscilloscope special patterns pickup
to engine-ECU <M/T> or engine-CVT-ECU
<CVT> terminal No. 8 (When checking the No. 1
cylinder).
3. Connect the oscilloscope special patterns pickup
to engine-ECU <M/T> or engine-CVT-ECU
<CVT> terminal No. 9 (When checking the No. 2
cylinder).
4. Connect the oscilloscope special patterns pickup
to engine-ECU <M/T> or engine-CVT-ECU
<CVT> terminal No. 23 (When checking the No. 3
cylinder).
5. Connect the oscilloscope special patterns pickup
to engine-ECU <M/T> or engine-CVT-ECU
<CVT> terminal No. 24 (When checking the No. 4
cylinder).
Standard Wave Pattern
Observation conditions
AK101807
1
2
AC
Special
patterns
pickup
Oscilloscope
Function
Special patterns
Pattern height
Variable
Variable knob
Adjust while viewing the
wave pattern
Pattern selector
Display
Engine
Idle
AK305803
(V)
50
0
Power
voltage
Solenoid back
electromotive force
(Approximately 7×10V)
Drive signal: ON
Drive signal: OFF
Point B
Injector drive
time
Point A.
Standard wave pattern
Time
AB
Main
Index
Group
TOC
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI) <4A9>
13A-351
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
M.U.T.-III 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.
IGNITION COIL AND POWER TRANSIS-
TOR
Measurement Method
1. Disconnect the ignition coil connector, and
connect the special tool Test harness (MB991658)
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. Disconnect the engine-ECU connector or
engine-CVT-ECU connector and connect the
special tool Power plant ECU check harness
(MB991987) in between.
2. Connect the oscilloscope probe to engine-ECU
<M/T> or engine-CVT-ECU <CVT> terminal No.
10. (When checking the No. 1 cylinder.)
3. Connect the oscilloscope probe to engine-ECU
<M/T> or engine-CVT-ECU <CVT> terminal No.
25. (When checking the No. 2 cylinder.)
4. Connect the oscilloscope probe to engine-ECU
<M/T> or engine-CVT-ECU <CVT> terminal No.
40. (When checking the No. 3 cylinder.)
5. Connect the oscilloscope probe to engine-ECU
<M/T> or engine-CVT-ECU <CVT> terminal No.
55. (When checking the No. 4 cylinder.)
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
AK300345
1 2 3
AB
Special
patterns
pickup
Oscilloscope
Main
Index
Group
TOC
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI) <4A9>
13A-352
Standard Wave Pattern
Observation condition
Wave Pattern Observation Points
Point: When the engine speed increases, verify that
the power transistor control signal (ignition timing)
advances.
Examples of Abnormal Wave Patterns
•
Example
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.
Function
Special patterns
Pattern height
Low
Pattern selector
Display
Engine
Idle
AK204112
Standard wave pattern
Crank angle
sensor output
wave pattern
Power transistor
control signal
wave pattern
TDC: Top dead centre
AC
2 engine revolutions
(1 camshaft revolution)
Ignition timing
Dwell section
0
10
OFF
ON
5˚ BTDC
(V)
TDC
0
5
AK203246
Normal wave pattern
AD
Main
Index
Group
TOC
TROUBLESHOOTING
MULTIPORT FUEL INJECTION (MPI) <4A9>
13A-353
EGR VALVE (STEPPER MOTOR) <CVT>
Measurement Method
1. Disconnect the EGR valve connector, and con-
nect the special tool test harness (MB991658) in
between.
2. Connect the oscilloscope probe to the EGR
valve-side connector terminal 1, terminal 3, termi-
nal 4 and terminal 6 respectively.
Alternate Method (Test Harness not
Available)
1. Disconnect the engine-CVT-ECU connector and
connect the special tool Power plant ECU check
harness (MB991987) in between.
2. Connect the oscilloscope probe to
engine-CVT-ECU terminal No. 5, connection
terminal No. 6, connection terminal No. 53, and
connection terminal No. 54 respectively.
Standard Wave Pattern
Observation condition
Wave pattern Observation Points
Check that the standard wave pattern appears when
the EGR control servo 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
AK303311
1 2 3
4 5 6
AB
Special
patterns
pickup
Oscilloscope
Function
Special patterns
Pattern height
High
Pattern selector
Display
Engine
Ignition switch: OFF
→
ON
AK301251
0
0
Standard wave pattern
Stepper motor
control signal
wave pattern
Stepper motor
control signal
wave pattern
Motor coil energizing time
Point A
Induced electromotive
force from the motor
turning
Point B
Coil reverse electromotive
force (Approximately 40 V)
AE
(V)
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
Main
Index
Group
TOC
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