Mitsubishi Lancer Evolution X. Manual - part 448

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-857

IGNITION COIL AND IGNITION POWER 
TRANSISTOR

Required Special Tools:

• MB991658: Test Harness
• MB992110: Power Plant ECU Check Harness

.

Measurement Method

1. Disconnect the ignition coil connector, and connect test har-

ness special tool (MB991658) between the separated con-
nector. (All terminals should be connected.)

2. Connect the oscilloscope probe to ignition coil connector 

terminal No. 2.

.

Alternate method 

1. Disconnect all ECM connectors. Connect the check har-

ness special tool (MB992110) between the separated con-
nectors.

2. Connect the oscilloscope probe to each check harness con-

nector terminal to analyze each cylinder:

• Terminal No. 4 for the number 1 cylinder.
• Terminal No. 5 for the number 2 cylinder.
• Terminal No. 20 for the number 3 cylinder.
• Terminal No. 21 for the number 4 cylinder.

AK704387

3 4

2

1

AB

Ignition coil
connector

Oscilloscope

MB991658

16 15 14 13 12 11 10 9 8 7 6 5 4 3

2

1

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

AK604467AB

Power plant ECU
check harness connector

MB992110

AK704388

16 15 14 13 12 11 10 9 8 7 6 5 4 3

2

1

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

AB

Oscilloscope

Power plant ECU
check harness
connector

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-858

Standard Wave Pattern

Wave Pattern Observation Points
Point: The power transistor control signal (ignition timing) is 

advanced when the engine speed is increased.

.

Observation condition

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Idle speed

CONDITION OF WAVE 
PATTERN BUILD-UP 
SECTION AND MAXIMUM 
VOLTAGE

PROBABLE CAUSE

Voltage value is too low

Open-circuit in ignition primary 
circuit

AK604736AB

0

5

OFF

ON

(ms)

Ignition period

Dwell section

Crankshaft position
sensor output wave
pattern

Power transistor
control signal
wave pattern

(Volt)

TDC

0

5

2 engine revolutions (1 camshaft revolution)

Standard wave pattern

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI)

13A-859

Examples of Abnormal Wave Patterns

Example 1 (Wave pattern during engine cranking)

• Cause of problem

Open-circuit in ignition primary circuit

• Wave pattern characteristics

Voltage value is too low.

ON-VEHICLE SERVICE

COMPONENT LOCATION

M1131002102929

AK604478

AB

Normal wave
pattern

NAME

SYMBOL

NAME

SYMBOL

Accelerator pedal position sensor V

Heated oxygen sensor (rear)

X

A/C compressor clutch relay

Q

Ignition coil

D

Clutch pedal position switch 
<M/T>

T

Injector

C

Crankshaft position sensor

O

Injector relay

Q

Data link connector

U

Intake air temperature sensor 2

L

Engine control module

P

Intake camshaft position sensor

L

Engine coolant temperature 
sensor

F

Intake engine oil control valve

A

ETACS-ECU (incorporating fuel 
pump relay 2)

S

Knock sensor

M

Evaporative emission purge 
solenoid

N

Malfunction Indicator Lamp (SERVICE 
ENGINE SOON or Check Engine Lamp)

R

Evaporative emission ventilation 
solenoid

Z

Manifold absolute pressure sensor

K

Exhaust camshaft position sensor E

Mass airflow sensor (incorporating intake 
air temperature sensor 1)

H

Exhaust engine oil control valve

B

MFI relay

Q

Fuel level sensor (sub)

W

Power steering pressure switch

J

Fuel pump circuit resistor

I

Starter relay

Q

Fuel pump module (incorporating 
fuel level sensor (main) and fuel 
tank temperature sensor)

Y

Throttle actuator control motor relay

Q

Fuel pump relay 1

Q

Throttle body assembly (incorporating 
throttle actuator control motor and throttle 
position sensor)

L

Fuel tank differential pressure 
sensor

Y

Turbocharger wastegate solenoid 1

G

Heated oxygen sensor (front)

X

Turbocharger wastegate solenoid 2

G

ON-VEHICLE SERVICE

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MULTIPORT FUEL INJECTION (MFI)

13A-860

AK704051

AC703980

A

D

B

J

K

L

I

C

P

E

F

G

H

N

O

Q

M

X

Y

W

Z

R

V

T

U

S

AB

AK704052

AB

A

Intake engine
oil control valve

Power steering
oil pump

AK704053

B

AB

Exhaust engine
oil control valve