Mitsubishi Evolution X. Manual - part 252

FUEL SUPPLY DIAGNOSIS

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FUEL SUPPLY

13B-3

SYMPTOM PROCEDURES

M1135004800414

Inspection Procedure 1 : Engine Malfunctions Due to Insufficient Fuel Supply

TROUBLESHOOTING HINTS (The most likely causes for 

this case:)

• Fuel injector failed.

• Open or shorted fuel injector circuit, or loose connector.

• Bent, twisted or clogged fuel main pipe or fuel high-pres-

sure hose.

• Malfunction of the fuel tank pump and gauge assembly.

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, read the MFI system 
diagnostic trouble code.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Ensure that the ignition switch is at the "LOCK" (OFF) 

position.

(2) Start up the personal computer.
(3) Connect special tool MB991827 to special tool MB991824 

and the personal computer.

(4) Connect special tool MB991910 to special tool MB991824.
(5) Connect special tool MB991910 to the data link connector.
(6) Turn the power switch of special tool MB991824 to the "ON" 

position.
NOTE: When special tool MB991824 is energized, special 
tool MB991824 indicator light will be illuminated in a green 
color.

(7) Start the M.U.T.-III system on the personal computer.
(8) Turn the ignition switch to the "ON" position.
(9) Check for MFI system diagnostic trouble code (Refer to 

GROUP 13A, Diagnostic Function 

− How to Read and Erase 

Diagnostic Trouble Codes 

P.13A-9

).

(10)Turn the ignition switch to the "LOCK" (OFF) position, and 

then remove scan tool MB991958 in the reverse order of 
installation.

Q: Is the DTC set?

YES : Repair MFI system (Refer to GROUP 13A, Diagnostic 

Trouble Code Chart 

P.13A-44

). Then go to Step 6.

NO :  Go to Step 2.

FUEL SUPPLY DIAGNOSIS

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FUEL SUPPLY

13B-4

STEP 2. Check the fuel pressure.
Release residual pressure from the fuel line to prevent fuel 
spray (Refer to GROUP 13A, On-vehicle Service 

− Fuel Pres-

sure Test 

P.13A-897

).

Q: Is the fuel pressure in good condition?

YES : Go to Step 5.
NO :  Go to Step 3.

STEP 3. Check for bending, twisting or clogging of the fuel 
main pipe and fuel high-pressure hose.

AC709312 AB

Fuel main pipe

Fuel high-pressure hose

Q: Are the fuel main pipe and fuel high-pressure hose in 

good condition?
YES : Go to Step 4.
NO :  Repair or replace the fuel main pipe or fuel 

high-pressure hose. Then go to Step 6 .

STEP 4. Check the fuel pump operation.
Refer to GROUP 13A, On-vehicle Service 

− Fuel Pump Opera-

tion Check 

P.13A-901

.

Q: Is the fuel pump module operation in good condition?

YES : Go to Step 5.
NO :  Replace the fuel tank pump and gauge assembly 

(Refer to 

P.13B-6

). Then go to Step 6.

STEP 5. Check the inside of the fuel tank for contamination 
and rust.
Remove the fuel tank (Refer to 

P.13B-10

).

Q: Is the fuel tank in good condition?

YES : Go to Step 6.
NO :  Replace the fuel filter, and clean the fuel tank and fuel 

line. Then go to Step 6 .

STEP 6. Retest the system.
Q: Is the engine malfunction eliminated?

YES : The procedure is complete.
NO :  Return to Step 1.

SPECIAL TOOLS

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FUEL SUPPLY

13B-5

SPECIAL TOOLS

M1135000600753

Tool

Tool number and name

Supersession

Application

MB991910

MB991826

MB991958

MB991911

MB991914

MB991824

MB991827

MB991825

DO NOT USE

a

b

c

d

e

f

g

DO NOT USE

MB991958
Scan tool (M.U.T.-III sub 
assembly)

a: MB991824

Vehicle communication 
interface (V.C.I.)

b: MB991827

M.U.T.-III USB cable

c: MB991910

M.U.T.-III main harness 
A (Vehicles with CAN 
communication 
system)

d: MB991911

M.U.T.-III main harness 
B (Vehicles without 
CAN communication 
system)

e: MB991914

M.U.T.-III main harness 
C (for Daimler Chrysler 
models only)

f: MB991825

M.U.T.-III adapter 
harness

g: MB991826

M.U.T.-III trigger 
harness

MB991824-KIT
NOTE: MB991826 
M.U.T.-III Trigger 
Harness is not 
necessary when 
pushing V.C.I. ENTER 
key.

For vehicles with CAN 
communication, use 
M.U.T.-III main harness A 
to send simulated vehicle 
speed. If you connect 
M.U.T.-III main harness B 
instead, the CAN 
communication does not 
function correctly.
Checking diagnostic trouble 
code

MB991658

MB991658
Test harness set

Tool not available

Fuel tank differential 
pressure sensor check

CAUTION

ON-VEHICLE SERVICE

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FUEL SUPPLY

13B-6

ON-VEHICLE SERVICE

FUEL PUMP OPERATION CHECK

M1135001000635

Refer to GROUP 13A, On-vehicle Service 

− Fuel Pump Opera-

tion Check 

P.13A-901

.

FUEL LEVEL SENSOR (SUB) CHECK

M1135005300133

Refer to GROUP 54A, Combination Meter 

− On-vehicle Service, 

Fuel Level Sensor (sub) Check 

P.54A-91

.

FUEL PUMP MODULE REPLACEMENT

M1135004901221

1. Remove the rear seat cushion assembly. (Refer to GROUP 

52A, Rear Seat Assembly 

P.52A-25

).

AC703013

AE

Floor inspection lid (LH)

2. Remove the floor inspection lid (LH).

AC709179AC

Fuel main pipe

Fuel tank differential
pressure sensor connector

Fuel tank
pump module
connector

Fuel return hose

3. Disconnect the fuel pump module connector and fuel tank 

differential pressure sensor connector.

4. Release the fuel pressure in the fuel line. [Refer to GROUP 

13A, On-vehicle Service 

− Fuel Pump Connector 

Disconnection (How to Reduce Pressurized Fuel Lines) 

P.13A-901

].

5. Disconnect the fuel return hose.

AC606017

Fuel pump module

Retainer

Flat-tip
screwdriver

Fuel main pipe

AC

6. Insert a flat-tip screwdriver [6mm (0.24 inch) wide and 1mm 

(0.04 inch) thick] into the retainer of the fuel main pipe.