23 · Diagnostics

Engine idle irregular

Make: Fiat
Model: Ducato Factory Service Manual
Year: 2002–2006
Section: Engine › Engine idle irregular

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Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

Engine idles unevenly. In particular, level is not consistent and regular when load is altered (e.g. activation of appliances etc.)

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the air intake circuit Check condition of the air filter and ensure it is working properly	Move on to Step 1	Fault in the air intake circuit	Renew the air intake circuit
		Move on to Step 1	Filter blocked	Replace the filter element Op. 1048A14 AIR CLEANER FILTERING ELEMENT - REPLACE.
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the diagnostic equipment to the diagnostic socket. Check: that there are no errors in the control unit; parameter plausibility	Move on to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameters not plausible	Continue following the instructions for the diagnostic equipment
			No communication with the control unit	Restore the connection between the engine management control unit and the diagnostic connector See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
2	FUEL FILTER CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check fuel filter operation	Move on to Step 3	Water, petrol, paraffin or dirt found to be present	Clean the tank and pipes and replace the filter element Op. 1044B20 FUEL FILTER FILTERING ELEMENT - REPLACE
3	INJECTOR CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check for diesel leaks from the injectors See Test 1060O DIESEL FUEL INJECTION SUPPLY TESTS	Move on to Step 4	One or more injectors found to be leaking	Change the injectors Op. 1060F10 FUEL INJECTORS
4	EGR VALVE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check EGR valve operation following removal	Move on to Step 5	EGR valve blocked open	Replace the EGR valve Op. 1080C10 E.G.R. VALVE - R + R
5	VALVE CLEARANCE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the tappet clearance is correct Op. 1036H14 VALVE TAPPETS - CHECK CLEARANCE	Move on to Step 6	Valve clearance not correct	Replace tappets Op. 1036H10 VALVE TAPPETS - CHECK AND ADJUST CLEARANCE
6	CYLINDER COMPRESSION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Carry out the cylinder compression check	Move on to Step 8	Cylinder compression insufficient	Move on to Step 7
7	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	R/R head for valve leakage test. Op. 1016C10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL Check condition of cylinders/piston rings	Move on to Step 8	Valve seal insufficient	Overhaul the head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
8	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the fault is no longer present	End of diagnosis	Fault persists: control unit defective	Replace the engine management control unit Op. 1060G80 DS ELECTRIC INJECTION CONTROL UNIT - R R

BIPOWER

Engine idles unevenly. In particular, level is not consistent and regular when load is altered (e.g. activation of appliances etc.)

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	First, check: the condition of the air intake circuit; condition of the air filter; status of spark plugs and leads; correct valve tappet clearance	Move on to Step 1	Air intake circuit component damaged	Replace damaged component
			Filter element dirty or damaged	Replace the filter element Op. 1048A14 AIR CLEANER FILTERING ELEMENT - REPLACE.
			Spark plugs dirty or damaged	Clean or replace the spark plugs
			Spark plug leads damaged	Replace spark plug leads
			Valve clearance not correct	Restore correct valve clearance
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the diagnostic equipment to the diagnostic connector and check the following at the engine management control unit: in error mode: no faults in the petrol engine management control unit; no faults in the methane engine management control unit; in parameters ambient: the plausibility of all the parameters; methane injector diagnosis	Move on to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameters not plausible	Continue following the instructions for the diagnostic equipment
			Injector defective	Replace the injector Op. 1058A70 INJECTOR(1) OF CNG INJECTION SYSTEM - R RWITH CNG MANIFOLD PIPE REMOVED INCLUDES GASKET REPLACEMENT
2	CHECK PRESSURE CIRCUIT SEAL	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check seal of high and low pressure system by carrying out Test 1058C See Test 1058O CNG SUPPLY TESTS	Move on to Step 3	System not sealed	Restore seal
3	CHECK IDLE ACTUATOR USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the petrol engine control unit, in the active diagnosis ambient: correct operation of idle actuator	Move on to Step 4	Idle actuator defective	Replace idle actuator
			Idle actuator rod contact seat dirty	Clean idle actuator rod contact seat
			Actuator connection not correct	Restore correct connection between idle actuator and engine control unit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
4	CHECK METHANE PRESSURE	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the methane engine management control unit, in the parameters ambient: the correct pressure in the methane circuit by carrying out Test 1058OA and Test 1044EB See Test 1058O CNG SUPPLY TESTS See Test 1044E GAS PRESSURE CONTROL DEVICE	Move on to Step 5	Pressure incorrect: methane pressure reduction unit defective	Replace methane pressure reduction unit Op. 1044E10 CNG INJECTION SYSTEM PRESSURE REDUCTION UNIT - R R
			Pressure not correct: methane pressure sensor blocked	Replace methane pressure reduction unit Op. 1044E10 CNG INJECTION SYSTEM PRESSURE REDUCTION UNIT - R R
			Pressure not correct: methane leaks from system	Eliminate leaks from methane system
5	CHECK METHANE INJECTORS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the methane engine management control unit, in the active diagnosis ambient: correct operation of methane injectors. Check correct injector seal by carrying out Test 1058OB See Test 1058O CNG SUPPLY TESTS	Move on to Step 6	Methane injector defective	Replace the injector Op. 1058A70 INJECTOR(1) OF CNG INJECTION SYSTEM - R RWITH CNG MANIFOLD PIPE REMOVED INCLUDES GASKET REPLACEMENT
		Move on to Step 6	Petrol injectors permanently open	Replace the injectors
6	TIMING CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the valve gear timing is correct	End of diagnosis	Valve gear timing not correct	Restore the correct valve gear timing

GPL

Engine idles unevenly. In particular, level is not consistent and regular when load is altered (e.g. activation of appliances etc.)

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	First, check: the condition of the air intake circuit; condition and cleanliness of air filter; correct status of spark plugs and leads; correct valve tappet clearance. If repairs are carried out to the flywheel or the rpm sensor or after the petrol engine management control unit has been replaced, check that: the diagnostic equipment has been used to zero the self-adjustment parameters for restoring the control unit maps	Move on to Step 1	Air intake circuit component damaged	Replace damaged component
			Filter element dirty or damaged	Replace the filter element Op. 1048A14 AIR CLEANER FILTERING ELEMENT - REPLACE.
			Spark plugs dirty or damaged	Clean or replace the spark plugs
			Spark plug leads damaged	Replace spark plug leads
			Valve clearance not correct	Restore correct valve clearance Op. 1036H10 VALVE TAPPETS - CHECK AND ADJUST CLEARANCE
			Self-adjustment parameters not zeroed	Carry out zeroing
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the diagnostic equipment to the diagnostic connector and check the following at the engine management control unit: in the errors ambient: no faults in the petrol engine management control unit; no faults in the LPG engine management control unit; in parameters ambient: the plausibility of all the parameters	Move on to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameters not plausible	Continue following the instructions for the diagnostic equipment
			No dialogue with the petrol control unit	Restore the connection between the engine management control unit and the diagnostic connector See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
			No dialogue with the LPG control unit	Restore the connection between the engine management control unit and the diagnostic connector See E5031 LPG FUEL SYSTEM ELECTRONIC MANAGEMENT
2	CHECK IDLE ACTUATOR USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the petrol engine control unit, in the active diagnosis ambient: correct operation of idle actuator	Move on to Step 3	Idle actuator defective	Replace idle actuator
			Idle actuator rod contact seat dirty	Clean idle actuator rod contact seat
			Actuator connection not correct	Restore correct connection between idle actuator and engine control unit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
3	LPG INJECTOR CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the LPG engine management control unit, in the active diagnosis ambient: the correct operation of the LPG injectors. Check that the injectors are not leaking See Test 1057B GPL MULTIPOINT INJECTION FUEL SYSTEM	Move on to Step 4	LPG injector defective	Replace the injector
4	RETURN SOLENOID VALVE EFFICIENCY CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the LPG engine management control unit, in the active diagnosis ambient: the correct operation of the return solenoid valve. Check the electrical operation of LPG return solenoid valve See Test 1043B GPL FUEL CIRCUIT PIPES	Move on to Step 5	Solenoid defective	Replace the solenoid valve
5	CHECK LPG PRESSURE	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the LPG engine management control unit, in the parameters ambient and with the engine running: the correct LPG pressure	Move on to Step 6	Pressure not correct: multivalve calibrated port defective	Replace multivalve
			Pressure not correct: LPG pressure sensor blocked	Replace LPG pressure sensor
			Pressure not correct: LPG leaks from system	Eliminate leaks from the LPG system
6	CHECK LPG PUMP EFFICIENCY	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Keeping the diagnostic equipment connected to the diagnostic connector check the following at the LPG engine management control unit, in the active diagnosis ambient: correct operation of the LPG pump Check the operation of the LPG warning light See Test 1043A GPL TANK	Move on to Step 7	Irregular absorption by the LPG pump	Replace the LPG pump
		Move on to Step 7	Wiring defective	Restore wiring See E5031 LPG FUEL SYSTEM ELECTRONIC MANAGEMENT
7	TIMING CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the valve gear timing is correct	End of diagnosis	Valve gear timing not correct	Restore the correct valve gear timing Op. 1032B14 TOOTHED TIMING BELT - R + R FOR TIMING ADJUSTMENT OR REPLACEMENT VERSIONS WITH AIR CONDITIONER

All versions

Engine idles unevenly. In particular, level is not consistent and regular when load is altered (e.g. activation of appliances etc.)

STEP	OPERATIONS TO BE CARRIED OUT	TEST RESULTS
0	PRELIMINARY CHECKS	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check the condition of the air intake circuit. Check condition of the air filter and ensure it is working properly	Move on to Step 1	Air intake circuit faulty	Renew the air intake circuit
		Move on to Step 1	Filter blocked	Replace the filter element Op. 1048A14 AIR CLEANER FILTERING ELEMENT - REPLACE.
1	CHECK USING DIAGNOSTIC EQUIPMENT	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Connect the diagnostic equipment to the diagnostic socket. Check: that there are no errors in the control unit; parameter plausibility	Move on to Step 2	Error detected in the control unit	Continue following the instructions for the diagnostic equipment
			Parameters not plausible	Continue following the instructions for the diagnostic equipment
			No communication with the control unit	Restore the connection between the engine management control unit and the diagnostic connector See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
2	FUEL FILTER CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check fuel filter operation	Move on to Step 3	Water, petrol, paraffin or dirt found to be present	Clean the tank and pipes and replace the filter element Op. 1044B20 FUEL FILTER FILTERING ELEMENT - REPLACE
3	INJECTOR CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check for diesel leaks from the injectors See Test 1060O DIESEL FUEL INJECTION SUPPLY TESTS	Move on to Step 4	One or more injectors found to be leaking	Change the injectors Op. 1060F10 FUEL INJECTORS
4	EGR VALVE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check EGR valve operation following removal	Move on to Step 5	EGR valve blocked open	Replace the EGR valve Op. 1080C10 E.G.R. VALVE - R + R
5	VALVE CLEARANCE CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the tappet clearance is correct Op. 1036H14 VALVE TAPPETS - CHECK CLEARANCE	Move on to Step 6	Valve clearance not correct	Adjust the tappets Op. 1036H10 VALVE TAPPETS - CHECK AND ADJUST CLEARANCE
6	CYLINDER COMPRESSION CHECK	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Carry out the cylinder compression check	Move on to Step 8	Cylinder compression insufficient	Move on to Step 7
7	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	R/R head for valve leakage test. Op. 1016C10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL Check condition of cylinders/piston rings	Move on to Step 8	Valve seal insufficient	Overhaul the head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
8	CHECK ON CORRECT OPERATION	ALL OK	PROBLEMS ENCOUNTERED	ACTION
	Check that the fault is no longer present	End of diagnosis	Fault persists: control unit defective	Replace the engine management control unit Op. 1060G80 DS ELECTRIC INJECTION CONTROL UNIT - R R

‹ Prev Engine does not produce best performance Next › Engine cuts out whilst driving

Parts & tools for this job For 2002 Fiat Ducato

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