2007 MITSUBISHI LANCER EVOLUTION Service Repair Manual

MPI -Troubleshooting13A-117
Examples of Abnormal Wave Patterns
DExample 1
Cause of problem
Sensor interface malfunction
Wave pattern characteristics
Rectangular wave pattern is output even when the engine
is not started.
DExample 2
Cause of problem
Damaged rectifier or vortex generation column
Wave pattern characteristics
Unstable wave pattern with non-uniform frequency.
However, when an ignition leak occurs during acceleration,
the wave pattern will be distorted temporarily, even if the air
flow sensor is normal.
CAMSHAFT POSITION SENSOR AND CRANK ANGLE
SENSOR
Measurement Method
1. Disconnect the camshaft position sensor connector and
connect the special tool (test harness: MB991709) in
between. (All terminals should be connected.)
2. Connect the analyzer special patterns pickup to camshaft
position sensor terminal No. 2.
3. Disconnect the crank angle sensor connector and connect
the special tool (test harness: MD998478) in between.
4. Connect the analyzer special patterns pickup to crank
angle sensor terminal No. 2.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 88. (When checking the
camshaft position sensor signal wave pattern.)
2. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 89. (When checking the crank
angle sensor signal wave pattern.)
Crank angle
sensor connector
Camshaft position sensor
connectorAnalyzer
Special patterns
pick-up

MPI -Troubleshooting13A-118
Standard Wave Pattern
Observation condition
FunctionSpecial patterns
Pattern heightLow
Pattern selectorDisplay
Engine r/minIdle speed
Standard Wave Pattern
Crank angle
sensor output
wave pattern(V)
75_BTDC2 engine revolutions
(1 camshaft revolution)
5_BTDCThe time (cycle time) T is
reduced when the engine
speed increases
0
Camshaft position
sensor output
wave pattern
TDC: Top dead centre131_49_
No. 1 TDC No. 3 TDC No. 4 TDC No. 2 TDCTime
056_34_
Wave Pattern Observation Points
Check that cycle time T becomes shorter when the engine speed increases.
Examples of Abnormal Wave Patterns
DExample 1
Cause of problem
Sensor interface malfunction
Wave pattern characteristics
Rectangular wave pattern is output even when the engine
is not started.

MPI -Troubleshooting13A-119
DExample 2
Cause of problem
Loose timing belt
Abnormality in sensor disk
Wave pattern characteristics
Wave pattern is displaced to the left or right.
INJECTOR
Measurement Method
1. Disconnect the injector connector, and then connect the
special tool (test harness: MB991348) in between.
(All terminals should be connected.)
2. Connect the analyzer special patterns pickup to terminal
No. 2 of the injector connector.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 1. (When checking the No. 1
cylinder.)
2. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 14. (When checking the No.
2 cylinder.)
3. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 2. (When checking the No. 3
cylinder.)
4. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 15. (When checking the No.
4 cylinder.)
Standard Wave Pattern
Observation conditions
FunctionSpecial patterns
Pattern heightVariable
Variable knobAdjust while viewing the wave pattern
Pattern selectorDisplay
Engine r/minIdle speed
Special
patterns
pickupAnalyzer

MPI -Troubleshooting13A-120
Standard wave pattern
(V)
Point A
Point BSolenoid back electromotive force
(Approx. 7×10 V)
Injector drive time
Power voltage
Drive signal: ON Drive signal: OFF
Time 50
0
Wave Pattern Observation Points
Point A: Height of solenoid back electromotive force
Contrast with standard wave patternProbable cause
Solenoid coil back electromotive force is low or doesn’t
appear at all.Short in the injector solenoid
Point B: Injector drive time
DThe injector drive time will be synchronized with the MUT-II
tester display.
DWhen the engine is suddenly raced, the drive time will
be greatly extended at first, but the drive time will soon
match the engine speed.
When idling
When racing ---
--

MPI -Troubleshooting13A-121
IDLE SPEED CONTROL SERVO (STEPPER MOTOR)
Measurement Method
1. Disconnect the idle speed control servo connector, and
connect the special tool (test harness: MB991709) in
between.
2. Connect the analyzer special patterns pickup to the idle
speed control servo-side connector terminal No. 1,
terminal No. 3, terminal No. 4 and terminal No. 6
respectively.
Alternate Method (Test harness not available)
1. Connect the analyzer 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
FunctionSpecial patterns
Pattern heightHigh
Pattern selectorDisplay
Engine conditionWhen the engine coolant temperature is 20_C or below, turn the ignition switch from “LOCK”
(OFF) position to “ON” position (without starting the engine).
While the engine is idling, turn the A/C switch to ON.
Immediately after starting the warm engine
Standard wave pattern
Stepper
motor
control
signal
wave
pattern(V)
30
20
10The wave pattern
appears for an
instant, but soon
disappears.Point B
Coil reverse electromotive
force (Approx. 3×10 V)Point A
Induced electromotive force
from the motor turning
Time
Special
patterns
pickupAnalyzer

MPI -Troubleshooting13A-122
Wave Pattern Observation Points
Check that the standard wave pattern appears when the stepper motor is operating.
Point A: Presence or absence of induced electromotive force from the motor turning. (Refer to the abnormal
wave pattern.)
Contrast with standard wave patternProbable cause
Induced electromotive force does not appear or is extremely small.Motor is malfunctioning
Point B: Height of coil reverse electromotive force
Contrast with standard wave patternProbable cause
Coil reverse electromotive force does not appear or is extremely small.Short in the coil
Examples of Abnormal Wave Pattern
DExample 1
Cause of problem
Motor is malfunctioning. (Motor is not operating.)
Wave pattern characteristics
Induced electromotive force from the motor turning does
not appear.
DExample 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 different from the normal
waveform.
Open
circuit
side
Normal
side

MPI -Troubleshooting13A-123
IGNITION COIL AND POWER TRANSISTOR
DIgnition coil primary signal
Refer to GROUP 16 - Ignition system.
DPower transistor control signal
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 analyzer special patterns pickup to terminal
No. 3 of each ignition coil connector in turn.
Alternate Method (Test harness not available)
1. Connect the analyzer special patterns pickup to
engine-ECU terminal No. 10 (No. 1 - No. 4), terminal
No. 23 (No. 2 - No. 3) respectively.
Standard Wave Pattern
Observation condition
FunctionSpecial patterns
Pattern heightLow
Pattern selectorDisplay
Engine r/minApproximately 1,200 r/min
Standard wave pattern
Crank angle
sensor output
wave pattern
Power transistor
control signal
wave pattern(V)
75_BTDC5_BTDCT: Revolution time corresponding to a crank angle of 180_
Compression top dead center
θ: Spark
advance
angleIgnition period
OFF ON
Dwell section
T1: Time computed by the engine-ECUTime θ T1T
6
4
2
0
4
2
0
Special
patterns
pickupAnalyzer

MPI -Troubleshooting13A-124
Wave Pattern Observation Points
Point: Condition of wave pattern build-up section and maximum voltage (Refer to abnormal wave pattern
examples 1 and 2.)
Condition of wave pattern build-up section and maximum voltageProbable cause
Rises from approximately 2 V to approximately 4.5 V at the
top-rightNormal
2 V rectangular waveOpen-circuit in ignition primary circuit
Rectangular wave at power voltagePower transistor malfunction
Examples of Abnormal Wave Patterns
DExample 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.
DExample 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.--- Normal wave pattern
2V
VB
--- Normal wave pattern