22 · Diagnostics

Engine idle irregular

Make: Fiat
Model: Multipla Factory Service Manual
Year: 1998–2010
Section: Engine › Engine idle irregular

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

Fault diagnosisEngine idle irregular

ENGINE IDLE IRREGULAR

1.6 16v

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.).

1.6 16v · BIPOWER

The engine idles unevenly; in particular, the level is not consistent and regular when the load is altered (e.g. consumers switched on, etc.).

NOTE: After system components have been replaced the self-adjustment parameters must be zeroed in order to restore the values originally set in the factory to the control unit maps

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Results of the tests
1	CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
2	CHECK PRESSURE CIRCUIT SEAL	All OK	Problems encountered	Operation
3	CHECK IDLE ACTUATOR USING DIAGNOSTIC EQUIPMENT	All OK	Problems encountered	Operation
4	CHECK METHANE PRESSURE	All OK	Problems encountered	Operation
5	INTAKE PRESSURE CHECK	All OK	Problems encountered	Operation
6	CHECK METHANE INJECTORS	All OK	Problems encountered	Operation

1.6 16v

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
	Using the diagnostic equipment (Examiner or other iinstruments) carry out active diagnosis on the idle actuator	Continue to Step 3	Idle actuator connection defective	Restore connection between idle actuator and control unit, See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
		Continue to Step 3	Idle actuator defective	Replace the idle actuator Op. 1056B56
3	CHECKING LAMBDA SENSOR	All OK	Problems met	Operation
	Check that the Lambda sensor is working properly	Continue to Step 4	Lambda sensor not working properly	Replace the Lambda sensor Op. 1080B60
4	VAPOUR RECOVERY SYSTEM CHECK	All OK	Problems met	Operation
	Check the condition and the seal of the vapour recovery pipes	Continue to Step 5	Pipes obstructed or have extremely small holes	Restore the vapour recovery pipes and replace if necessary (see Assembly 1080E)
5	CHECK VACUUM PIPE	All OK	Problems met	Operation
	Check condition and fitting of vacuum pipe	Continue to Step 6	Pipe fitted incorrectly or bent	Refit correctly
	Check condition and fitting of vacuum pipe	Continue to Step 6	Pipe damaged	Replace the vacuum pipe Op. 3330D24
6	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 7	Pressure not correct	Replace the fuel pump assembly Op. 1040A70
7	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the engine timing is correct	Continue to Step 8	Timing not correct	Restore the correct engine timing Op. 1032B14
8	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 9	Compression values not correct	Restore the correct cylinder compression, e.g by checking the injector seal Op. 1056B70
9	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists

1.9 JTD 8V

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.).

1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
		Results of the tests
	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 E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
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 filter element Op. 1044B20
3	CHECKING AIR CIRCUIT	All OK	Problems met	Operation
	Check, in order: the condition of the air filter the condition and seal of the air supply circuit	Continue to Step 4	Filter dirty or partially blocked	Replace the air filter Op. 1048A14
		Continue to Step 4	Circuit component damaged	Replace the component (see Assembly 1048A)
4	VALVE CLEARANCE CHECK	All OK	Problems met	Operation
	Check that the valve tappet clearance is correct. Op. 1036H14	Continue to Step 5	Clearance not correct	Restore the correct valve clearance. Op. 1036H18
5	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 6	Compression values not correct	Restore the correct cylinder compression, e.g by checking the injector seal Op. 1060F10
6	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

1.6 16v · GPOWER

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 intake circuit condition of air filter the state of the spark plugs and leads that the valve tappet clearance is correct In the case of operations on the flywheel or the rpm sensor or after replacing the petrol engine management control unit, Check that: The self-adjustment parameters for restoring the maps in the control unit have been zeroed using the Examiner The flywheel zeroing/learning has been carried out	Continue to Step 1	Air intake circuit component damaged	Replace damaged component
			Filter element dirty or damaged	Replace the filter element Op. 1048A14
			Spark plugs dirty or damaged	Clean or replace the spark plugs
			Spark plug leads damaged	Replace the spark plug leads Op. 5510D14
			Valve clearance not correct	Restore the correct valve clearance
			Self-adjustment parameters not zeroed	Carry out zeroing
			No flywheel zeroing/learning	Carry out zeroing
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the Examiner diagnostic equipment to the diagnostic connector and check the following at the engine management control units: in errors ambient that there are no faults in the petrol engine management control unit that there are no faults in the LPG engine management control unit In parameters ambient the plausibility of all the parameters.	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 the engine management control unit and the diagnostic connector
2	IDLE ACTUATOR CHECK USING DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check the following at the petrol engine management control unit: in active diganosis ambient that the idle actuator is working properly	Continue to Step 3	Idle actuator defective	Replace the idle actuator Op. 1056B43
			Idle actuator push rod seat dirty	Clean the idle actuator push rod seat
			Actuator connection not correct	Restore the correct connection between the idle actuator and the engine management control unit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
3	LPG PRESSURE CHECK	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check the following at the petrol engine management control unit: in parameters ambient that the LPG pressure is correct See Test 1057BA LPG pressure check	Continue to Step 4	Pressure not correct: LPG pressure regulator defective	Replace the LPG pressure regulator Op. 1043B42
			Pressure not correct: LPG pressure sensor incorrectly adjusted	Replace the LPG pressure regulator Op. 1043B42
			Pressure not correct: Leaks of LPG from the system	Eliminate the LPG system leaks
4	LPG PUMP EFFICIENCY CHECK	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check the following at the petrol engine management control unit: in active diagnosis ambient that the LPG pump is working properly Check the operation of the LPG pump See Test 1043AA Check operation of LPG pump	Continue to Step 5	LPG pump absorption faulty	Replace the LPG pump Op. 1043A57
		Continue to Step 5	Faulty wiring	Renew the wiring See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
5	LPG INJECTORS CHECK	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check the following at the LPG engine management control unit: in active diagnosis ambient that the LPG injectors are working properly Check that the injectors are not leaking See Test 1043BC LPG injector seal check	Continue to Step 6	LPG injector defective	Replace the injector Op. 1057B66
6	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the timing is correct	Continue to Step 7	Timing not correct	Restore the correct timing
7	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis

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

Parts & tools for this job For 1998 Fiat Multipla

Links open Amazon search results in a new tab. As an Amazon Associate I earn from qualifying purchases.