2427478 - D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE

Under all conditions
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • the state of the spark plugs and leads;
  • full accelerator pedal travel
  • the condition of air filter
  • the condition of the air intake circuit;
  • absence of obstructions in the catalytic converter
Continue to Step 1Spark plugs dirty or damagedReplace the spark plugs Op.   5510D10 
Cables damagedReplace spark plug leads Op. 5510D14
Insufficient accelerator pedal travelRestore pedal travel
Air intake circuit faultEliminate the problem
Catalyzer obstructedReplace the exhaust manifold Op.   1072C16 
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;
  • parameter plausibiilty
Continue to Step 2'Supply system' error detectedSee table   Z50 
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
Road test the vehicle, reproducing the conditions in which the fault arises, keeping the diagnostic equipment connected.

Check:

  • that there are no faults in the engine management control unit;
  • parameter plausibiilty
Continue to Step 3'Supply system' error detectedSee table   Z50 
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
Insufficient fuel pressure: valve obstructedReplace the tank cap
Insufficient fuel pressure: regulator out of calibrationReplace the pump assembly
Low fuel pressure: defective pumpReplace the pump assembly
Low fuel pressure: clogged filterReplace the pump assembly
4CHECK ON TIMINGAll OKProblems metOperation
Check that the timing is correctContinue 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  )