Mitsubishi Lancer Evolution X. Manual - part 415

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-725

STEP 9. Check for harness damage between injector relay 
connector and injector connector.
NOTE: Check harness after checking intermediate connector 
A-39. If intermediate connector is damaged, repair or replace it. 
Refer to GROUP 00E, Harness Connector Inspection 

P.00E-2

. 

Then confirm that the malfunction symptom is eliminated.

a. Injector relay connector A-25X (terminal No. 3) and No. 1 

cylinder injector connector B-101 (terminal No. 1).

b. Injector relay connector A-25X (terminal No. 3) and No. 2 

cylinder injector connector B-102 (terminal No. 1).

c. Injector relay connector A-25X (terminal No. 3) and No. 3 

cylinder injector connector B-103 (terminal No. 1).

d. Injector relay connector A-25X (terminal No. 3) and No. 4 

cylinder injector connector B-104 (terminal No. 1).

Q: Is the harness wire in good condition?

YES : Go to Step 10.
NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

STEP 10. Check harness connector B-09 at ECM for 
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 11.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then confirm that the 

malfunction symptom is eliminated.

STEP 11. Check for open circuit and short circuit to ground 
and harness damage between injector connector and ECM 
connector.

a. No. 1 cylinder injector connector B-101 (terminal No. 2) and 

ECM connector B-09 (terminal No. 2).

b. No. 2 cylinder injector connector B-102 (terminal No. 2) and 

ECM connector B-09 (terminal No. 3).

c. No. 3 cylinder injector connector B-103 (terminal No. 2) and 

ECM connector B-09 (terminal No. 18).

d. No. 4 cylinder injector connector B-104 (terminal No. 2) and 

ECM connector B-09 (terminal No. 19).

Q: Is the harness wire in good condition?

YES : Go to Step 12.
NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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STEP 12. Check the ignition system.
(1) Connect the timing light to terminal No. 4 of the ignition coil 

connector B-02, B-03, B-04 or B-06 in order.

(2) Crank the engine.

• The timing light flashes.

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Does the timing light flash?

YES : Go to Step 13.
NO :  Refer to Inspection procedure 25 − Ignition circuit 

system 

P.13A-808

.

STEP 13. Check the spark plugs.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Spark Plug Check And Cleaning 

P.16-39

.

Q: Are there any abnormalities?

YES : Replace the spark plug. Then confirm that the 

malfunction symptom is eliminated.

NO :  Go to Step 14.

STEP 14. Check the ignition coil.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Ignition Coil Check 

P.16-37

.

Q: Are there any abnormalities?

YES : Replace the ignition coil. Then confirm that the 

malfunction symptom is eliminated.

NO :  Go to Step 15.

STEP 15. Check the compression pressure.
Refer to GROUP 11A, On-vehicle Service − Compression Pres-

sure Check 

P.11A-15

.

Q: Is the compression pressure normal?

YES : Check the following items, and repair or replace the 

defective items.

a. Check if fuel is contaminated.
b. Check if the injectors are clogged.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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Inspection procedure 7: Unstable idle (rough idle, hunting)

.

COMMENT

• In cases such as the above, the cause is proba-

bly the air/fuel mixture. Other systems affecting 
idle quality include the ignition system and com-
pression.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this case:)

• Malfunction of the fuel pump system.
• Malfunction of the ignition system.

• Malfunction of the injector system.
• Poor compression
• Malfunction of the purge control system
• Improper operation of the PCV valve.
• Malfunction of the charging system.
• Vacuum leak.
• Contaminated fuel.
• Malfunction of variable valve timing control 

(MIVEC) system.

• Malfunction of the ECM.

DIAGNOSIS

Required Special Tools:

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

• MB991824: V.C.I.
• MB991827: USB Cable
• MB991910: Main Harness A

• MB992110: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, read the diagnostic 
trouble code (DTC)

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch is to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is any DTC set?

YES : Refer to Diagnostic Trouble Code Chart 

P.13A-48

.

NO :  Go to Step 2.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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STEP 2. Using scan tool MB991958, check actuator test.
(1) Turn the ignition switch to the "ON" position.
(2) Check following items in the actuator test. Refer to Actuator 

Test Reference Table 

P.13A-840

.

a. Item 1: Injector.
b. Item 10: Evaporative emission purge solenoid

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?

YES : Go to Step 3.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 3. Using scan tool MB991958, check data list.
(1) Turn the ignition switch to the "ON" position.
(2) Check the following items in the data list. Refer to Data List 

Reference Table 

P.13A-818

.

a. Item 5: Intake Air Temperature Sensor.
b. Item 6: Engine Coolant Temperature Sensor.

c. Item 10: Mass Airflow Sensor

d. Item 36: Intake V.V.T. phase angle
e. Item 39: Exhaust V.V.T. phase angle

f. Item 76: A/C Switch

(3) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are they operating properly?

YES : Go to Step 4.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 4. Check the fuel pressure.
Refer to Fuel Pressure Test 

P.13A-865

.

Q: Is the fuel pressure normal?

YES : Go to Step 5.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 5. Check the ignition timing.
Refer to GROUP 11A, On-vehicle Service − Ignition Timing 

Check 

P.11A-10

.

Q: Is the ignition timing normal?

YES : Go to Step 6.
NO :  Check for installed conditions of the timing chain. 

Then confirm that the malfunction symptom is 
eliminated.