Engine not running smoothly / (irregular operation)

Make: Fiat
Model: Doblò Factory Service Manual
Year: 2000–2010
Section: Engine › Engine not running smoothly / (irregular operation)

‹ Prev Engine not running smoothly / (losing power)Next › Engine not running smoothly

Fault diagnosisEngine not running smoothly / (irregular operation)

ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

Missing at constant speed or during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the condition of the air filter the state of the spark plugs and leads; battery earth correctly fixed See E1010 SUPPLY	Continue to Step 1	Filter element dirty, damaged or incorrectly fitted	Replace or refit filter element correctly Op. 1048A14
			Spark plugs dirty or damaged	Replace the spark plugs Op. 5510D10
			Spark plug leads damaged	Replace the spark plug leads Op. 5510D14
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
			'Upstream lambda sensor' error detected	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL 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	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Road test the vehicle, reproducing the conditions in which the fault arises, keeping the diagnostic equipment connected. check that there are no faults in the engine management control unit; plausibility of all the parameters	Continue to Step 3	'Supply system' error detected	See table Z50 MIXTURE STRENGTH ERROR
			'Upstream lambda sensor' error detected	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			Sudden occurrence of another error in the control unit detected	Continue following the instructions for the diagnostic equipment
			Inconsistent parameter	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
1.2 8v Climatizzatore	Check, if necessary on the road (to reproduce the conditions in which the fault arises), the fuel supply pressure Op. 0510C10in the conditions in which the fault arises	Continue to Step 4	Pressure not correct: obstructions in fuel delivery pipe	Remove the obstructions in the fuel pipe, and if necessary replace it Op. 1040B34
			Pressure not correct: tank insufficiently ventilated	Restsore the tank ventilation
			Pressure not correct: fuel pump electrical circuit broken	Repair fuel pump electrical circuit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
			Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
	Check, if necessary on the road (to reproduce the conditions in which the fault arises), the fuel supply pressure Op. 0510C10	Continue to Step 5	Pressure not correct: obstructions in fuel delivery pipe	Remove the obstructions in the fuel pipe, and if necessary replace it Op. 1040B34
			Pressure not correct: tank insufficiently ventilated	Restsore the tank ventilation
			Pressure not correct: fuel pump electrical circuit broken	Repair fuel pump electrical circuit See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
			Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
4	CHECK AIR CONDITIONING SYSTEM	All OK	Problems met	Operation
1.2 8v Climatizzatore	Road test the vehicle and check whether the fault is affected by whether or not the air conditioner is switched on	Continue to Step 5	Fault present only with the air conditioner on	See table L10 CLIMATE CONTROL NOT COOLING
5	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

Missing at constant speed or during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the condition of the air filter battery earth correctly fixed See E1010 SUPPLY	Continue to Step 1	Filter element dirty, damaged or incorrectly fitted	Replace or refit filter element correctly Op. 1048A14
		Continue to Step 1	Earth fastening not correct	Renew the wiring
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	Continue according to the instructions for the See table Z50 MIXTURE STRENGTH ERROR
			'Upstream lambda sensor' error detected	Continue according to the instructions for the See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL 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	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Road test the vehicle, reproducing the conditions in which the fault arises, keeping the diagnostic equipment connected. check that there are no faults in the engine management control unit; plausibility of all the parameters	Continue to Step 3	'Supply system' error detected	Continue according to the instructions for the See table Z50 MIXTURE STRENGTH ERROR
			'Upstream lambda sensor' error detected	Continue according to the instructions for the See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR
			Sudden occurrence of another error in the control unit detected	Continue following the instructions for the diagnostic equipment
			Inconsistent parameter	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check, if necessary on the road (to reproduce the conditions in which the fault arises), the fuel supply pressure Op. 0510C10	Continue to Step 4	Pressure not correct: obstructions in fuel delivery pipe	Remove the obstructions in the fuel pipe, and if necessary replace it
		Continue to Step 4	Pressure incorrect: fuel pump damaged	Replace fuel pump assembly Op. 1040A70
4	CHECK AIR CONDITIONING SYSTEM	All OK	Problems met	Operation
	Road test the vehicle and check whether the fault is affected by whether or not the air conditioner is switched on	Continue to Step 5	Fault present only with the air conditioner on	Continue according to the instructions for the See table L10 CLIMATE CONTROL NOT COOLING
5	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

Missing at constant speed or during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check, in order: the condition of the air intake circuit that there are no obstructions in the catalyzer that there is no water in the diesel that there is diesel in the tank, and its quality	Continue to Step 1	Fault in air intake circuit	Repair the air intake circuit
			Obstruction in the catalyzer	Replace the catalyzer Op. 1080B62
			Presence of water or other impurities in the diesel	Eliminate the impurity from the diesel and clean the tank Op. 1040A10
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket check for errors in the control unit 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
		Continue to Step 2	unreliable parameters	Continue following the instructions for the diagnostic equipment
2	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Road test the vehicle keeping the diagnostic instrument connected. Make sure that the conditions in which the problem occurs are reproduced check for errors in the control unit plausibility of all the parameters	Continue to Step 3	Errors suddenly occur in the control unit	Continue following the instructions for the diagnostic equipment
		Continue to Step 3	Parameters off scale	Continue following the instructions for the diagnostic equipment
3	CHECK ON FUEL INJECTION PUMP TIMING	All OK	Problems met	Operation
1.9 DIESEL Climatizzatore	Check the timing of the fuel injection pump Op. 1060A20	Continue to Step 4	Fuel injection pump timing set incorrectly	Restore the correct timing Op. 1060A20
	Check the timing of the fuel injection pump Op. 1060A20	Continue to Step 5	Fuel injection pump timing set incorrectly	Restore the correct timing Op. 1060A20
4	CHECK AIR CONDITIONING SYSTEM	All OK	Problems met	Operation
1.9 DIESEL Climatizzatore	Road test the car to see if the defective behaviour is affected by air conditioner activation	Continue to Step 5	Fault present only with the air conditioner on	See table L10 CLIMATE CONTROL NOT COOLING
5	CHECK ON BRAKE PEDAL SWITCH	All OK	Problems met	Operation
	Check that the brake pedal switch is working properly See E2021 BRAKE LIGHTS	Continue to Step 6	Brake pedal does not return	Eliminate the cause of the sticking
			Switch stuck in closed position	Replace the switch Op. 5550D10
			Wiring short circuited	Eliminate the cause of the problem See E2021 BRAKE LIGHTS
6	CHECK ON FUEL INJECTION PUMP	All OK	Problems met	Operation
	Check that the fuel injection pump is working correctly	Continue to Step 7	Pump faulty	Replace the pump Op. 1060A10
7	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. 1060D80

Missing at constant speed or during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Check, in order: the condition of the air intake circuit that there are no faults in the air filter whether the diesel pipes are leaking that there is no water, petrol, paraffin or dirt in the fuel tank and filter that the battery earth is correctly fixed	Continue to Step 1	Fault in air intake circuit	Repair the air intake circuit
			Air filter blocked	Replace the filter element
			Leak from diesel pipes	stop the leak
			Presence of water, petrol, parffin or dirt detected.	Clean the tank and pipes and replace the filter element
			Loose battery earth terminal Renew the air intake circuit	Restore the correct fixing of the earth cable
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket check for errors in the control unit 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
		Continue to Step 2	unreliable parameters	Continue following the instructions for the diagnostic equipment
2	ROAD TEST WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Road test the vehicle, reproducing the conditions in which the fault arises, keeping the diagnostic equipment connected. check for errors in the control unit plausibility of all the parameters	Continue to Step 3	Error detected in control units	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.
3	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 the engine management control unit Op. 1060G80

BIPOWER

Missing at constant speed or during acceleration

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	check Leads correctly fastened to the battery The engine wiring is correctly fastened to earth Condition of methane filter	Continue to Step 1	Battery leads not correctly fastened	Fasten the leads correctly
			Fastening of cables to engine incorrect	Restore the correct connection
			Filter blocked	Replace the filter
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 methane engine management control unit: in errors ambient: That there are no faults in the methane control unit	Continue to Step 2	An error is detected in the control unit	Continue following the instructions for the diagnostic equipment
2	METHANE PRESSURE CHECK	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check at the engine management control unit that the methane pressure parameter is correct See Test 1044EB Check on methane low pressure circuit See Test 1058AA Check on operation of Methane pressure sensor	Continue to Step 3	Pressure regulator defective	Replace the pressure regulator Op. 1044E16
		Continue to Step 3	Methane pressure sensor defective	Replace the pressure sensor Op. 1058A44
3	METHANE INJECTOR LEAKAGE TEST	All OK	Problems met	Operation
	Check that the methane injectors are not leaking See Test 1058B Methane injector leakage test	Continue to Step 4	Persistent leak from one methane injector	Replace the injector Op. 1058A70
		Continue to Step 4	High and low pressure connector seal poor	Renew the connector seal
4	METHANE INJECTOR CHECK	All OK	Problems met	Operation
	Using the Examiner diagnostic equipment connected to the diagnostic connector, check the following at the methane engine management control unit: in active diagnosis mode: that the injectors are working properly Check the operation of the injectors by carrying out the Test See Test 1058AB Check on Methane injector coil	Continue to Step 5	Methane injectors faulty	Replace the injectors Op. 1058A70
5	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Replace the LPG engine management control unit Op. 1057B80

‹ Prev Engine not running smoothly / (losing power)Next › Engine not running smoothly

Parts & tools for this job For 2000 Fiat Doblò

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