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Fiat Stilo Factory Service Manual (2001-2007)22 · Fault diagnosis
22 · Diagnostics

Engine not running smoothly / (hesistant)

Make
Fiat
Model
Stilo Factory Service Manual
Year
2001–2007
Section
Engine › Engine not running smoothly / (hesistant)
Fault diagnosisEngine not running smoothly / (hesistant)

ENGINE NOT RUNNING SMOOTHLY / (HESISTANT)

1.2 16v, 1.6 16v, 1.8 16v, 2.4 20v

There are decreases in performance, possibly prolonged, during acceleration

Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

First check:

  • the condition of the air intake circuit
Continue to Step 1Air intake circuit checkRestore correct operation of the intake circuit
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

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

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 2'Fuel system' error appearsSee table Z50 MIXTURE STRENGTH ERROR
'Fuel system' error appearsContinue following the instructions for the diagnostic equipment
'Fuel system' error appearsContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation

Road test the vehicle, reproducing the conditions under which the fault arises, keeping the diagnostic equipment connected

Verify:

  • that there are no faults in the engine management control unit
  • the plausibiilty of the parameters
Continue to Step 3Error arises suddenly in the control unitContinue following the instructions for the diagnostic equipment
Error arises suddenly in the control unitContinue following the instructions for the diagnostic equipment
3CHECKING FUEL PRESSUREAll OKProblems metOperation

Carry out a road test, reproducing the conditions in which the fault arises. with the pipe constricted check that the filter outlet pressure remains below 2 bar.

Check the fuel supply pressureOp. 0510C10

Continue to Step 4Incorrect pressure: obstructions in the fuel delivery pipeRemove the obstructions in the fuel pipe, and if necessary replace it
Incorrect pressure: obstructions in the fuel delivery pipeRestore tank ventilation
Incorrect pressure: obstructions in the fuel delivery pipeReplace fuel pump assembly Op. 1040A70
4CHECKING CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentFault persists: control unit defective

Replace engine management control unit Op. 1056B82

Search for the fault starting from another symptom'

Parts & tools for this job For 2001 Fiat Stilo

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