D21 ENGINE CUTS OUT WHILST DRIVING - Alfa - 156 - eLearn

3233020 - D21 ENGINE CUTS OUT WHILST DRIVING

The engine cuts out suddenly whilst driving. Later, after starting normally, it works again

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: that there is fuel in the tank the engine wiring is properly connected to earth battery earth correctly fixed correct fixing of positive battery terminal and that all leads are connected no water in the fuel filter	Continue to Step 1	No fuel	Introduce fuel
			Fastenings slack or oxidized	Re-attach correctly
			Presence of water in the fuel filter	Clean the tank and pipes and replace the filter element
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment to the diagnostic socket. Check: for errors in the control unit	Continue to Step 2	An error is detected in the control unit	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 errors in the control unit;	Continue to Step 3	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
3	INJECTOR HIGH PRESSURE CHECK	All OK	Problems met	Operation
	Check, as described in the test See Test 1060C Check high pressure fuel circuit , that diesel leaks from the injector recirculation connections are small and about the same as one another.	Continue to Step 4	Consistent leak from one injector	Replace the injector
4	HIGH PRESSURE CHECK	All OK	Problems met	Operation
	Connect the diagnostic equipment to the diagnostic socket. Check as described in the test See Test 1060D Check high pressure fuel circuit that the diesel pressure parameter is correct	Continue to Step 12	Pressure not correct	Continue to Step 5
5	CHECK ON RETURN LOW PRESSURE	All OK	Problems met	Operation
	Check as described in the test See Test 1060A Check low pressure fuel circuit that the pressure in the return pipe to the tank is under 1 bar	Continue to Step 6	Pressure above maximum limit: return pipe to tank blocked	Repair the pipe; if necessary replace it
6	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Check as described in the test See Test 1060B Check low pressure fuel circuit that the diesel pressure between filter and pressure pump is between 2 and 3 bar	Continue to Step 12	Pressure below minimum limit or above maximum limit	Continue to Step 7
7	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Choke the return pipe from the pressure regulating valve and repeat the test See Test 1060B Check low pressure fuel circuit with the pipe choked, checking that the pressure at the filter outlet is below 2 bar	Continue to Step 8	Pressure rises to 5 bar: blocked pressure regulation valve on filter support	Replace the valve Op. 1044B16
8	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Check that the difference in pressure upstream and downstream of the filter is less than 1 bar	Continue to Step 9	Difference in pressure greater than 1 bar	Replace the diesel filter cartridge Op. 1044B20
9	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Check that the supply pump pressure at the filter inlet is over 2.2 bar	Continue to Step 12	Pressure below 2.2 bar	Continue to Step 10
10	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Measure the difference in pressure between electric pump outlet and filter inlet, checking that it is less than 0.3 bar	Continue to Step 11	Difference in pressure greater than 0.3 bar	Replace the pipe
11	LOW SUPPLY PRESSURE CHECK	All OK	Problems met	Operation
	Check as described in the test See Test 1040AA Check supply voltage and absorption current that the pump's supply voltage is 12V and that the absorbed current is between 2 and 10 amps.	Continue to Step 12	Voltage < 12 V	Check electric wiring See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
			Current > 10 Amp: pump defective	Replace the fuel pump assembly Op. 1040A70
			Current < 2 Amp.: pump blocked	Replace the fuel pump assembly Op. 1040A70 and clean the fuel tank
12	CORRECT OPERATION CHECK	All OK	Problems met	Operation
	Replace the DRV pressure regulator and check that the fault is no longer present	End of diagnosis	Fault persists	Continue to Step 13
13	CORRECT OPERATION CHECK	All OK	Problems met	Operation
	Replace the pressure pump and check that the fault is no longer present	End of diagnosis	Fault persists	Contact Technical Service for further information on the problem