D10 ENGINE IDLE IRREGULAR - Alfa - 156 - eLearn

3233019 - D10 ENGINE IDLE IRREGULAR

The engine is not running smoothly when idling; in particular, it does not maintain a constant, regular value as the load varies (e.g. when electrical devices are switched on, etc.)

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the state of the spark plugs and leads condition of air filter the condition of the air intake circuit	Continue to Step 1	Spark plugs dirty or damaged	Clean or replace the spark plugs Op. 5510D10
			Spark plug leads damaged	Replace the spark plug leads Op. 5510D14
			Filter element dirty or damaged	Replace the filter element Op. 1048A14
			Air intake circuit component damaged	Replace the component (see Assembly 1048A)
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 plausibility of all the parameters.	Continue to Step 2	An error is detected in the control unit	Continue according to 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	IDLE CHECK WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
1.6 TS	Using the diagnostic equipment (Examiner or other iinstruments) carry out active diagnosis on the idle actuator	Continue to Step 3	Idle actuator connection faulty	Renew the connection between the idle actuator and the control unit, ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT )
1.6 TS		Continue to Step 3	Idle actuator faulty	Replace the idle actuator Op. 1056B43
1.8 TS [d] 2.5 V6	Check that the idle 'learning' by the engine management control unit is correct	Continue to Step 3	Idle 'learning' not correct	Make the control unit carry out the correct idle 'learning'
3	ACTIVE DIAGNOSIS WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the injectors	Continue to Step 4	Injector connections faulty	Restore the connection of the injectors with the control unit, ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT )
		Continue to Step 4	Injectors faulty	Replace the injectors Op. 1056B70
4	COIL CHECK	All OK	Problems met	Operation
2.5 V6	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the injectors	Continue to Step 5	Coils connection faulty	Restore the connection for the coils with the control unit, ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT )
2.5 V6		Continue to Step 5	Ignition coils faulty	Replace the ignition coils Op. 5510C14
1.6 TS 1.8 TS [d]	Check, in order: coil supply connection of the coils with the engine management control unit connection of the spark plugs with the coils the operation of the coils ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT )	Continue to Step 5	Connections not correct	Restore the connections
1.6 TS 1.8 TS [d]		Continue to Step 5	Ignition coils faulty	Replace the ignition coils Op. 5510C14
5	CHECKING LAMBDA SENSOR	All OK	Problems met	Operation
1.6 TS	Check that the Lambda sensor is working properly See Test 1080BA Checking Lambda sensor	Continue to Step 6	Lambda sensor not working properly	Replace the Lambda sensor Op. 1080B60
1.8 TS [d] 2.5 V6	Check that the Lambda sensor is working properly See Test 1080BB Check operation of fuel vapour recovery solenoid valve	Continue to Step 6	Lambda sensor not working properly	Replace the Lambda sensor Op. 1080B60
6	VAPOUR RECOVERY SYSTEM CHECK	All OK	Problems met	Operation
	Check the condition and the seal of the vapour recovery pipes	Continue to Step 7	Pipes obstructed or have extremely small holes	Renew vapour recovery pipes, if necessary, replace them (see Assembly 1080E)
7	BRAKE SERVO VACUUM CHECK	All OK	Problems met	Operation
	Check the condition of the vacuum pipe and connectors and bands	Continue to Step 8	Fixings or components faulty.	Renew the fixings or replace the faulty components
		Continue to Step 8	Pipe damaged	Replace the vacuum pipe
8	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 9	Pressure not correct	Replace the fuel pump assembly Op. 1056B70
9	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 10	Compression values not correct	Restore the correct cylinder compression, for example, checking the seal of the injectors Op. 1056B70 and the cylinders (see OVERHAULING ENGINE, Subassembly 1004)
10	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the engine timing is correct Op. 0510A20	Continue to Step 11	Timing not correct	Restore the correct engine timing Op. 1032B14
11	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'