Engine not running smoothly / (losing power)

Make: Fiat
Model: Stilo Factory Service Manual
Year: 2001–2007
Section: Engine › Engine not running smoothly / (losing power)

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Fault diagnosisEngine not running smoothly / (losing power)

ENGINE NOT RUNNING SMOOTHLY / (LOSING POWER)

1.2 16v, 1.6 16v, 1.8 16v, 2.4 20v

Under conditions of constant load and speed, there are intermittent decreases in performance, even prolonged

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	First check: the condition of the air filter; the condition of the air intake circuit	Continue to Step 1	Blocked filter	Replace the filter element Op. 1048A14
		Continue to Step 1	Blocked filter	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. Verify: that there are no faults in the engine management control unit the plausibiilty of the parameters	Continue to Step 2	'Fuel system' error appears	See table Z50 MIXTURE STRENGTH ERROR
			'Misfiring' error appears	See table Z53 MISFIRE ERROR
			Incoherent parameter	Continue following the instructions for the diagnostic equipment
			Incoherent 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. Verify: that there are no faults in the engine management control unit the plausibiilty of the parameters	Continue to Step 3	'Fuel system' error appears	See table Z50 MIXTURE STRENGTH ERROR
			Incoherent parameters	See table Z53 MISFIRE ERROR
			Incoherent parameters	Continue following the instructions for the diagnostic equipment
			Incoherent parameters	Continue following the instructions for the diagnostic equipment
3	FUEL PRESSURE ROAD TEST	All OK	Problems met	Operation
	Road test the vehicle and check the fuel supply pressure in the conditions that lead to the anomaly Op. 0510C10	Continue to Step 4	Insufficient fuel presure: pipes obstructed	Remove the blockages and replace the pipes if necessary
		Continue to Step 4	Insufficient fuel pump: pump faulty	Replace the fuel pump assembly Op. 1040A70
4	CHECKING 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'

1.9 JTD 8v

Under conditions of constant load and speed, there are intermittent decreases in performance, even prolonged

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check, in order: that there are no leaks from the fuel system the condition of the air intake circuit for any obstructions in the catalyzer that there is no water in the diesel filter the condition of the air intake circuit	Continue to Step 1	Fuel leaks	Eliminate the water from the diesel
			Faulty in the air intake circuit	Restore the air intake circuit
			Catalyzer obstructed	Replace the catalyzer
			Water in diesel filter	Clean the tank and replace the filter
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket. Verify: that there are no errors in the control unit the plausibiilty of the parameters	Continue to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Implausible parameters	Continue following the instructions for the diagnostic equipment
2	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Road test the vehicle keeping the diagnostic instrument connected Make sure that the conditions in which the problem occurs are reproduced Verify: that there are no errors in the control unit the plausibiilty of the parameters	Continue to Step 3	Error suddenly occurs in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Parameters off the scale	Continue following the instructions for the diagnostic equipment
3	CHECK ON BRAKE PEDAL SWITCH	All OK	Problems met	Operation
	Check that the brake pedal switch is working properly See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT	Continue to Step 4	Brake pedal does not return	Eliminate the cause of the sticking
			Switch faulty	Replace the switch
			Wiring short circuited (intermittently)	Eliminate the cause of the problem See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
4	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present		Fault persists	Search for the fault starting from another symptom'

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Parts & tools for this job For 2001 Fiat Stilo

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