D03 ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION) - Alfa - 156 - eLearn

3233016 - D03 ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

The engine does not run smoothly in all conditions (load, speed, etc.).In particular, there are brief, but intense 'flat spots'

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: condition of air filter battery earth correctly fixed See E1010 SUPPLY	Continue to Step 1	Filter element dirty, damaged or incorrectly fitted	Replace or refit filter element correctly Op. 1048A14
		Continue to Step 1	Earth fastening not correct	Renew the wiring
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	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 detected	See table Z50 MIXTURE STRENGTH ERROR
			'Upstream lambda sensor' error detected	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			Another error dectected in the control unit	Continue following the instructions for the diagnostic equipment
			Inconsistent parameter	Continue following the instructions for the diagnostic equipment
2	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	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; plausibility of all the parameters	Continue to Step 3	'Supply system' error detected	See table Z50 MIXTURE STRENGTH ERROR
			'Upstream lambda sensor' error detected	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			Sudden occurrence of another error in the control unit detected	Continue following the instructions for the diagnostic equipment
			Inconsistent parameter	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check, if necessary on the road (to reproduce the conditions in which the fault arises), the fuel supply pressure Op. 0510C10	Continue to Step 4	Pressure not correct: obstructions in fuel delivery pipe	Remove the obstructions in the fuel pipe, and if necessary replace it
		Continue to Step 4	Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
4	CHECK AIR CONDITIONING SYSTEM	All OK	Problems met	Operation
	Road test the vehicle and check whether the fault is affected by whether or not the air conditioner is switched on	Continue to Step 5	Fault present only with the air conditioner on	See table L10 CLIMATE CONTROL NOT COOLING
5	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists: control unit faulty	Replace control unit Op. 1056B82