22 · Diagnostics

Engine idle irregular

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2004
Section: Engine › Engine idle irregular

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Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

1.6 TS, 2.0 TS

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 filter the condition of the air intake circuit	Continue to Step 1	Spark plugs dirty or defective	Replace the spark plugs Op. 5510D10
			Leads defective	Replace the spark plug leads
			Air filter blocked	Replace the filter element Op. 1048A14
			Fault in air intake circuit	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	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	IDLE ACTUATOR CHECK	All OK	Problems met	Operation
	Check that the system carries out the correct idle learning procedure	Continue to Step 3	Irregular idling	Carry out the idle learning procedure correctly
3	PETROL VAPOUR RECOVERY SYSTEM CHECK	All OK	Problems met	Operation
	Check the condition and seal of the petrol vapour recovery pipes	Continue to Step 4	Air seepage	Restore the correct seal
			Pipe between filter and intermediate coupling broken	Replace the pipe Op. 1080E61
			Pipe between intermediate coupling and solenoid valve 1 Restore the correct seal	Replace the pipe Op. 1080E63
4	PETROL VAPOUR RECOVERY SOLENOID VALVE CHECK	All OK	Problems met	Operation
	Carry out active diagnosis of solenoid	Continue to Step 6	Solenoid not working	Continue to Step 5
5	SOLENOID VALVE ELECTRICAL CIRCUIT CHECK	All OK	Problems met	Operation
	Check supply and earth of petrol vapour recovery solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 6	Solenoid valve faulty	Replace the solenoid valve Op. 1080E28
		Continue to Step 6	Connections not correct	Restore the connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
6	BRAKE SERVO AND PIPE CHECK	All OK	Problems met	Operation
	Check condition of: brake servo vacuum pipes; brake servo	Continue to Step 7	Brake servo pipe defective	Replace the pipe Op. 3330D26
	Check condition of: brake servo vacuum pipes; brake servo	Continue to Step 7	Brake servo defective	Replace the brake servo/pump assembly Op. 3330D02
7	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 8	Insufficient fuel pressure: pipe obstructed	Eliminate the blockage; if necessary replace the pipe Op. 1040B30
			Low fuel pressure: clogged filter	Replace the pump assembly Op. 1040A70
			Insufficient fuel pressure: regulator out of calibration	Replace the pump assembly Op. 1040A70
			Low fuel pressure: defective pump	Replace the pump assembly Op. 1040A70
8	CHECK THE VARIABLE VALVE TIMING SOLENOID	All OK	Problems met	Operation
1.6 TS 120 CV	Carry out active diagnosis of variable valve timing	Continue to Step 10	Solenoid not working	Continue to Step 9
2.0 TS	Carry out active diagnosis of variable valve timing	Continue to Step 10	Solenoid not working	Continue to Step 9
9	CHECK VARIABLE VALVE TIMING ELECTRICAL CIRCUIT	All OK	Problems met	Operation
1.6 TS 120 CV	Check power and earth of variable valve timing system solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 10	Variable valve timing faulty	Replace the phase transformer Op. 1036C40
1.6 TS 120 CV		Continue to Step 10	Connections not correct	Restore the connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
2.0 TS	Check power and earth of variable valve timing system solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 10	Variable valve timing faulty	Replace the phase transformer Op. 1036C40
2.0 TS		Continue to Step 10	Connections not correct	Restore the connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
10	TIMING VARIATOR CHECK	All OK	Problems met	Operation
1.6 TS 120 CV	Check the operation of the variable valve timing system by powering the solenoid of the variator directly. There must be a significant variation in engine speed (surging or very irregular idling)	Continue to Step 11	No speed changes: variable valve timing stuck	Replace the phase transformer Op. 1036C40
2.0 TS	Check the operation of the variable valve timing system by powering the solenoid of the variator directly. There must be a significant variation in engine speed (surging or very irregular idling)	Continue to Step 11	No speed changes: variable valve timing stuck	Replace the phase transformer Op. 1036C40
11	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 12	Timing not correct	Restore the correct timing Op. 1032B10
12	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists: control unit defective	Replace control unit Op. 1056B82

1.9 JTD 8V

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check: the condition of the air intake circuit condition and correct operation of the air filter	Continue to Step 1	Fault in air intake circuit	Repair the air intake circuit
		Continue to Step 1	Air filter blocked	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 Check: that there are no errors in the control unit plausibility of all the parameters carry out active diagnosis of E.G.R. solenoid	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
			Unreliable 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
			Solenoid not working	Check the continuity of the wiring See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENTand if necessary replace the solenoid
2	CHECK ON FUEL FILTER	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	VALVE CLEARANCE CHECK	All OK	Problems met	Operation
	Check that the valve tappet clearance is correct.	Continue to Step 4	Valve clearance not correct	Adjust the tappets Op. 1036H10
4	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test	Continue to Step 6	Cylinder compression insufficient	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	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. 1060G80

1.9 JTD 16V

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check: the condition of the air intake circuit condition and correct operation of the air filter	Continue to Step 1	Fault in air intake circuit	Repair the air intake circuit
		Continue to Step 1	Air filter blocked	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 Check: that there are no errors in the control unit plausibility of all the parameters carry out active diagnosis of E.G.R. solenoid	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
			Unreliable 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
			Solenoid not working	Check the continuity of the wiring See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENTand if necessary replace the solenoid Op. 1080C74
2	CHECK ON FUEL FILTER	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	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test	Continue to Step 5	Cylinder compression insufficient	Continue to Step 4
4	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 5	Insufficient valve seal	Overhaul the cylinder head Op. 1016E10
5	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. 1060G80

All versions

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 the condition of the spark plugs	Continue to Step 1	Fault in air intake circuit	Restore the correct operation of the intake circuit
		Continue to Step 1	Spark plugs worn, fouled or 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; the plausibiilty of the parameters, in particular: accelerator pedal position throttle self-learning target and actual idle speeds rail pressure - rail pressure setting	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 2	Inconsistent parameter	Anaylze the factors that have caused this inconsistency
2	PETROL VAPOUR RECOVERY SYSTEM CHECK	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 seepage	Restore the correct seal
		Continue to Step 3	Pipe between solenoid valve and manifold damaged	Replace the pipe
3	PETROL VAPOUR RECOVERY SYSTEM CHECK	All OK	Problems met	Operation
	Carry out active diagnosis of solenoid; check that the air port opens and closes mechanically.	Continue to Step 4	Solenoid not working	Check supply and earth of petrol vapour recovery solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 4	Mechanical failure: solenoid valve remains open	Replace the solenoid valve
4	BRAKE SERVO AND PIPE CHECK	All OK	Problems met	Operation
	Check the condition of the brake servo vacuum pipes; See Test 3330DA Check operation of brake servoCheck the operation of the single-active valve and the brake servo	Continue to Step 5	Brake servo pipe defective	Replace the pipe
		Continue to Step 5	Brake servo defective	Replace the brake servo/pump assembly
5	CHECK THE VARIABLE VALVE TIMING SOLENOID	All OK	Problems met	Operation
	Carry out active diagnosis of variable valve timing	Continue to Step 8	Solenoid not working	Continue to Step 6
6	CHECK VARIABLE VALVE TIMING ELECTRICAL CIRCUIT	All OK	Problems met	Operation
	Check power and earth of variable valve timing system solenoid See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT	Continue to Step 7	Connections not correct	Restore the connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
7	TIMING VARIATOR CHECK	All OK	Problems met	Operation
	Check the operation of the variable valve timing system by powering the solenoid of the variator directly. There should be a considerable variation in the engine speed (very irregular idling or surging).	Continue to Step 8	No speed changes: variable valve timing stuck	Replace the phase transformer Op. 1036C40
8	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 9	Timing not correct	Restore the correct timing
9	CHECK ON INJECTORS	All OK	Problems met	Operation
	Check the condition of the injectors, in particular make sure that there is no reduced fluxing	Continue to Step 10	Injector faulty	Replace injector
10	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 12	Cylinder compression insufficient	Continue to Step 11
11	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	All OK	Problems met	Operation
	Carry out R/R on head to check the valve seal Check the condition of the cylinders/piston rings	Continue to Step 12	Insufficient valve seal	Overhaul the cylinder head
		Continue to Step 12	Cylinders/piston rings worn	Repair the leak
12	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 control unit Op. 1056B82

3.2 V6

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the condition of the air filter the condition of the air intake circuit	Continue to Step 1	Air filter blocked	Replace the filter element Op. 1048A14
		Continue to Step 1	Fault in air intake circuit	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 as instructed in the Table 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	PETROL VAPOUR RECOVERY SYSTEM CHECK	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 seepage	Restore the correct seal
		Continue to Step 3	Pipe between solenoid valve and manifold damaged	Replace the pipe
3	PETROL VAPOUR RECOVERY SOLENOID VALVE CHECK	All OK	Problems met	Operation
	Carry out active diagnosis of solenoid	Continue to Step 5	Solenoid not working	Continue to Step 4
4	SOLENOID VALVE ELECTRICAL CIRCUIT CHECK	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	Connections not correct	Restore the connections See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
5	BRAKE SERVO AND PIPE CHECK	All OK	Problems met	Operation
	Check the condition of the brake servo vacuum pipes; 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 defective	Replace the pipe
		Continue to Step 6	Brake servo defective	Replace the brake servo/pump assembly
6	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 7	Insufficient fuel pressure: pipe obstructed	Eliminate the blockage; if necessary replace the pipe
	Check the fuel supply pressure Op. 0510C10	Continue to Step 7	Low fuel pressure: defective pump	Replace the pump assembly Op. 1040A70
7	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 8	Timing not correct	Restore the correct timing
8	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 control unit Op. 1056B82

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