Mitsubishi Eclipse. Manual - part 636

 

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Mitsubishi Eclipse. Manual - part 636

 

 

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1087

Standard Wave Pattern

Wave Pattern Observation Points

1. Check that cycle time T becomes shorter and the frequency 

increases when the engine speed is increased.

.

Observation conditions

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Idle speed

Observation conditions

Rev engine, observe T1 and T2 remain equal.

AKX01595

THE TIME (CYCLE TIME) T IS REDUCED WHEN THE
AMOUNT OF INTAKE AIR INCREASES.

TIMES T

1

 AND T

2

 ARE EQUAL

T

T

1

T

2

10

0

(V)

TIME

AB

Standard wave pattern

AKX01596

10

0

(V)

T

TIME

AB

Standard wave pattern

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1088

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

Damaged rectifier or vortex generation column.

• Wave pattern characteristics

Unstable wave pattern with non-uniform frequency. An igni-
tion leak will distort the wave pattern temporarily, even if the 
volume airflow sensor is normal.

CAMSHAFT POSITION SENSOR AND 
CRANKSHAFT POSITION SENSOR

Required Special Tools:

• MB991348: Test Harness

• MD998478: Test Harness

.

Measurement Method
1. Disconnect the camshaft position sensor connector, and 

connect the test harness special tool (MB991348) in 
between. (All terminals should be connected.)

2. Connect the oscilloscope probe to camshaft position sensor 

connector terminal 5.

3. Disconnect the crankshaft position sensor connector, and 

connect the test harness special tool (MD998478) in 
between.

4. Connect the oscilloscope probe to crankshaft position 

sensor connector terminal 2 (black clip of special tool).

.

Alternate method (Test harness not available)

<M/T>

1. Connect the oscilloscope probe to ECM terminal 50. (Check 

the camshaft position sensor signal wave pattern.)

2. Connect the oscilloscope probe to ECM terminal 43. (Check 

the crankshaft position sensor signal wave pattern.)

<A/T>

1. Connect the oscilloscope probe to PCM terminal 56. (Check 

the camshaft position sensor signal wave pattern.)

2. Connect the oscilloscope probe to PCM terminal 45. (Check 

the crankshaft position sensor signal wave pattern.)

AKX01597

AK102977AB

1 2 3 4 5 6 7

CAMSHAFT POSITION
SENSOR CONNECTOR

OSCILLOSCOPE

MB991348

AK102979AB

MD998478

1 2

3

CRANKSHAFT POSITION
SENSOR CONNECTOR

OSCILLOSCOPE

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1089

Standard Wave Pattern

Wave Pattern Observation Points

1. Check that cycle time T becomes shorter when the engine 

speed increased.

.

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.

Observation conditions

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Idle speed

AKX01600

2 ENGINE REVOLUTIONS (1 CAMSHAFT REVOLUTION)

75

BTDC

5

BTDC

T

CYCLE TIME CHANGES
WITH ENGINE SPEED
CHANGES

CRANKSHAFT

POSITION

SENSOR OUTPUT

WAVE PATTERN

CAMSHAFT

POSITION

SENSOR OUTPUT

WAVE PATTERN

TDC: TOP DEAD CENTER

NO.1 TDC

NO.2 TDC

NO.3 TDC

NO.4 TDC

NO.5 TDC

NO.6 TDC

TIME

Standard wave pattern

AB

AKX01597

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-1090

Example 2

• Cause of problem

Loose timing belt.
Abnormality in sensor disc.

• Wave pattern characteristics

Wave pattern is displaced to the left or right.

INJECTOR

Required Special Tools:

• MB991348: Test Harness

• MD998464: Test Harness

.

Measurement Method
<Measure at the right bank (number 1, 3, 5 cylinders)>

1. Disconnect the injector intermediate connector, and connect 

the test harness special tool (MD998464) in between.

2. Connect the oscilloscope probe to each injector 

intermediate connector terminal to analyze each cylinder:

• Terminal 2 (black clip of special tool) for the number 1 cylin-

der

• Terminal 3 (blue clip) for the number 3 cylinder

• Terminal 4 (white clip) for the number 5 cylinder

<Measure at the right bank (number 2, 4, 6 cylinders)>

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

ness special tool (MB991348) in between. (All terminals 
should be connected.)

2. Connect the oscilloscope probe to injector connector termi-

nal 2.

Alternate method (Test harness not available)

1. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 1. (When checking the number 1 cylinder.)

2. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 9. (When checking the number 2 cylinder.)

3. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 24. (When checking the number 3 cylinder.)

4. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 2. (When checking the number 4 cylinder.)

5. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 10. (When checking the number 5 cylinder.)

6. Connect the oscilloscope probe to ECM <M/T> or PCM 

<A/T> terminal 25. (When checking the number 6 cylinder.)

AKX01602

AK102981

INJECTOR INTERMEDIATE
CONNECTOR

MD998464

OSCILLOSCOPE

AB


3 4

2

AK102980

1 2

INJECTOR
CONNECTOR

MB991348

AB

OSCILLOSCOPE

 

 

 

 

 

 

 

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