Mitsubishi Lancer Evolution X. Manual - part 326

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-369

STEP 6. Check the following items.
(1) Check the following items, and repair or replace the 

defective component.

a. Check for skipped timing chain teeth.
b. Check compression.

Q: Are there any abnormalities?

YES : Repair or replace it. Then go to Step 8.
NO :  Go to Step 7.

STEP 7. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 14 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0300 set?

YES : Replace the ECM. When the ECM is replaced, 

register the ID code. Refer to GROUP 42B, ID Code 
Registration Necessity Judgment Table <Vehicles 
with KOS> 

P.42B-11

 or GROUP 42C, ID Codes 

Registration Judgment Table <Vehicles with WCM> 

P.42C-9

. Then go to Step 8.

NO :  It can be assumed that this malfunction is intermittent. 

Refer to GROUP 00, How to Use 
Troubleshooting/Inspection Service Points − How to 

Cope with Intermittent Malfunctions 

P.00-15

.

STEP 8. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function − OBD-II Drive Cycle − Pattern 14 

P.13A-9

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0300 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-370

DTC P0301: Cylinder 1 Misfire Detected

.

TECHNICAL DESCRIPTION

• If a misfire occurs while the engine is running, the 

engine speed changes for an instant.

• The ECM checks for such changes in engine 

speed.

.

DESCRIPTIONS OF MONITOR METHODS

Monitor angular acceleration of crankshaft and 

detect malfunction when negative variation of the 
angular acceleration is large.

.

MONITOR EXECUTION

Continuous

.

MONITOR EXECUTION CONDITIONS 
(Other monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Not applicable

Sensor (The sensor below is determined to be 

normal)

• Camshaft position sensor
• Mass airflow sensor
• Engine coolant temperature sensor
• Intake air temperature sensor
• Barometric pressure sensor
• Throttle position sensor

.

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-371

DTC SET CONDITIONS

Logic Flow Chart

Check Conditions

• Engine speed is between 438 and 7,000 r/min.
• Engine coolant temperature is higher than −10° C 

(14° F).

• Barometric pressure is higher than 76 kPa (22.4 

in.Hg).

• The engine load is with in the positive torque 

load.

Calculate crankshaft

angular acceleration (An)

Misfire

Calculate percent misfire (R

MF

)

End

No

No

No

No

No

No

Yes

Good

Within 1000rev

Malfunction

(exceed std × 1.5)

Good

Malfunction (catalytic

converter is damaged.)

Good

Calculate percent misfire (R

MF

)

Within 200rev

Ne
Ec     : Charge efficiency
TH

MF

 : Threshold value for misfire

TH

CD

 : Threshold value for catalyst damage

AK800585

Start

Yes

Yes

Yes

Yes

Yes

Monitoring
conditions

An < TH

MF

 (Ne, Ec)

R

MF

 

>= specified value

R

MF

 >= TH

CD

 (Ne, Ec)

: Engine speed

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI)

13A-372

• Adaptive learning is complete for the vane which 

generates a crankshaft position signal.

• While the engine is running, excluding rough road 

driving <M/T>, sudden acceleration/deceleration 
and fuel shut-off operation.

Judgement Criteria (change in the angular accel-

eration of the crankshaft is used for misfire 
detection)

• Misfire has occurred more frequently than 

allowed during the last 200 revolutions [when the 
catalyst temperature is higher than 1,000° C 

(1,832° F)].

or

• Misfire has occurred in 2.0 percent or more of the 

last 1,000 revolutions (corresponding to 1.5 times 
the limit of emission standard).

.

FAIL-SAFE AND BACKUP FUNCTION

• The supply of fuel to the misfiring cylinder can 

possibly be cut.

.

OBD-II DRIVE CYCLE PATTERN

Refer to Diagnostic Function − OBD-II Drive Cycle − 

Pattern 14 

P.13A-9

.

.

TROUBLESHOOTING HINTS (The most 
likely causes for this code to be set are:)

• Ignition system related part(s) failed.
• Low compression pressure.
• ECM failed. 

DIAGNOSIS

STEP 1. Visual check on ignition spark of No. 1 cylinder.
(1) Remove the spark plug and install it to the ignition coil.
(2) Connect the ignition coil connector.
(3) Remove all injector connector.
(4) At the engine start, check spark plug produces a spark.
Q: Did it spark?

YES : Go to Step 3.
NO :  Go to Step 2.

STEP 2. Check the No. 1 cylinder spark plug.
Refer to GROUP 16, Ignition System − On-vehicle Service − 

Spark Plug Check And Cleaning 

P.16-38

.

Q: Is the spark plug normal?

YES : Refer to, Symptom Procedures 26 − Ignition Circuit 

System 

P.13A-808

.

NO :  Replace the No. 1 cylinder spark plug. Then go to 

Step 5.

STEP 3. Check the compression.
Refer to GROUP 11A, On-vehicle Service − Compression Pres-

sure Check 

P.11A-15

.

Q: Are there any abnormalities?

YES : Repair or replace it. Then go to Step 5.
NO :  Go to Step 4.

AK704268 AB

Spark plug