2888334 - D03 ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

The engine does not run smoothly in all conditions (load, speed, etc.). In particular, it is irregular with short but frequent flat spots
Results of the tests
0PRELIMINARY CHECKSAll OKProblems encounteredOperation

First, check:

  • condition of the air filter
  • status of spark plugs and leads
  • wiring on engine correctly fastened to earth
  • battery correctly fastened to earth;
  • correct fastening of positive lead between battery and alternator
Move on to Step 1 1Filter element dirty or damagedReplace the filter element Op.     Op. 1048A14 ELEMENTO FILTRANTE DEL FILTRO ARIA - SOST.
Air filter not correctly fittedRefit air filter correctly Op.     Op. 1048A14 ELEMENTO FILTRANTE DEL FILTRO ARIA - SOST.
Spark plugs dirty or damagedClean or replace the spark plugs Op.     Op. 5510D10 CANDELE ACCENSIONE MOTORE - S.R.
Spark plug leads damagedReplace spark plug leads Op.     Op. 5510D14 FASCIO CAVI CANDELE - S.R.
Earth leads fastening not correctRestore battery earth lead Op.     Op. 5530B22 CAVO DI MASSA BATTERIA - S.R.
Positive battery lead fastenings not correctRestore the positive battery lead Op.     Op. 5530B26 CAVO TRA BATTERIA E MOTORINO DI AVVIAMENTO - S.R.
1CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the diagnostic test equipment (Examiner or other instruments) to the diagnostic socket.

Check:

  • that there are no faults in the engine management control unit
  • the plausibility of all the parameters
Move on to Step 2 1Error detected in the control unitContinue according to the diagnostic equipment instructions
No communication with the control unitRestore connection between engine management control unit and diagnostic connector See    Vedere E5030 GESTIONE ELETTRONICA MOTORI BENZINA
2INJECTOR CHECKAll OKProblems encounteredOperation
With the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the injectorsMove on to Step 3 1Injector connection faultyRepair the connection for the injectors with the control unit, See    Vedere E5030 GESTIONE ELETTRONICA MOTORI BENZINA
Injectors faultyReplace injectors Op.     Op. 1056B70 ELETTROINIETTORE (UNO) - S.R. A TUBO COLLETTORE COMBUSTIBILE STACCATO - COMPRENDE LA SOST. DELLA GUARNIZIONE
3FUEL PRESSURE CHECKAll OKProblems encounteredOperation
Check the fuel supply pressure Op.     Op. 0510C10 IMPIANTO DI ALIMENTAZIONE CARBURANTE - VERIFICA PRESSIONE DI MANDATAMove on to Step 4 1Pressure not correctReplace the fuel pump assembly Op.     Op. 1040A70 COMPLESSIVO POMPA IMMERSA COMPLETA DI COMANDO INDICATORE DI LIVELLO - S.R.
4CYLINDER COMPRESSION CHECKAll OKProblems encounteredOperation
Carry out the cylinder compression test Op.     Op. 0510A10 COMPRESSIONE CILINDRI - VERIFICA A CANDELE O INIETTORI STACCATIMove on to Step 5 1Compressor values not correctRestore the correct cylinder compression, checking the injector seal in particular
5CHECK ACCELERATORAll OKProblems encounteredOperation

Check the accelerator cables, in particular, make sure of

  • cable condition
  • cable slides properly in sheath
  • sheath correctly fastened
Move on to Step 6 1Accelerator cable faultRepair accelerator cable Op.     Op. 1068A30 POTENZIOMETRO SU PEDALE ACCELERATORE - S.R.
6CHECK ON CORRECT OPERATIONAll OKProblems encounteredOperation
Check that the fault is no longer presentEnd of diagnosisFault persists