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Fiat Multipla Factory Service Manual (1998-2010)22 · Fault diagnosis
22 · Diagnostics

Engine not running smoothly / (hesistant)

Make
Fiat
Model
Multipla Factory Service Manual
Year
1998–2010
Section
Engine › Engine not running smoothly / (hesistant)
Fault diagnosisEngine not running smoothly / (hesistant)

ENGINE NOT RUNNING SMOOTHLY / (HESISTANT)

1.6 16v

The engine does not run smoothly in all conditions (load, speed, etc.).

In particular, it "hesitates", i.e. there is a lack of or delayed response from the accelerator pedal

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • that there is no water, other fluid or dirt in the fuel tank
  • the state of the spark plugs and leads
  • engine wiring earth correctly fixed
  • battery earth correctly fixed
  • positive lead between battery and alternator correctly fixed
Continue to Step 1Presence of dirt in the fuel tankClean the fuel tank Op. 1040A24
Spark plugs dirty or damagedClean or replace the spark plugs Op. 5510D10
Spark plug leads damagedReplace the spark plug leads Op. 5510D14
Earth leads incorrectly fixedRestore battery earth lead Op. 5530B22
Battery positive earth incorrectly fixedRestore battery positive lead Op. 5530B26
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket

Check:

  • that there are no faults in the engine management control unit
  • plausibility of all the parameters
Continue to Step 2An error is detected in the control unitContinue according to the instructions for the diagnostic equipment
Lack of dialogue with the control unitRestore the connection between the engine management control unit and the diagnostic connector ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT).
2ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of:

  • vapour recovery solenoid valve
  • electro-injector
  • coils
Continue to Step 3Faulty vapour recovery solenoid connectionRestore the connection of the solenoid valve with the control unit ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT)
Faulty vapour recovery solenoidReplace the solenoid valve Op. 1080E28
Injector connections faultyRestore the connection of the injectors with the control unit, ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT)
Ignition coils faultyReplace the injectors Op. 1056B70
Ignition coils faultyRestore the connection for the coils with the control unit, See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
Ignition coils faultyReplace the ignition coils Op. 5510C14
3FUEL PRESSURE CHECKAll OKProblems metOperation
Check the fuel supply pressure Op. 0510C10Continue to Step 4Pressure not correctReplace the fuel pump assembly Op. 1040A70
4LAMBDA SENSOR CHECKAll OKProblems metOperation
Check that the Lambda sensor is working properlyContinue to Step 5Lambda sensor not working properlyReplace the Lambda sensor Op. 1080B60
5AIR CIRCUIT CHECKAll OKProblems metOperation

Check:

  • the condition and seal of the air supply circuit, and the filter in particular
Continue to Step 6Circuit component damagedReplace the component (see Assembly 1048A)
Air filter incorrectly fittedRefit the air filter correctly Op. 1048A14
Air cleaner dirty or partially blockedReplace the air filter Op. 1048A14
6CYLINDER COMPRESSION CHECKAll OKProblems metOperation
Carry out the cylinder compression test Op. 0510A10Continue to Step 7Compression values not correctRestore the correct cylinder compression, e.g by checking the seal of the injectors Op. 1056B70and the cylinders if necessary
7CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persistsSearch for the fault starting from another symptom'

Parts & tools for this job For 1998 Fiat Multipla

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