Mitsubishi Lancer Evolution X. Manual - part 447

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-853

Alternate method 

1. Disconnect all ECM connectors. Connect the check harness 

special tool (MB992110) between the separated connectors.

2. Connect the oscilloscope to check harness terminal No. 7. 

(Check the exhaust camshaft position sensor signal wave 
pattern.)

3. Connect the oscilloscope to check harness terminal No. 8. 

(Check the crankshaft position sensor signal wave pattern.)

Standard Wave Pattern

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AK604467AB

Power plant ECU
check harness connector

MB992110

AK704384

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Oscilloscope

Power plant ECU
check harness
connector

AB

Observation condition

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Idle speed

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-854

Wave Pattern Observation Points

• Verify that, toward the engine speed of 2,500 r/min, time dif-

ference T from when the crankshaft position sensor output 
wave falls to when the exhaust camshaft position sensor 
output wave falls becomes less.

.

Examples of Abnormal Wave Patterns

Example 1
Cause of problem

• Sensor interface malfunction.

Wave pattern characteristics

• Rectangular wave pattern is output even when the 

engine is not started.

Example 2
Cause of problem

• Loose timing belt.
• Abnormality in sensor disc.

Wave pattern characteristics

• Wave pattern is displaced to the left or right.

AK703482

(at advance angle) (at retard angle)

T

AE

(Volt)

5

0

5

0

(ms)

Phase angle

2 engine revolutions (1 camshaft revolution)

Standard wave pattern

Crankshaft position
sensor output wave
pattern

Exhaust camshaft
position sensor
output wave pattern

AK604469 AB

AK604470

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-855

INJECTOR

Required Special Tools:

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

.

Measurement Method

1. Disconnect the injector connector, and connect the test har-

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

2. Connect the oscilloscope probe to injector connector termi-

nal 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. 2 for the number 1 cylinder.
• Terminal No. 3 for the number 2 cylinder.
• Terminal No. 18 for the number 3 cylinder.
• Terminal No. 19 for the number 4 cylinder.

AK604471

1 2

AB

Injector
connector

MB991658

Oscilloscope

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AK604467AB

Power plant ECU
check harness connector

MB992110

AK704386

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2

1

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AB

Oscilloscope

Power plant ECU
check harness
connector

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-856

Standard Wave Pattern

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.

Observation conditions

Function

Special pattern

Pattern height

Variable

Variable knob

Adjust while viewing the 
wave pattern

Pattern selector

Display

Engine r/min

Idle speed

CONTRAST WITH 
STANDARD WAVE 
PATTERN

PROBABLE CAUSE

Injector coil induced voltage is 
low or doesn't appear at all

Short in the injector solenoid

AK703483

(Volt)

50

0

Standard wave pattern

Time

AD

Point A

Power voltage

Drive signal: ON

Drive signal: OFF

Solenoid back
electromotive force

Point B
Injector drive time

AK604472AB

When idling

When racing