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: battery earth correctly fixed See E1010 SUPPLY condition of the air intake circuit condition of the spark plugs quality of the fuel check engine wiring earths	Continue to Step 1	Earth fastening not correct	Restore correct fixing
			Air intake circuit fault	Restore the correct operation of the intake circuit
			Spark plugs not the type recommended by the manufacturer	Replace the spark plugs
			Impurities in the fuel	Clean the fuel tank
			Earths faulty	Restore correct fixing
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	Error detected	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Inconsistent parameter	Analyze the factors that have caused this inconsistency.
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: condition of the cable that there are no faults in the engine management control unit; the plausibiilty of the parameters, in particular: rail pressure - rail pressure setting injection times rpm (graphic acquisition of the signal is best) engine temperature	Continue to Step 3	Error detected	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Inconsistent parameter	Anaylze the factors that have caused this inconsistency
3	LOW PRESSURE CIRCUIT CHECK	All OK	Problems met	Operation
	Check that the fuel pressure is correct	Continue to Step 4	Incorrect pressure: obstructions in the fuel delivery pipe	Remove the obstructions in the fuel pipe and, if necessary, replace it
			Pressure not correct: tank insufficiently ventilated	Restsore the tank ventilation
			Pressure not correct: petrol pump damaged or not correctly supplied	Replace fuel pump assembly Op. 1040A70
4	RAIL PRESSURE SENSOR CHECK	All OK	Problems met	Operation
	Check the operation of the rail sensor	Continue to Step 5	Pressure sensor faulty	Replace sensor.
5	PRESSURE REGULATOR CHECK	All OK	Problems met	Operation
	Check that the voltage regulator is working	Continue to Step 6	Pressure regulator faulty	Replace the pressure regulator
6	HIGH PRESSURE PUMP CHECK	All OK	Problems met	Operation
	Check the operation of the high pressure pump	Continue to Step 7	High pressure pump faulty	Replace high pressure pump
7	CHECK ON INJECTORS	All OK	Problems met	Operation
	Check the continuity/insulation of the injector wiring; in particular, make sure that the injector operating signal is present See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 8	No signal, wiring broken	Renew the wiring See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 8	No signal, wiring not broken	Replace engine management control unit
8	IGNITION OPERATION CHECK	All OK	Problems met	Operation
	Check the continuity/insulation of the supply circuit and the coil operation; in particular, make sure that the coil operating signal is present See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 9	No supply/earth	Renew the wiring See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 9	No operating signal	Check the wiring between the coils and the ECU and, if necessary, replace the control unit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
9	PHASE TRANSFORMER CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the phase transformer in active diagnosis	Continue to Step 10	Not working	Using a voltmeter (graphic is best) check the transformer operating signal and, if necessary, replace the transformer See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
10	MODULAR MANIFOLD CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the modular manifold in active diagnosis	Continue to Step 11	Not working	Using a voltmeter (graphic is best) check the modular manifold operating signal and, if necessary, replace the modular manifold solenoid valve See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
11	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 12	Timing not correct	Ensure that the timing is correct
12	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis