23 · Diagnostics

Engine idling too low

Make: Alfa Romeo
Model: 159 Factory Service Manual
Year: 2005–2011
Section: Engine › Engine idling too low

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Fault diagnosisEngine idling too low

ENGINE IDLING TOO LOW

1.9 JTD 8V, 1.9 JTD 16V, 2.4 JTD 20V

The customer complains of: Engine idle speed too low

1	AMBIENT PARAMETERS CHECK	All OK	Problems encountered	Operation
		Results of the tests
	Select the following control unit at the diagnostic equipment: EDC16C39 Diesel electronic injection control unit. Check the value of the following parameters: . Battery voltage See Test 5530BB BATTERY VOLTAGE CHECK . Accelerator pedal . Accelerator position 1 AD/C . Accelerator position 2 AD/C See Test 1068AC ACCELERATOR PEDAL CHECKS . Engine rpm See Test 1060GI ENGINE SPEED CHECK . Objective Diesel pressure . Measured Diesel pressure See Test 1060GH DIESEL FUEL PRESSURE CHECK	Move on to Step 2
2	CONFIGURATION TESTS	All OK	Problems encountered	Operation
	Select the following control unit at the diagnostic equipment: EDC16C39 Diesel electronic injection control unit. Check in the Configurations section whether the replacement of any of the following components was not followed by the subsequent configuration: . Flow meter . Fuel pressure sensor . Injector . Differential pressure sensor on the catalytic converter . Lambda sensor . Main catalytic converter with filter . Pre-catalyzer In this case, carry out the configuration checking that the outcome is positive	Move on to Step 4	The outcome of the configuration is not positive	Move on to Step 3
3	CONFIGURATION REPETITION	All OK	Problems encountered	Operation
	Repeat the configuration, check that the outcome is positive this time	Move on to Step 4	The outcome of the configuration is not positive	Replace the engine management control unit Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R
4	ELECTRICAL EQUIPMENT CHECK	All OK	Problems encountered	Operation
	Check that fuse F1 has not blown (it is the last one at the bottom of the vertical row). The check on the following system is only necessary if the outside temperature is below 0 °C.	Move on to Step 5	Fuse F1 has blown	Restore the connections or, if necessary, replace the junction unit in the engine compartment Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.
		Move on to Step 5	Fuse F1 has blown		5	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
	Carry out the active diagnosis for the E.G.R. solenoid valve	Move on to Step 6	Solenoid valve not working	Restore the wiring continuity See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the solenoid valve if necessary Op. 1080C24 E.G.R. SYSTEM SOLENOID - R + R
6	FUEL FILTER CHECK	All OK	Problems encountered	Operation
	Check fuel filter operation	Move on to Step 7	Water, petrol, paraffin or dirt found to be present	Clean the tank and pipes and replace the diesel filter cartridge Op. 1044B20
7	VALVE CLEARANCE CHECK	All OK	Problems encountered	Operation
	Check that the tappet clearance is correct Op. 1036H10 VALVE TAPPETS - CHECK AND ADJUST CLEARANCE, IF NECESSARY	Move on to Step 8	Valve clearance not correct	Adjust the tappets
8	CYLINDER COMPRESSION CHECK	All OK	Problems encountered	Operation
	Carry out the cylinder compression check Op. 0520G15 COMPRESSION TEST - CHECK WITH EXAMINER WITH SPARK PLUGS/INJECTORS REMOVED	Move on to Step 10	Cylinder compression insufficient	Move on to Step 9
9	CHECK THE CAUSE OF THE INSUFFICIENT COMPRESSION	All OK	Problems encountered	Operation
	Carry out Op. 1016C10 SINGLE CYLINDER HEAD - R.R. AND REPLACE GASKET to check the valve seal and check the condition of the cylinders/piston rings	Move on to Step 10	Valve seal insufficient	Overhaul the cylinder head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
10	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Replace the engine management control unit Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - .R

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