3022583 - D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE

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Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Check, in order:

  • the condition of the air intake circuit
  • no faults in the air filter;
  • seal of the diesel pipes;
  • accelerator pedal travel;
  • absence of obstructions in the catalytic converter
Continue to Step 1Fault in air intake circuitRepair the air intake circuit
Air filter blockedReplace the filter element Op.   1048A14 
Leaks from the diesel pipesEliminate the leaks
Accelerator pedal travel incompleteEliminate the cause of the problem
Exhaust system obstructedReplace the defective system component
1CHECK TURBOCHARGER ADJUSTMENTAll OKProblems metOperation
With the diagnostic equipment, carry out active diagnosis on the turbocharger regulating solenoidCheck the operation of the variable geometry control actuator See Test   1064BC  Variable geometry turbocharger actuator leakage test Check the operation of the turbocharger as described in the Test See Test   1064BA  Check the supercharging pressure Continue to Step 2Solenoid not workingCheck the continuity of the wiring See   E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT and if necessary replace the solenoid valve (see in Op. 1064A28
Actuator does not work correctly Check the condition of the vacuum circuit and, if necessary, replace the damaged components
Turbocharger faultyReplace the turbocharger
2CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket

Check:

  • for errors in the control unit
  • plausibility of parameters;
  • carry out active diagnosis of E.G.R. solenoid
Continue to Step 3An error is detected in the control unitContinue following the instructions for the diagnostic equipment
Unreliable parametersContinue following the instructions for the diagnostic equipment
E.G.R. solenoid not workingCheck wiring continuity See   E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT
E.G.R. solenoid not workingReplace the solenoid valve Op.   1080C74 
3ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Road test the vehicle keeping the diagnostic instrument connected.
Make sure that the conditions in which the problem occurs are reproduced

Check:

  • for errors in the control unit
  • plausibility of all the parameters
Continue to Step 4Errors suddenly occur in the control unitContinue following the instructions for the diagnostic equipment
Parameters off scaleContinue following the instructions for the diagnostic equipment
Lack of dialogue with the control unitRestore the connection between engine management control unit and diagnostic connector See   E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT
4CHECK ON BRAKE PEDAL SWITCHAll OKProblems metOperation
Check that the brake pedal switch is working properlyContinue to Step 5Brake pedal does not returnEliminate the cause of the sticking
Switch stuck in closed positionReplace the switch Op.   1060G38 
Wiring short circuitedRestore the correct connection
5HIGH PRESSURE CHECKAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socketCheck as described in test 1060D that the diesel pressure parameter is correctContinue to Step 13Pressure not correctContinue to Step 6
6CHECK ON RETURN LOW PRESSUREAll OKProblems metOperation
Check as described in the test 1060A that the pressure in the return pipe to the tank is under 1 barContinue to Step 7Pressure above maximum limit: return pipe to tank blockedRepair the pipe, if necessary, replace it.
7CHECK ON RETURN LOW PRESSUREAll OKProblems metOperation
LOW SUPPLY PRESSURE CHECK See Test   1060B  Low fuel pressure supply circuit check Continue to Step 13Pressure below minimum limit or above maximum valueContinue to Step 8
8LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Choke the return pipe and repeat test 1060B with the pipe choked, checking that the pressure at the filter outlet remains below 2 bar See Test   1060B  Low fuel pressure supply circuit check Continue to Step 9Pressure rises to 5 bar: blocked pressure regulation valve on filter supportReplace the valve Op.   1044B16 
9CHECK DELIVERY LOW PRESSUREAll OKProblems metOperation
Check that the difference in pressure upstream and downstream of the filter is less than 1 barContinue to Step 10Difference in pressure greater than 1 barReplace the fuel filter cartridge Op.   1044B20 
10LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Check that the pressure downstream of the supply pump is over 2.2 barContinue to Step 13Pressure below 2 barContinue to Step 11
11LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Measure the difference in pressure between the electric pump outlet and filter inlet, checking that it is less than 0.3 barContinue to Step 12Difference in pressure greater than 0.3 barReplace the pipe
12LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Check that the pump supply voltage is 12 V and that the absorbed current is between 2 and 10 amp. See Test   1040AA  Check supply voltage and absorption current Continue to Step 13Voltage < 12 VCheck electric wiring See   E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT
Current > 10 Amp: pump defectiveReplace the fuel pump assembly Op.   1040A70 
Current < 2 Amp.: pump blockedReplace the fuel pump assembly Op.   1040A70  and clean the fuel tank
13CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Replace the DRV pressure regulating valve and check that the fault is no longer presentFault persistsContinue to Step 14
14CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Replace the pressure pump and check that the fault is no longer presentFault persistsContinue to Step 15
15CHECK ON TIMINGAll OKProblems metOperation
Check that the timing is correctContinue to Step 16Timing not correctRestore the correct timing Op. 1032B14
16VALVE CLEARANCE CHECKAll OKProblems metOperation
Check that the valve tappet clearance is correct.Continue to Step 17Valve clearance not correctAdjust the tappets Op.   1036H10 
17CHECK ON CYLINDER COMPRESSIONAll OKProblems metOperation
Carry out the cylinder compression testContinue to Step 19Cylinder compression insufficientContinue to Step 18
19CHECKING CAUSE OF INSUFFICIENT COMPRESSIONAll OKProblems metOperation
Carry out R.R. on head to check the valve seal and check the condition of the cylinders/piston ringsContinue to Step 20Insufficient valve sealOverhaul the cylinder head Op.   1016E10 
19CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer present End of diagnosisFault persists