125000497 - D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE

Engine judders when car is in motion and is not efficient.
Results of the tests
0PRELIMINARY CHECKSAll OKProblems encounteredOperation

First, check:

  • status of spark plugs and leads;
  • complete accelerator pedal travel;
  • condition of the air filter;
  • the condition of the air intake circuit;
  • no obstructions at the catalyzer
Move on to Step 1Spark plugs dirty or damagedReplace the spark plugs    Op. 5510D10 SPARK PLUGS - R+R
Leads damagedReplace spark plug leads
Accelerator pedal travel insufficientRestore the pedal travel
Air intake circuit faultyEliminate the fault
Catalytic converter obstructedReplace the exhaust manifold    Op. 1072C12 EXHAUST MANIFOLD - R R
1CHECK USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Connect the diagnostic test equipment (Examiner or other instruments) to the tester input.

Check:

  • that there are no faults in the engine management control unit;
  • parameter plausibility
Move on to Step 2"Fuel system" error detectedContinue following the instructions in the Table    See table Z50 MIXTURE STRENGTH ERROR
Another error detected in the control unitContinue following the instructions for the diagnostic equipment
Parameter not consistentContinue following the instructions for the diagnostic equipment
2ROAD TEST USING DIAGNOSTIC EQUIPMENTAll OKProblems encounteredOperation
Carry out a road test reproducing the conditions in which the fault occurs, keeping the diagnostic equipment connected.

Check:

  • that there are no faults in the engine management control unit;
  • parameter plausibility
Move on to Step 3"Fuel system" error detectedContinue following the instructions in the Table Z50 ERRORE TITOLO MISCELA
The sudden onset of another error is detectedContinue following the instructions for the diagnostic equipment
Parameters not consistentContinue following the instructions for the diagnostic equipment
3FUEL PRESSURE ROAD TESTAll OKProblems encounteredOperation
Carry out a road test and check the fuel supply pressure in the conditions in which the problem occurs    Op. 0510C10 FUEL SYSTEM - CHECK DELIVERY PRESSUREMove on to Step 4Fuel pressure too low: pipes obstructedEliminate the constrictions
Fuel pressure too low: valve obstructedReplace the fuel cap    Op. 1040A40 PLUG FOR FUEL FILLER PIPE - R + R
Fuel pressure too low: regulator blockedReplace the fuel pump assembly    Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GUAGE CONTROL - R + R
Fuel pressure too low: pump defectiveReplace the fuel pump assembly    Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GUAGE CONTROL - R + R
Fuel pressure too low: filter blockedReplace the fuel pump assembly    Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GUAGE CONTROL - R + R
4PHASE TRANSFORMER SOLENOID VALVE CHECKAll OKProblems encounteredOperation
Carry out active diagnosis of the variable valve timing solenoid valveMove on to Step 6Solenoid valve not workingMove on to Step 5
5PHASE TRANSFORMER ELECTRICAL CIRCUIT CHECKAll OKProblems encounteredOperation
Check the supply and earth for the variable valve timing solenoid valve    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENTMove on to Step 6Phase transformer faultyReplace the phase transformer    Op. 1036C40 TIMING VARIATOR ON INLET CAMSHAFT IN CYLINDER HEAD R + R WITH SHAFT REMOVED
Connections not correctRepair the connections    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
6PHASE TRANSFORMER CHECKAll OKProblems encounteredOperation
Check the operation of the vvt (hydraulic actuator) by carrying out Test 1056OA    See Test 1056 PETROL INJECTION SYSTEMMove on to Step 7There are no speed variations: phase transformer stuckReplace the phase transformer    Op. 1036C40 TIMING VARIATOR ON INLET CAMSHAFT IN CYLINDER HEAD R + R WITH SHAFT REMOVED
7TIMING CHECKAll OKProblems encounteredOperation
Check that the valve gear timing is correctMove on to Step 8Valve gear timing not correctRestore the correct valve gear timing    Op. 1032B10 TOOTHED TIMING BELT - R + R FOR TIMING ADJUSTMENT OR REPLACEMENT
8CYLINDER COMPRESSION CHECKAll OKProblems encounteredOperation
Carry out the cylinder compression check    Op. 0510A10 CYLINDER COMPRESSION - CHECK FOR LOOSE SPARK PLUGS OR INJECTORSMove on to Step 10Cylinder compression insufficientMove on to Step 9
9VALVE SEAL CHECKAll OKProblems encounteredOperation
R/R head for valve leakage testCheck condition of cylinders/piston ringsMove on to Step 10Valve seal insufficientOverhaul the head    Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
Cylinders/piston rings wornRestore the seal
10CHECK ON CORRECT OPERATIONAll OKProblems encounteredOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit defectiveReplace the control unit Op. 1056B82 CENTRALINA (UNICA) DELL''IMPIANTO INIEZIONE/ACCENSIONE - S.R.