Mitsubishi Lancer Evolution X. Manual - part 417

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-733

Inspection procedure 10: When the engine is cold, it stalls at idle (die out)

.

COMMENT

• In such cases as the above, the air/fuel mixture 

may be inappropriate when the engine is cold.

.

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

• Malfunction of the fuel pump system.
• Malfunction of the ignition system.
• Poor compression.
• Improper engine oil viscosity.
• 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

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 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.

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.

(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.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-734

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 6: Engine Coolant Temperature Sensor.

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

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

symptom is eliminated.

STEP 4. 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 5.
NO :  Check for installed conditions of the timing chain. 

Then confirm that the malfunction symptom is 
eliminated. 

STEP 5. Check the fuel pressure.
Refer to Fuel Pressure Test 

P.13A-865

.

Q: Is the fuel pressure normal?

YES : Go to Step 6.
NO :  Repair or replace it. Then confirm that the malfunction 

symptom is eliminated.

STEP 6. 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 7.

STEP 7. 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 8.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-735

STEP 8. 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 engine oil viscosity, and replace the engine 

oil.

Then confirm that the malfunction symptom is 

eliminated.

NO :  Repair it. Then confirm that the malfunction symptom 

is eliminated.

Inspection procedure 11: When the engine is hot, it stalls at idle (die out)

.

COMMENT

• In cases such as the above, the ignition system, 

air/fuel mixture or compression pressure may be 
faulty. In addition, if the engine suddenly stalls, 
the cause may also be a connector damage.

.

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

• Malfunction of the fuel pump system.
• Malfunction of the ignition system.
• Poor compression
• Improper operation of the PCV valve.
• Vacuum leak.
• Dirtiness around throttle valve.
• 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

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-736

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 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.

STEP 2. Using scan tool MB991958, check actuator test 
item 1: injector.
(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.

(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 13: Throttle position sensor (main).

(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.

AC608435

Data link connector

MB991827

MB991824

MB991910

AB