Mitsubishi Eclipse / Eclipse Spyder (2000-2002). Service and repair manual — part 339

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-555

9. Disconnect the vacuum hose (blue stripe) from the fuel

pressure regulator and measure fuel pressure with the hose
end closed with your finger.

Standard value: 330

−

350 kPa (47

−

50 psi) at curb idle

10.Check to see that fuel pressure at idle does not drop even

after the engine has been revved several times.

11.Revving the engine repeatedly, hold the fuel return hose

lightly with your fingers to feel that fuel pressure is present in
the return hose.

NOTE: If the fuel flow rate is low, there will be no fuel
pressure in the return hose.

12.If any of fuel pressure measured in steps 8 to 11 is out of

specification, troubleshoot and repair according to the table
below.

13.Stop the engine and observe fuel pressure gauge reading. It

is normal if the reading does not drop within two minutes. If it
does, observe the rate of drop and troubleshoot and repair
according to the table below. Start, then stop the engine.

(1) Squeeze the fuel return line closed to confirm leak-down

occurs from defective fuel pressure regulator.

(2) Squeeze the fuel supply line closed to confirm leak-down

occurs from defective fuel pump check valve.

(3) If pressure continues to drop with both fuel lines

squeezed closed, injector(s) are leaking.

14.Release residual pressure from the fuel pipe line (Refer to

P.13B-556

.)

SYMPTOM

PROBABLE CAUSE

REMEDY

•

Fuel pressure too low

•

Fuel pressure drops after racing

•

No fuel pressure in fuel return
hose

Clogged fuel filter

Replace fuel filter

Fuel leaking to return side due to
poor fuel regulator valve seating or
settled spring

Replace fuel pressure regulator

Low fuel pump delivery pressure

Replace fuel pump

Fuel pressure too high

Binding valve in fuel pressure
regulator

Replace fuel pressure regulator

Clogged fuel return hose or pipe

Clean or replace hose or pipe

Same fuel pressure when vacuum
hose is connected and when
disconnected

Damaged vacuum hose or
clogged nipple

Replace vacuum hose or clean
nipple

Defective fuel pressure regulator

Replace fuel pressure regulator

SYMPTOM

PROBABLE CAUSE

REMEDY

Fuel pressure drops gradually after
engine is stopped

Leaky injector

Replace injector

Leaky fuel regulator valve seat

Replace fuel pressure regulator

Fuel pressure drops sharply
immediately after engine is stopped

Check valve in fuel pump is held
open

Replace fuel pump

AK000119

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-556

WARNING

Cover the hose connection with shop towels to
prevent splash of fuel that could be caused by some
residual pressure in the fuel pipe line.

15.Remove the fuel pressure gauge, and special tools

MD998709, MD998742 and MB991637 from the fuel rail.

16.Replace the O-ring at the end of the high-pressure fuel hose

with a new one.

17.Fit the high-pressure fuel hose into the fuel rail and tighten

the bolts to specified torque.

Tightening torque: 4.9

±

1.0 N

⋅

m (43

±

8 in-lb)

18.Check for fuel leaks.

(1) Use scan tool MB991502 to operate the fuel pump.
(2) Check the fuel line for leaks and repair as needed.

19.Disconnect scan tool MB991502.

FUEL PUMP CONNECTOR
DISCONNECTION(HOW TO REDUCE
PRESSURIZED FUEL LINES)

M1131000900161

Refer to GROUP 13A, On-vehicle Service

−

Fuel Pump Relay

Disconnection (How to Reduce Pressurized Fuel Lines)

P.13A-

478

.

FUEL PUMP OPERATION CHECK

M1131002000153

Refer to GROUP 13A, On-vehicle Service

−

Fuel Pump

Operation Check

P.13A-478

.

MULTIPORT FUEL INJECTION (MFI) RELAY AND
FUEL PUMP RELAY CONTINUITY CHECK

M1131009900094

Refer to GROUP 13A, On-vehicle Service

−

Multiport Fuel

Injection (MFI) Relay and Fuel Pump Relay Continuity Check
(

P.13A-479

).

INTAKE AIR TEMPERATURE SENSOR CHECK

M1131002800085

Refer to GROUP 13A, On-vehicle Service

−

Intake Air

Temperature Sensor Check (

P.13A-479

).

ENGINE COOLANT TEMPERATURE SENSOR
CHECK

M1131003100089

Refer to GROUP 13A, On-vehicle Service

−

Engine Coolant

Temperature Sensor Check (

P.13A-479

).

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-557

THROTTLE POSITION SENSOR CHECK

M1131003200064

Required Special Tool:
MB991348: Test Harness Set
Checking the Terminal Resistance
1. Disconnect the throttle position sensor connector.

2. Measure the resistance between throttle position sensor

side connector terminals 1 and 4.

Standard value: 3.5

−

6.5 k

Ω

3. Measure the resistance between throttle position sensor

side connector terminals 1 and terminal 3.

Normal condition:

4. If the resistance is outside the standard value, or if it doesn't

change smoothly, replace the throttle position sensor.

NOTE: After replacement, the throttle position sensor should
be adjusted. (Refer to

P.13B-552

.)

Check using oscilloscope
1. Disconnect the throttle position sensor connector and

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

2. Connect the oscilloscope probe to the throttle position

sensor side connector terminal 3.

3. Turn the ignition switch to the "ON" position.

4. Slowly move the throttle lever from the idle position to the

full-throttle position and check then if the waveform is free
from any noise.

5. If any noise is recognized, replace the throttle position

sensor.

NOTE: After replacement, the throttle position sensor should
be adjusted. (Refer to

P.13B-552

.)

HEATED OXYGEN SENSOR CHECK

M1131005000107

Required Special Tools:
MD998464: Test Harness
MB991316: Test Harness
MB991658: Test Harness Set

Throttle valve slowly open
until fully open from the idle
position

Changes smoothly in
proportion to the opening
angle of the throttle valve

AKX01413

THROTTLE POSITION
SENSOR CONNECTOR

1 2 3 4

AB

AKX01461AB

THROTTLE POSITION
SENSOR CONNECTOR

OSCILLOSCOPE

1 2 3 4

AKX01462AB

NORMAL WAVEFORM

THROTTLE LEVER
FULL-THROTTLE
POSITION

THROTTLE
LEVER
IDLE
POSITION

ON-VEHICLE SERVICE

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.0L ENGINE>

13B-558

<Right bank and left bank heated oxygen sensor (front)>
1. Use scan tool MB991502, observe HO

2

S reading. If values

are unsatisfactory, or if the scan tool is not available, use the
following procedure:

(1) Disconnect the heated oxygen sensor connector and

connect special tool MD998464 to the connector on the
heated oxygen sensor side.

(2) Make sure that there is continuity [4.5

−

8.0 ohm at 20

°

C

(68

°

F

)

] between terminal 1 (red clip of special tool) and

terminal 3 (blue clip of special tool) on the heated oxygen
sensor connector.

(3) If there is no continuity, replace the heated oxygen

sensor.

(4) Warm up the engine until engine coolant is 80

°

C (176

°

F

)

ορ ηιγηερ.

CAUTION

Be very careful when connecting the jumper wires;
incorrect connection can damage the heated oxygen
sensor.

(5) Use the jumper wires to connect terminal 1 (red clip) of

the heated oxygen sensor connector to the positive
battery terminal and terminal 3 (blue clip) to the negative
battery terminal.

(6) Connect a digital voltage meter between terminal 2 (black

clip) and terminal 4 (white clip).

2. While repeatedly revving the engine, measure the heated

oxygen sensor output voltage.

Standard value:

3. If the sensor is defective, replace the heated oxygen sensor.

NOTE: For removal and installation of the heated oxygen
sensor, refer to GROUP 15, Exhaust Pipe and Main Muffler
(

P.15-21

).

ENGINE

HEATED OXYGEN
SENSOR OUTPUT
VOLTAGE

REMARKS

When revving
engine

0.6

−

1.0V

If you make the air/fuel
ratio rich by revving the
engine repeatedly, a
normal heated oxygen
sensor will output a
voltage of 0.6

−

1.0V.

AKX01624

HEATED
OXYGEN
SENSOR
EQUIPMENT
SIDE
CONNECTOR

MD998464

BLUE

RED

AC

AKX01625AC

BLUE

RED

BLACK

JUMPER
WIRES

WHITE

MD998464