Mitsubishi Galant. Manual — part 322

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-513

Measurement Method
1. Disconnect the connector, and connect test harness special

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

2. Connect the oscilloscope probe to ignition coil connector

terminal 3.

Alternate method (Test harness not available)

1. Connect the oscilloscope probe to PCM terminal 11.

Standard Wave Pattern

Wave Pattern Observation Points
Point: Condition of wave pattern build-up section and maximum

voltage (Refer to abnormal wave pattern examples 1 and 2.

Observation conditions

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Approximately 1,200 r/min

AK000067

1 2 3 4 5 6 7

OSCILLOSCOPE

DISTRIBUTOR
CONNECTOR

OSCILLO

SCOPE

PLOBE

AB

AK000069

CRANKSHAFT

POSITION

SENSOR OUTPUT

WAVE PATTERN

(REFERENCE)

IGNITION POWER

TRANSISTOR

CONTROL SIGNAL

WAVE PATTERN

POINT:

WAVE BUILD-UP

SECTION

Standard wave pattern

θ

θ

: SPARK ADVANCE ANGLE

ON

DWELL SECTION

TIME

OFF

T

T : CRANKSHAFT ANGLE (120˚)

COMPRESSION
TOP DEAD CENTER

0

2

4

6

0

2

4

6

(V)

MULTIPORT FUEL INJECTION(MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-514

Examples of Abnormal Wave Patterns
Example 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 volts too low.

Example 2 (Wave pattern during engine cranking)

•

Cause of problem
Malfunction in ignition power transister

•

Wave pattern characteristics
Power voltage results when the ignition power transistor is
ON.

CONDITION OF WAVE
PATTERN BUILD-UP
SECTION AND MAXIMUM
VOLTAGE

PROBABLE CAUSE

Rises from approximate 2
volts to approximate 4.5 volts
at the top-right

Normal

2-volt rectangular wave

Open-circuit in ignition primary
circuit

Rectangular wave at power
voltage

Ignition power transistor
malfunction

AKX01612

NORMAL WAVE
PATTERN

2V

AB

AKX01613

BATTERY
POSITION
VOLTAGE

NORMAL WAVE
PATTERN

AB

SPECIAL TOOLS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-515

SPECIA L TO O LS

M1131000600096

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991502
Scan tool <MUT-II>

MB991496-OD

•

Reading diagnostic
trouble code

•

MFI system inspection

•

Measurement of fuel
pressure

MB991348
Test harness set

MB991348-01

•

Adjustment of throttle
position sensor

•

Inspection using an
oscilloscope

MB991709
Test harness set

MB991709-01

•

Inspection using an
oscilloscope

•

Inspection of idle air
control motor

MB991658
Test harness set

Tool not available

Inspection of heated
oxygen sensor

MD998464
Test harness (4 pin,
square)

MD998464-01

•

Inspection of heated
oxygen sensor

•

Inspection using an
oscilloscope

MB991316
Test harness (4 pin,
square)

Tool not available

•

Inspection of heated
oxygen sensor

MD998478
Test harness (3 pin,
triangle)

MD998478-01

Inspection using an
oscilloscope

B991502

MB991348

MB991658

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L>

13B-516

O N -VEH IC LE SERVIC E

COMPONENT LOCATION

M1131002100097

MD998709
Adaptor hose

MIT210196

Measurement of fuel
pressure

MD998742
Hose adaptor

MD998742-01

MB991637
Fuel pressure gauge set

Tool not available

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991637

NAME

SYMBOL

NAME

SYMBOL

Air conditioning compressor clutch
relay

J

Knock sensor

E

Crankshaft position sensor

KLeft bank heated oxygen sensor

(front)

N

Data link connector

T

Left bank heated oxygen sensor
(rear)

M

Distributor (built-in camshaft position
sensor and ignition coil)

I

Manifold differential pressure sensor D

EGR solenoid

A

Multiport fuel injection (MFI) relay/
fuel pump relay

J

Engine coolant temperature sensor

P

Park/neutral position switch

Q

Evaporative emission purge
solenoid

A

Powertrain control module

U

Evaporative emission ventilation
solenoid

R

Power steering pressure switch

L

Fan controller

O

Right bank heated oxygen sensor
(front)

B

Fuel tank differential pressure
sensor

W

Right bank heated oxygen sensor
(rear)

V