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 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	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 vacuum circuit and vacuum unit	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