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Alfa Romeo 147 Factory Service Manual (2000-2004)22 · Fault diagnosis
22 · Diagnostics

Misfire error in one cylinder

Make
Alfa Romeo
Model
147 Factory Service Manual
Year
2000–2004
Section
Examiner › Misfire error in one cylinder
Fault diagnosisMisfire error in one cylinder

MISFIRE ERROR IN ONE CYLINDER

1.6 TS, 2.0 TS

The diagnostic equipment signals the following error: Misfire in cylinder X

Carry out the procedure for the circuit for the cylinder in which the error was detected

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Check that the ignition circuit is correctly connected and working properly, paying particular attention to:

Continue to Step 1Faults in the electrical circuit

Restore correct connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT. If necessary, replace the faulty components.

Continue to Step 10

1IGNITION COIL CHECKAll OKProblems metOperation

Using the Examiner 180636900, visually check the operation of the coil connected to the cylinder concerned.

In particular, check that the spark is regular

Continue to Step 2The coil spark is not regularContinue to Step 9
2SPARK PLUG CONDITION CHECKAll OKProblems metOperation

Check that the electrode gap for the spark plug concerned is within the permissible limits.

Also check that the electrodes are not worn/broken

Continue to Step 3Spark plug faulty

Replace the spark plug Op. 5510D10

Continue to Step 10

3CHECK ON FUEL PRESSUREAll OKProblems metOperation

Test the fuel pressure Op. 0510C10by turning the ignition ON and waiting for a few seconds. Start the engine normally and after a few seconds turn the ignition off.

Check that the pressure remains at normal values and that it has not fallen by more than 1.5 bar 15 minutes after the engine has been turned off. Dismantle the injector flute complete with all the injectors Op. 1056B60. Place a container under the injector flute.

Continue to Step 6Pressure is too low: constrictions on the supply pipe

Renew or, if necessary, replace the pipe.

Continue to Step 10

Excessive pressure drops after switch-offContinue to Step 4
Low pressure: faults in the fuel pump unit

Replace the fuel pump assembly Op. 1040A70

Continue to Step 10

4CHECK INJECTOR SEALAll OKProblems metOperation

Check that there are no fuel leaks from the injector concerned.

Refit the injector flute Op. 1056B60

Work very carefully and in safe conditions

Continue to Step 5The injector leaks

Replace the injector Op. 1056B70

Continue to Step 10

5REPLACING FUEL PUMPAll OKProblems metOperation
Replace the fuel pump assembly Op. 1040A70Continue to Step 10Fault persistsContinue to Step 10
6INJECTOR ACTIVE DIAGNOSISAll OKProblems metOperation
Carry out active diagnosis on the injector concerned, checking that during activation there is spray from the injector. Refit the injector flute Op. 1056B60Continue to Step 7Injector stuck shut

Replace the injector Op. 1056B60

Continue to Step 10

7CYLINDER COMPRESSION CHECKAll OKProblems metOperation
Carry out the cylinder compression test Op. 0510A10Continue to Step 10Compression insufficient for the cylinder involvedContinue to Step 8
8CHECK ON CAUSE OF INSUFFICIENT COMPRESSIONAll OKProblems metOperation

Carry out R/R on head to check the valve seal

Check the condition of the cylinders/piston rings

Insufficient valve seal

Overhaul the cylinder head Op. 1016E10

Continue to Step 10

Cylinders/piston rings worn

Renew the seal.

Continue to Step 10

9COIL REPLACEMENTAll OKProblems metOperation
Exchange the coil concerned with one from another cylinder Op. 5510C10and check, using the Examiner 1806369000 that the spark is regularContinue to Step 10There is no regular spark

Renew the old coil and replace the engine management control unit Op. 1056B82

Continue to Step 10

10ERROR CANCELLING AND CHECKINGAll OKProblems metOperation

Use a tester to cancel the errors in the control unit.

Road test the vehicle and check that the error does not occur again

Continue to Step 11The fault persists, it is the first or the second time that this Step has been reached and the control unit has not yet been replacedContinue to Step 0
The fault persists, but it is the third time that this step has been reached or the control unit has already been replacedContact Technical Support for further information on the problem
11CORRECT OPERATION CHECKAll OKProblems metOperation
Check that the fault is no longer presentFault persistsSearch for the fault starting from another symptom'

3.2 V6

The diagnostic equipment signals the following error: Misfire in cylinder X

Carry out the procedure for the circuit for the cylinder in which the error was detected

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Check that the ignition circuit is correctly connected and working properly, paying particular attention to:

Continue to Step 1Faults in the electrical circuit

Restore correct connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT. If necessary, replace the faulty components.

Continue to Step 10

1IGNITION COIL CHECKAll OKProblems metOperation

Using the Examiner 180636900, visually check the operation of the coil connected to the cylinder concerned.

In particular, check that the spark is regular

Continue to Step 2The coil spark is not regularContinue to Step 9
2SPARK PLUG CONDITION CHECKAll OKProblems metOperation

Check that the electrode gap for the spark plug concerned is within the permissible limits.

Also check that the electrodes are not worn/broken

Continue to Step 3Spark plug faulty

Replace the spark plug Op. 5510D10

Continue to Step 10

3CHECK ON FUEL PRESSUREAll OKProblems metOperation

Test the fuel pressure Op. 0510C10by turning the ignition ON and waiting for a few seconds. Start the engine normally and after a few seconds turn the ignition off.

Check that the pressure remains at normal values and that it has not fallen by more than 1.5 bar 15 minutes after the engine has been turned off. Dismantle the injector flute complete with all the injectors Op. 1056B60. Place a container under the injector flute.

Continue to Step 6Pressure is too low: constrictions on the supply pipe

Renew or, if necessary, replace the pipe.

Continue to Step 10

Excessive pressure drops after switch-offContinue to Step 4
Low pressure: faults in the fuel pump unit

Replace the fuel pump assembly Op. 1040A70

Continue to Step 10

4CHECK INJECTOR SEALAll OKProblems metOperation

Turn the ignition on and after a few seconds turn it off again.

Check that there are no fuel leaks from the injector concerned.

Refit the injector flute Op. 1056B60

Work very carefully and in safe conditions

Continue to Step 5The injector leaks

Replace the injector Op. 1056B70

Continue to Step 10

5REPLACING FUEL PUMPAll OKProblems metOperation
Replace the fuel pump assembly Op. 1040A70Continue to Step 10Fault persistsContinue to Step 10
6INJECTOR ACTIVE DIAGNOSISAll OKProblems metOperation
Carry out active diagnosis on the injector concerned, checking that during activation there is spray from the injector. Refit the injector flute Op. 1056B60Continue to Step 7Injector stuck shut

Replace the injector Op. 1056B70

Continue to Step 10

7CYLINDER COMPRESSION CHECKAll OKProblems metOperation
Carry out the cylinder compression test Op. 0510A10Continue to Step 10Compression insufficient for the cylinder involvedContinue to Step 8
8CHECK ON CAUSE OF INSUFFICIENT COMPRESSIONAll OKProblems metOperation

Carry out R/R on head to check the valve seal

Check the condition of the cylinders/piston rings

End of diagnosisInsufficient valve seal

Overhaul the cylinder head Op. 1016E10

Continue to Step 10

Cylinders/piston rings worn

Renew the seal.

Continue to Step 10

9COIL REPLACEMENTAll OKProblems metOperation
Exchange the coil concerned with one from another cylinder Op. 5510C10and check, using the Examiner 1806369000 that the spark is regularContinue to Step 10There is no regular spark

Renew the old coil and replace the engine management control unit Op. 1056B82

Continue to Step 10

10ERROR CANCELLING AND CHECKINGAll OKProblems metOperation

Use a tester to cancel the errors in the control unit.

Road test the vehicle and check that the error does not occur again

Continue to Step 11The fault persists, it is the first or the second time that this Step has been reached and the control unit has not yet been replacedContinue to Step 0
The fault persists, but it is the third time that this step has been reached or the control unit has already been replacedContact Technical Support for further information on the problem
11CORRECT OPERATION CHECKAll OKProblems metOperation
Check that the fault is no longer presentFault persists

Parts & tools for this job For 2000 Alfa Romeo 147

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