D10 ENGINE IDLE IRREGULAR - Alfa - 166 - eLearn

3308608 - D10 ENGINE IDLE IRREGULAR

The engine is not running smoothly when idling; in particular, it does not maintain a constant, regular value as the load varies (e.g. when electrical devices are switched on, etc.).

1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
	Connect diagnostic equipment (Examiner or other instruments) to the diagnostic socket. Verify: that there are no faults in the engine management control unit the plausibility of all the parameters	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Lack of dialogue with the control unit	Restore the connection between the engine management control unit and the diagnostic connector ( See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT )
2	FUEL FILTER CHECK	All OK	Problems met	Operation
	Check that the fuel filter is working	Continue to Step 3	Presence of water, petrol, paraffin or dirt detected	Clean tank and pipes and replace filter element Op. 1044B20
3	CHECKING AIR CIRCUIT	All OK	Problems met	Operation
	Check, in order: the condition of the air filter the condition and seal of the air supply circuit	Continue to Step 4	Filter dirty or partially blocked	Replace air filter Op. 1048A14
		Continue to Step 4	Circuit component damaged	Replace the component (see Assembly PROCEDURES. 1048A)
4	CHECKING VALVE CLEARANCES	All OK	Problems met	Operation
	Check that the valve tappet clearance is correct. Op. 1036H14	Continue to Step 5	Clearance not correct	Restore the correct valve clearance. Op. 1036H18
5	CHECKING CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 6	Compression values not correct	Restore the correct cylinder compression, for example, by checking the seal of the injectors Op. 1056B70 and cylinders (see OVERHAULING ENGINE, Subassembly 1004)
6	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'