Mitsubishi 380. Manual — part 641

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI) <3.8L ENGINE>

13A-656

Point B: Injector drive time

1. The injector drive time should be synchronized with the

diagnostic tool 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.

IGNITION COIL AND IGNITION POWER
TRANSISTOR

Required Special Tools:

• MB992044: ECU Check Harness

.

Measurement Method

1. Disconnect the all ECU connectors, and connect check har-

ness special tool (MB992044) between the separated con-
nectors.

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

nector terminal to analyze each cylinder:

• Terminal No. 151 for the number 1 cylinder.

• Terminal No. 150 for the number 2 cylinder.

• Terminal No. 144 for the number 3 cylinder.

• Terminal No. 148 for the number 4 cylinder.

• Terminal No. 143 for the number 5 cylinder.

• Terminal No. 134 for the number 6 cylinder.

Standard Wave Pattern

AKX01605

WHEN IDLING

WHEN RACING

AB

Observation condition

Function

Special pattern

Pattern height

Low

Pattern selector

Display

Engine r/min

Idle speed

03DB246A

OSCILLOSCOPE

POWER PLANT ECU

CHECK HARNESS

CONNECTOR

MULTIPORT FUEL INJECTION (MPI) DIAGNOSIS

MULTIPORT FUEL INJECTION (MPI) <3.8L ENGINE>

13A-657

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

advanced when the engine speed is increased.

.

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.

CONDITION OF WAVE
PATTERN BUILD-UP
SECTION AND MAXIMUM
VOLTAGE

PROBABLE CAUSE

Voltage value is too low

Open-circuit in ignition primary
circuit

AK203308

TDC

5˚BTDC

ON

TIME

AC

OFF

CRANKSHAFT

POSITION

SENSOR OUTPUT

WAVE PATTERN

IGNITION POWER

TRANSISTOR

CONTROL SIGNAL

WAVE PATTERN

Standard wave pattern

IGNITION

TIMING

DWELL

SECTION

5

10

0

0

2 ENGINE REVOLUTIONS (1 CAMSHAFT REVOLUTION)

(VOLT)

AK203246

NORMAL WAVE

PATTERN

AC

SPECIAL TOOLS

MULTIPORT FUEL INJECTION (MPI) <3.8L ENGINE>

13A-658

SPECIAL TOOLS

M1131000601293

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

A: MB991824
B: MB991827
C: MB991910
D: MB991911
E: MB991914
F: MB991825
G: MB991826
MUT-III sub assembly
A: Vehicle
Communication Interface
(V.C.I.)
B: MUT-III USB Cable
C: MUT-III Main Harness
A (Vehicles with CAN
communication system)
D: MUT-III Main Harness
B (Vehicles without CAN
communication system)
E: MUT-III Main Harness
C (for Daimler Chrysler
models only)
F: MUT-III Measurement
Adapter
G: MUT-III Trigger
Harness

MB991824-KIT

NOTE: G: MB991826
MUT-III Trigger Harness
is not necessary when
pushing V.C.I. ENTER
key.

• Reading diagnostic

trouble code

• MFl system inspection

• Measurement of fuel

pressure

CAUTION

For vehicles with CAN
communication, use
MUT-III main harness A
to send simulated
vehicle speed. If you
connect MUT-III main
harness B instead, the
CAN communication
does not function
correctly.

MB992044
ECU check harness

MD998478-01

• lnspection using an

oscilloscope

• lnspection of the

electronic control unit
(ECU) terminal voltage
check

MB991910

MB991826

MB991958

MB991911

MB991914

MB991824

MB991827

MB991825

DO NOT USE

A

B

C

D

E

F

G

DO NOT USE

SPECIAL TOOLS

MULTIPORT FUEL INJECTION (MPI) <3.8L ENGINE>

13A-659

MD998478
Test harness (3 pin,
triangle)

MD998478-01

• Inspection using an

oscilloscope

MB991637
Fuel pressure gauge set

Tool not available

• Measurement of fuel

pressure

TBA
Adaptor hose

Measurement of fuel
pressure

TOOL

TOOL NUMBER AND
NAME

SUPERSESSION

APPLICATION

MB991637

03DB257A