Mitsubishi Lancer Evolution X. Manual - part 414

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

13A-721

STEP 9. Check harness connector A-34X at MFI relay and
harness connector A-25X at injector relay connector for
damage.
Q: Is the harness connector in good condition?

YES : Go to Step 10.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then confirm that the

malfunction symptom is eliminated.

STEP 10. Check for harness damage between MFI relay
connector A-34X (terminal No. 2) and injector relay
connector A-25X (terminal No. 4).
Q: Is the harness wire in good condition?

YES : Go to Step 11.
NO : Repair it. Then confirm that the malfunction symptom

is eliminated.

STEP 11. 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 12.
NO : Repair it. Then confirm that the malfunction symptom

is eliminated.

STEP 12. 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 13.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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MULTIPORT FUEL INJECTION (MFI)

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STEP 13. Check the ignition coil.
(1) Remove the intake manifold.
(2) 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 14.

STEP 14. 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 fuel lines for clogging.
b. Check if fuel is contaminated.

c. 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.

Inspection procedure 6: Hard starting

COMMENT

• In cases such as the above, the cause is usually

either weak spark, improper air-fuel mixture or
low compression.

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
• Contaminated fuel.
• 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)

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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 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 data list.
(1) Turn the ignition switch the "ON" position.
(2) Check the following items in the data list. Refer to Data List

Reference Table

P.13A-818

a. Item 1: Power Supply Voltage.
b. Item 6: Engine Coolant Temperature Sensor.

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

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

symptom is eliminated.

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

Actuator Test Reference Table

P.13A-840

a. Item 9: Fuel Pump.

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

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

symptom is eliminated.

AC608435

Data link connector

MB991827

MB991824

MB991910

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

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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 : Repair or replace. 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. Then confirm that the malfunction

symptom is eliminated.

STEP 6. Check harness connector B-101, B-102, B-103,
B-104 at injector for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 7.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then confirm that the

malfunction symptom is eliminated.

STEP 7. Check the injector resistance.
(1) Disconnect the left bank injector connector B-101, B-102,

B-103, B-104.

(2) Measure the resistance between each injector side

connector terminal No. 1 and No. 2.

Standard value: 10.5 − 13.5 Ω [at 20° C (68° F)]

Q: Is the measured resistance between 10.5 and 13.5 ohms

[at 20° C (68° F)]?
YES : Go to Step 8.
NO : Replace the faulty injector. Then confirm that the

malfunction symptom is eliminated.

STEP 8. Check harness connector A-25X at injector relay
for damage.
Q: Is the harness connector in good condition?

YES : Go to Step 9.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

. Then confirm that the

malfunction symptom is eliminated.

AK604038

1 2

Injector side
connector

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