Engine not running smoothly / (hesistant)

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2004
Section: Engine › Engine not running smoothly / (hesistant)

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Fault diagnosisEngine not running smoothly / (hesistant)

ENGINE NOT RUNNING SMOOTHLY / (HESISTANT)

1.6 TS, 2.0 TS

There are decreases in performance, possibly prolonged, during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the state of the spark plugs and leads; the condition of the air intake circuit	Continue to Step 1	Spark plugs dirty or damaged	Replace the spark plugs Op. 5510D10
			Spark plug leads damaged	Replace the spark plug leads
			Air intake circuit fault	Eliminate the problem
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
			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	Error arises suddenly in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Inconsistent parameter	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Carry out a road test, reproducing the conditions in which the fault arises. Check the fuel supply pressure Op. 0510C10	Continue to Step 4	Incorrect pressure: obstructions in the fuel delivery pipe	Remove the obstructions in the fuel pipe; if necessary replace it Op. 1040B30
			Pressure not correct: tank insufficiently ventilated	Restsore the tank ventilation
			Pressure not correct: fuel pump electrical circuit broken	Repair fuel pump electrical circuit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
			Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
4	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present		Fault persists: control unit defective	Replace control unit Op. 1056B82 Search for the fault starting from another symptom'

All versions

There are decreases in performance, possibly prolonged, during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: if there is service information on the subject the condition of the air intake circuit spark plugs	Continue to Step 1	Air intake circuit fault	Restore the correct operation of the intake circuit
		Continue to Step 1	Spark plugs not the type recommended by the manufacturer	Replace the spark plugs
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	There are errors	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Inconsistent parameter	Continue following the instructions for the diagnostic equipment and analyse the factors that could cause these inconsistencies.
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; the plausibility of the parameters, in particular: rail pressure - rail pressure setting, air mass, engine temperature, upstream Lambda sensor voltage.	Continue to Step 3	Error arises suddenly in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Inconsistent parameter	Continue following the instructions for the diagnostic equipment and analyse the factors that could cause these inconsistencies.
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; 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	PHASE TRANSFORMER CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the phase transformer in active diagnosis	Continue to Step 8	Not working	Using a voltmeter (graphic is best) check the transformer operating signal and, if necessary, replace the transformer
9	MODULAR MANIFOLD CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the modular manifold in active diagnosis	Continue to Step 10	Not working	Using a voltmeter (graphic is best) check the modular manifold operating signal and, if necessary, replace the modular manifold solenoid valve
10	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 11	No supply/earth	Renew the wiring See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 11	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
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

3.2 V6

There are decreases in performance, possibly prolonged, during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the condition of the air intake circuit	Continue to Step 1	Air intake circuit fault	Restore the correct operation of the intake circuit
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	Continue according to the instructions in See table Z50 MIXTURE STRENGTH 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	Error arises suddenly in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Inconsistent parameter	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Carry out a road test, reproducing the conditions in which the fault arises. Check the fuel supply pressure Op. 0510C10	Continue to Step 4	Incorrect pressure: obstructions in the fuel delivery pipe	Remove the obstructions in the fuel pipe; if necessary replace it
			Pressure not correct: tank insufficiently ventilated	Restsore the tank ventilation
			Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
4	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 engine management control unit Op. 1056B82

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Parts & tools for this job For 2000 Alfa Romeo 147

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