Engine not running smoothly / (losing power)

Make: Fiat
Model: Croma Factory Service Manual
Year: 2005–2010
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)

1.8, 2.2

Prolonged performance reductions occur under constant load and speed conditions.

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Results of the tests
	First, check: status of spark plugs and leads; condition of the air filter; the condition of the air intake circuit; no obstructions at the catalyzer	Move on to Step 1	Spark plugs dirty or damaged	Replace the spark plugs Op. Op. 5510D10 SPARK PLUGS - R+R
			Spark plug leads damaged	Replace spark plug leads
			Air intake circuit faulty	Eliminate the fault
			Catalytic converter obstructed	Replace the exhaust manifold Op. Op. 1072C16 EXHAUST MANIFOLD WITH CATALYTIC CONVERTER - R.R.
1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Connect the diagnostic test equipment (Examiner or other instruments) to the tester input. Check: that there are no faults in the engine management control unit; parameter plausibility	Move on to Step 2	"Fuel system" error detected	See table Z50 ERRORE TITOLO MISCELA
			"Misfire" error detected	See table Z53 ERRORE MANCATE ACCENSIONI
			Another error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameter not consistent	Continue following the instructions for the diagnostic equipment
2	ROAD TEST USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Carry out a road test reproducing the conditions in which the fault occurs, keeping the diagnostic equipment connected. Check: that there are no faults in the engine management control unit; parameter plausibility	Move on to Step 3	"Fuel system" error detected	See table Z50 ERRORE TITOLO MISCELA
			"Misfire" error detected	See table Z53 ERRORE MANCATE ACCENSIONI
			Another error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameter not consistent	Continue following the instructions for the diagnostic equipment
3	FUEL PRESSURE ROAD TEST	All OK	Problems encountered	Operation
	Carry out a road test and check the fuel supply pressure Op. Op. 0510C10 FUEL SYSTEM - CHECK DELIVERY PRESSURE under the conditions in which the fault occurs	Move on to Step 4	Fuel pressure too low: pipes obstructed	Eliminate the constrictions
			Fuel pressure too low: valve obstructed	Replace the fuel cap Op. Op. 1040A40 PLUG FOR FUEL FILLER PIPE - R + R
			Fuel pressure too low: regulator blocked	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
			Fuel pressure too low: pump defective	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
			Fuel pressure too low: filter blocked	Replace the pump assembly Op. Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
4	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present		The fault persists: control unit defective	Replace the control unit Op. Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R Search for the fault starting from another symptom

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Parts & tools for this job For 2005 Fiat Croma

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