2398744 - D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE

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Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • the condition of air filter
  • the condition of the air intake circuit;
  • no obstructions in the exhaust pipe
Continue to Step 1Air intake circuit faultEliminate the problem, if necessary replacing the filter element Op.   1048A14 
Pipe obstructed Restore the operation of the exhaust pipe
1CHECKING 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 2'Supply system' error detectedContinue according to the instructions for the See table   Z50  MIXTURE STRENGTH ERROR
Another error dectected in the control unitContinue following the instructions for the diagnostic equipment
Inconsistent parameterContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Carry out a road test keeping the diagnostic equipment connected

Check:

  • that there are no faults in the engine management control unit;
  • plausibility of all the parameters
Continue to Step 3'Supply system' error detectedContinue according to the instructions for the See table   Z50  MIXTURE STRENGTH ERROR
Sudden occurrence of another error detectedContinue following the instructions for the diagnostic equipment
Parameters inconsistentContinue following the instructions for the diagnostic equipment
3FUEL PRESSURE ROAD TESTAll OKProblems metOperation
Road test the vehicle and check the fuel supply pressure Op.   0510C10  in the conditions that lead to the anomalyContinue to Step 4Insufficient fuel pressure: pipes obstructedRemove restrictions
Low fuel pressure: defective pumpReplace the pump assembly Op.   1040A70 
4CHECK ON TIMINGAll OKProblems metOperation
Check that the timing is correct Op.   0510A20  Continue to Step 5Timing not correctRestore the correct timing
5CHECK ON CYLINDER COMPRESSIONAll OKProblems metOperation
Carry out the cylinder compression test Op.   0510A10  Continue to Step 7Cylinder compression insufficientContinue to Step 6
6CHECK ON CAUSE OF INSUFFICIENT COMPRESSIONAll OKProblems metOperation
Carry out R/R on head to check the valve sealCheck the condition of the cylinders/piston ringsContinue to Step 7Insufficient valve sealOverhaul the cylinder head
Cylinders/piston rings wornRepair the leak
7CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit faultyReplace control unit Op.   1056B82