22 · Diagnostics

Excessive fuel consumption

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2004
Section: Consumption /leaks/ wear › Excessive fuel consumption

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Fault diagnosisExcessive fuel consumption

EXCESSIVE FUEL CONSUMPTION

1.6 TS, 2.0 TS

The engine appears to running smoothly, but the fuel consumption is higher than previously recorded during the life of the vehicle.

The consumption data in the vehicle technical documentation has been defined during the course of homologation tests in accordance with directive 93/116/CE. These tests simulate an urban cycle and an 'average' extra-urban cycle and therefore may not be indicative as consumption depends very much on the style of driving.

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check the condition of the air filter Check the state of the spark plugs	Continue to Step 1	Filter element dirty or damaged	Replace the filter element Op. 1048A14
		Continue to Step 1	Spark plugs dirty or damaged	Replace the spark plugs Op. 5510D10
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	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 E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
2	CHECK ON INJECTORS	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the injectors	Continue to Step 3	Injector connections faulty	Restore the connection of the injectors with the control unit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 3	Injectors faulty	Replace the injectors Op. 1056B70
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 4	Pressure not correct (too high a pressure is indicative of excessive consumption)	Replace the fuel pump assembly Op. 1040A70
4	CHECKING AIR CIRCUIT	All OK	Problems met	Operation
	Check the condition and seal of the air supply circuit	Continue to Step 5	Circuit component damaged	Replace the component
5	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists

1.9 JTD 16V

The engine appears to running smoothly, but the fuel consumption is higher than previously recorded during the life of the vehicle.

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check the conditions: of the air filter; of the fuel filter. Check the exhaust circuit, with particular attention to any blockages in the pipes	Continue to Step 1	Filter element dirty or damaged	Replace the filter element Op. 1048A14
			Fuel filter dirty	Replace the filter element Op. 1044B10
			Exhausts obstructed	Replace the complete exhaust pipe Op. 1076B12
			Exhaust system obstructed	Replace the defective system component
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the Examiner diagnostic equipment to the diagnostic connector and check the engine conntrol node: in error mode that there are no faults; in parameters ambient 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
2	HIGH PRESSURE CHECK	All OK	Problems met	Operation
	Check the fuel supply circuit, high pressure side: See Test 1060D Check high pressure fuel circuit	Continue to Step 4	Pressure not correct: pressure regulator faulty	Replace the pressure regulator Op. 1060E50
			Pressure not correct: injector manifold faulty	Replace the manifold Op. 1060F30
			Pressure not correct: injectors faulty	Replace the injectors Op. 1060F10
			Pressure not correct: pipe from pump to manifold faulty	Replace the pipe
			Pressure not correct: pipe from manifold to injectors faulty	Replace the pipe
3	LOW PRESSURE CHECK	All OK	Problems met	Operation
	Check the fuel supply circuit, low pressure side: See Test 1060A Low return fuel pressure circuit check See Test 1060B Low fuel pressure supply circuit check	Continue to Step 4	Pressure not correct: fuel filter faulty	Replace the fuel filter Op. 1048A10
			Pressure not correct: electric pump faulty	Replace the electric pump Op. 1040A70
			Pressure not correct: return manifold faulty	Replace the manifold Op. 1060F50
			Pressure not correct: fuel return pipes faulty	Replace the pipes concerned
4	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis

All versions

The engine appears to running smoothly, but the fuel consumption is higher than previously recorded during the life of the vehicle.

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check if there is service information on the subject The condition of the air filter; Check the exhaust circuit, paying special attention to any obstructions in the pipes	Continue to Step 1	Filter element dirty or damaged	Replace the filter element Op. 1048A14
			Exhausts obstructed	Replace the complete exhaust pipe Op. 1076B12
			Exhaust silencers blocked	Replace the silencers
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the Examiner diagnostic equipment to the diagnostic connector and check the engine management control unit: in error mode that there are no faults; in parameters ambient the plausibility of all the parameters, in particular: engine temperature, advance/possible advance for detonation, injection times, air mass, fuel consumption	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Unreliable parameters	Continue following the instructions for the diagnostic equipment, analyzing the causes that have led to the implausibility
2	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment, check that the upstream and downstream Lambda sensors are working properly	Continue to Step 3	Irregular operation	Replace the defective Lambda sensor
3	PHASE TRANSFORMER CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the phase transformer in active diagnosis	Continue to Step 4	Not working	Using a voltmeter (graphic is best) check the transformer operating signal and, if necessary, replace the transformer
4	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the valve gear timing is correct	Continue to Step 5	Timing not correct	Restore the correct timing Op. 1032B14
5	MODULAR MANIFOLD CHECK IN ACTIVE DIAGNOSIS	All OK	Problems met	Operation
	Check the operation of the modular manifold in active diagnosis	Continue to Step 6	Not working	Using a voltmeter (graphic is best) check the modular manifold operating signal and, if necessary, replace the modular manifold solenoid valve
6	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis

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Parts & tools for this job For 2000 Alfa Romeo 147

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