Mitsubishi Montero Sport (2004+). Manual - part 300

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-613

(7) Disconnect the hand vacuum pump, and connect hose M to 

the evaporative emission ventilation solenoid.

Q: Does the evaporative emission ventilation solenoid hold 

vacuum?
YES : Go to Step 5 .
NO :  Replace the evaporative emission ventilation solenoid 

(Refer to GROUP 17, Evaporative Emission Canister 
and Fuel Tank Pressure Relief Valve 

P.17-116

). Then 

go to Step 19 .

STEP 5. Check for leaks the evaporator line hose M.
Perform a leakage test with a hand vacuum pump on hose M.
Q: Does the hose N hold vacuum?

YES : Go to Step 6 .
NO :  Replace the damaged hose M (Refer to GROUP 17, 

Evaporative Emission Canister and Fuel Tank 
Pressure Relief Valve 

P.17-116

). Then go to Step 19 .

STEP 6. Check for vacuum leaks and clogging in 
evaporator line hose D.
Perform a leakage test with a hand vacuum pump on hose D.
Q: Does the hose D hold vacuum?

YES : Go to Step 7 .
NO :  Replace the damaged hose D. (Refer to GROUP 17, 

Evaporative Emission Canister and Fuel Tank 
Pressure Relief Valve 

P.17-116

). Then go to Step 19 .

AC004932

HOSE M

AF

AC004932

HOSE D

AG

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-614

STEP 7. Pressure test the evaporative emission system 
lines between hose E, L and the fuel tank.
(1) Disconnect hose E from the canister side, and plug the 

hose.

(2) Remove the fuel cap.
(3) Confirm that the evaporative emission system pressure 

pump (Miller number 6872A) is operating properly. Perform 
the self-test as described in the manufacturer's instructions.

(4) Connect the evaporative emission system pressure pump 

to the fuel filler neck.

(5) Pressure test the system to determine whether any leaks 

are present.
NOTE: The "Pressure test" in this procedure refers to the 
I/M240 Simulation Test. The eight steps of this test are 
described in the manufacturer's instructions for the evapo-
rative emission system pressure pump, Miller number 
6872A.

(6) Disconnect the evaporative emission system pressure 

pump, and reinstall the fuel cap.

(7) Connect hose G to the evaporator line.
Q: Is the evaporative emission system line free of leaks?

YES : Go to Step 15 .
NO :  Go to Step 8 .

STEP 8. Check for vacuum leaks in the evaporative 
emission system hose E.
Perform a leakage test with a hand vacuum pump on hose E.
Q: Does the hose N hold vacuum?

YES : Go to Step 9 .
NO :  Replace the damaged hose E. (Refer to GROUP 17, 

Evaporative Emission Canister and Fuel Tank 
Pressure Relief Valve 

P.17-116

). Then go to Step 19 .

AC005140

HOSE E

AC

ACX01358

AC004932

HOSE E

AH

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-615

STEP 9. Pressure test the evaporative emission system 
from hoses F through J.
(1) Remove the fuel filler neck protector. (Refer to GROUP 

13B, Fuel Tank 

P.13B-6

).

(2) Perform a leakage test with a hand vacuum pump on hose 

F through J.

Q: Do the hoses hold vacuum?

YES : Go to Step 10 .
NO :  Replace any damaged hose and reinstall the fuel filler 

neck protector. (Refer to GROUP 13B, Fuel Tank 

P.13B-6

). Then go to Step 19 .

STEP 10. Check the check valve A.
(1) Check valve A is a one-way check valve.
(2) Check valve A should allow air to flow in only one direction.
Q: Does check valve A allow air to flow in one direction 

only?
YES : Go to Step 11 .
NO :  Replace check valve A, and reinstall the fuel tank filler 

neck protector. (Refer to GROUP 13B, Fuel Tank 

P.13B-6

). Then go to Step 19 .

STEP 11. Check the check valve B.
(1) Check valve B is an one-way check valve.
(2) Check valve B should allow air to flow in only one direction.
(3) When you blow the check valve, on air should leak from the 

check valve body.

Q: Does check valve B allow air to flow in one direction 

only?
YES : Go to Step 12 .
NO :  Replace check valve B, reinstall the fuel filler neck 

protector. (Refer to GROUP 13B, Fuel Tank 

P.13B-6

). 

Then go to Step 19 .

AC004933AD

HOSE I

HOSE G

HOSE H

HOSE J

HOSE F

AC002076 AB

CHECK VALVE A

AC002078

CHECK VALVE B

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-616

STEP 12. Check for leaks in the evaporative emission 
system hoses K through L.
(1) Remove the fuel tank. (Refer to GROUP 13B, Fuel Tank 

P.13B-6

).

(2) Perform a leakage test with a hand vacuum pump on each 

hose from hose P through S.

Q: Do the hoses hold vacuum?

YES : Go to Step 13 .
NO :  Replace the damaged hose, and reinstall the fuel 

tank. (Refer to GROUP 13B, Fuel Tank 

P.13B-6

). 

Then go to Step 19 .

STEP 13. Check for leak in the fuel tank.
(1) Visually check for cracks and leaks, etc.

NOTE: Carefully check the fuel pump assembly and the 
inner pressure sensor installation section in the fuel tank.

(2) Connect the evaporative emission system pressure pump 

to the filler hose.

(3) Plug the fuel pump feed nipple, return hose, hose K and 

hose L connected to the fuel tank.
NOTE: If these items are not securely plugged at this time, 
the fuel could leak from the tank.

(4) Pressurize the fuel tank with the evaporative emission 

system pressure pump.

(5) In the pressurized state, check for the leaks by applying 

soapy water solution to each section and look for bubbles.

Q: Are any leaks found?

YES <When there is a leak from the attachment points of 
the fuel pump assembly, the fuel tank differential 
pressure sensor or the fuel tank rollover valve.> : 

Reassemble the leaked parts and check again that 
there are no leaks. Then reinstall the fuel tank (Refer 
to GROUP 13B, Fuel Tank 

P.13B-6

). Then go to Step 

19 .

YES <When there is a leak from the fuel tank.> : Replace 

the fuel tank (Refer to GROUP 13B, Fuel Tank 

P.13B-6

). Then go to Step 19 .

NO :  When there is no leak, reinstall the fuel tank (Refer to 

GROUP 13B, Fuel Tank 

P.13B-6

). Then go to Step 14 

.

AC004930

HOSE K

HOSE L

AC

AC005139

AC005138