22 · Diagnostics

Engine idle irregular

Make: Fiat
Model: Stilo Factory Service Manual
Year: 2001–2007
Section: Engine › Engine idle irregular

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Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

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

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	Air filter clogged	Replace the filter element Op. 1048A14
		Continue to Step 1	Faulty in the air intake circuit	Restore 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. 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
			Another error dectected in the control unit	Continue following the instructions for the diagnostic equipment
			Incoherent parameter	Continue following the instructions for the diagnostic equipment
2	CHECK ON PETROL VAPOUR RECOVERY SYSTEM	All OK	Problems met	Operation
	Check the condition and the seal of the pipe between the canister solenoid valve and the intake manifold	Continue to Step 3	Air leaks	Renew the correct seal
		Continue to Step 3	Pipe between solenoid valve and manifold damaged	Replace the pipe
3	CHECK ON PETROL VAPOUR RECOVERY SOLENOID	All OK	Problems met	Operation
	Carry out active diagnosis of solenoid	Continue to Step 5	Faulty solenoid	Continue to Step 4
4	CHECK ON SOLENOID ELECTRICAL CIRCUIT	All OK	Problems met	Operation
	Check supply and earth of petrol vapour recovery solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 5	Solenoid valve faulty	Replace the solenoid valve Op. 1080E28
		Continue to Step 5	Solenoid valve faulty	Restore connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
5	CHECK ON BRAKE SERVO AND PIPE	All OK	Problems met	Operation
	Check the condition of the brake servo vacuum pipes; See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT Check the operation of the single-active valve and the brake servo See Test 3330DA Check operation of brake servo	Continue to Step 6	Brake servo pipe faulty	Replace the pipe
		Continue to Step 6	Brake servo faulty	Replace the brake servo/pump assembly
6	CHECKING FUEL PRESSURE	All OK	Problems met	Operation
1.8 16v 2.4 20v	Check the fuel supply pressureOp. 0510C10	Continue to Step 7	Insufficient fuel pressure: pipe blocked	Eliminate the blockage; if necessary replace the pipes If necessary, replace the actuator
1.8 16v 2.4 20v	Check the fuel supply pressureOp. 0510C10	Continue to Step 7	Insufficient fuel pump: pump faulty	Replace pump assembly Op. 1040A70
1.2 16v 1.6 16v	Check the fuel supply pressureOp. 0510C10	Continue to Step 10	Insufficient fuel pressure: pipe blocked	Eliminate the blockage; if necessary replace the pipes
1.2 16v 1.6 16v	Check the fuel supply pressureOp. 0510C10	Continue to Step 10	Insufficient fuel pump: pump faulty	Replace pump assembly Op. 1040A70
7	Check variable valve timing system manifold	All OK	Problems met	Operation
1.8 16v 2.4 20v	Carry out active diagnosis of variable valve timing	Continue to Step 9	Faulty solenoid	Continue to Step 8
8	CHECK ON TIMING VARIATOR ELECTRICAL CIRCUIT	All OK	Problems met	Operation
1.8 16v 2.4 20v	Check power and earth of variable valve timing system solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 9	Connections not correct	Restore connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
9	CHECKING VARIABLE VALVE TIMING SYSTEM	All OK	Problems met	Operation
1.8 16v 2.4 20v	Check the operation of the variable valve timing system by powering the solenoid of the variator directly. There must be a significant change in engine speed (surging or very irregular idle)	Continue to Step 10	There are no changes in engine speed: timing variator stuck	Replace the phase transformer Op. 1036C40
10	CHECKING TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 11	Timing incorrect	Restore the correct timing
11	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

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Verify: the condition of the air intake circuit condition and correct operation of the air filter	Continue to Step 1	Faulty in the air intake circuit	Restore the air intake circuit
		Continue to Step 1	Air filter clogged	Replace the filter element Op. 1048A14
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 carry out active diagnosis of E.G.R. solenoid	Continue to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Implausible parameters	Continue following the instructions for the diagnostic equipment
			Lack of dialogue with the control unit	Restore the connection between engine management control unit and diagnostic connector See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
			Faulty solenoid	Check wiring continuity See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
			Faulty solenoid	Replace the solenoid valve Op. 1080C74
2	FUEL FILTER CHECK	All OK	Problems met	Operation
	Check the operation of the fuel filter	Continue to Step 3	Presence of water, petrol, paraffin or dirt detected	Clean the tank and pipes and replace the diesel filter cartridge Op. 1044B20
3	CHECKING VALVE CLEARANCES	All OK	Problems met	Operation
	Check that the valve tappet clearance is correct.	Continue to Step 4	Valve clearance incorrect	Adjust the tappets Op. 1036H10
4	CHECKING CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test	Continue to Step 6	Insufficient cylinder compression	Continue to Step 5
5	CHECKING CAUSE OF INSUFFICIENT COMPRESSION	All OK	Problems met	Operation
	Carry out R.R. on head to check the valve seal and check the condition of the cylinders/piston rings	Continue to Step 6	Insufficient valve seal	Overhaul the cylinder head Op. 1016E10
6	CHECKING CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present		Fault persists: control unit defective	Replace engine management control unit Op. 1060G80 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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