Engine does not produce best performance

Make: Alfa Romeo
Model: 159 Factory Service Manual
Year: 2005–2011
Section: Engine › Engine does not produce best performance

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Fault diagnosisEngine does not produce best performance

ENGINE DOES NOT PRODUCE BEST PERFORMANCE

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

The customer complains of: Reduced engine performance in all operating conditions

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Results of the tests
	Check that the engine oil level is correct Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY Check that the air intake/vacuum circuit is working properly See Test 1048OA AIR INTAKE/VACUUM CIRCUIT CHECK Check the condition of the fuel supply circuit and make sure that it is working properly See Test 1040OA FUEL SUPPLY CIRCUIT CHECK Check the operation of the low pressure supply circuit See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT	Move on to Step 1	Oil level incorrect	Restore the correct engine oil level Op. 0010T11 ENGINE OIL - CHECK LEVEL AND TOP UP, IF NECESSARY
1	AMBIENT PARAMETERS CHECK	All OK	Problems encountered	Operation
	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 . Atmospheric pressure See Test 1060GD ATMOSPHERIC PRESSURE CHECK . Supercharging pressure Objective . Supercharging pressure Measured See Test 1060GF SUPERCHARGING PRESSURE CHECK . Measured air mass See Test 1060GG MEASURED AIR MASS CHECK . Air temperature in the intake manifold See Test 1064BD SUPERCHARGING TEMPERATURE CHECK . Engine coolant temperature See Test 1060OE CHECK ON OPERATION OF COOLANT TEMPERATURE SENSOR . Diesel temperature See Test 1060EA DIESEL FUEL TEMPERATURE CHECK . Objective Diesel pressure . Measured Diesel pressure See Test 1060GH DIESEL FUEL PRESSURE CHECK . Engine rpm See Test 1060GI ENGINE SPEED CHECK	Move on to Step 2
2	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 3	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 3	Fuse F1 has blown		3	TURBOCHARGER ADJUSTMENT CHECK	All OK	Problems encountered	Operation
	Using the diagnostic equipment carry out the active diagnosis for the turbocharger regulating solenoid valve. Check the operation of the variable geometry control actuator See Test 1064BC VARIABLE GEOMETRY TURBOCHARGER ACTUATOR SEAL TEST	Move on to Step 4	Solenoid valve not working	Restore the wiring continuity See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT Replace the solenoid valve if necessary Op. 1064B42 SOLENOID CONTROLLING TURBOCHARGER VANE POSITION ACTUATOR - R.R
		Move on to Step 4	Actuator not working properly	Check the condition of the vacuum circuit, if necessary, replace the damaged components
4	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 5	E.G.R. 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
5	BRAKE PEDAL SWITCH CHECK	All OK	Problems encountered	Operation
	Check that the brake pedal switch is working properly	Move on to Step 6	Brake pedal does not return	Eliminate the cause of the sticking
			Switch stuck closed	Replace the switch Op. 1060G38 BRAKE PEDAL SWITCH - R.R
			Wiring short circuited	Restore the correct connection See E2021 BRAKE LIGHTS - DESCRIPTION
6	TURBOCHARGER CHECK	All OK	Problems encountered	Operation
	Check See Test 1064BA SUPRECHARGING PRESSURE CHECK the operation of the turbocharger	Move on to Step 7	Turbocharger faulty	Replace the turbocharger See Test 1064A10 TURBO CHARGER - R + R
7	HIGH PRESSURE CHECK	All OK	Problems encountered	Operation
	Connect the diagnotsic equipment to the diagnostic socket. Check See Test 1060OD INSPECTION OF THE HIGH PRESSURE FUEL CIRCUIT that the diesel pressure parameter is correct	Move on to Step 15	Pressure not correct	Move on to Step 8
8	LOW RETURN PRESSURE CHECK	All OK	Problems encountered	Operation
	Check See Test 1060OA CHECK ON RETURN LOW PRESSURE FUEL CIRCUIT that the pressure in the return pipe to the tank is less than 1 bar	Move on to Step 9	Pressure above the maximum limit: return pipe to the tank obstructed	Repair the pipe and replace if necessary.
9	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Check See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT that the diesel pressure between the filter and the pressure pump is between 2 and 3 bar	Move on to Step 15	Pressure below the minimum limit or above the maximum value	Move on to Step 10
10	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Constrict the return pipe from the pressure relief valve and carry out the test again See Test 1060OB CHECK ON SUPPLY LOW PRESSURE FUEL CIRCUIT with the pipe constricted, checking that the filter outlet pressure remains below 2 bar	Move on to Step 11	Pressure rises to 5 bar: pressure regulator valve on filter mounting incorrectly adjusted	Replace the valve See Test 1044B16
11	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Check that the difference in pressure upstream and downstream of the filter is less than 1 bar	Move on to Step 12	Difference in pressure more than 1 bar	Replace the fuel filter cartridge Op. 1044B20 FUEL FILTER FILTERING ELEMENT - REPLACE
12	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Check that the supply pump pressure at the filter inlet is more than 2.2 bar	Move on to Step 15	Pressure below 2 bar	Move on to Step 13
13	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Measure the difference in pressure between the electrical pump outlet and the filter inlet checking that it is less than 0.3 bar	Move on to Step 14	Difference in pressure more than 0.3 bar	Replace the pipe
14	LOW SUPPLY PRESSURE CHECK	All OK	Problems encountered	Operation
	Check See Test 1040AA SUPPLY VOLTAGE AND ABSORPTION CURRENT CHECKS that the pump supply voltage is equal to 12V and that the current uptake is between 2 and 10 A	Move on to Step 15	Voltage lower than 12 V	Check electrical wiring See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT
			Current greater than 10 A: pump defective	Replace the fuel pump Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R
			Current less than 2 A: pump obstructed	Replace the fuel pump Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R and clean the fuel tank
15	CHECK CORRECT OPERATION	All OK	Problems encountered	Operation
	Replace the high pressure DRV valve Op. 1060E50 PRESSURE REGULATOR ON PRESSURE PUMP - R.R. and check that the fault is no longer present	End of diagnosis	Fault persists	Move on to Step 16
16	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Replace the high pressure pump Op. 1060E10 DIESEL INJECTION PRESSURE PUMP - R.R. and check that the fault is no longer present	End of diagnosis	Fault persists	Move on to Step 17
17	TIMING CHECK	All OK	Problems encountered	Operation
	Check that the valve gear timing is correct	Move on to Step 18	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
18	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 19	Valve clearance not correct	Adjust the tappets
19	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 21	Cylinder compression insufficient	Move on to Step 20
20	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	All OK	Problems encountered	Operation
	Carry out Op. 1016C10 SINGLE CYLINDER HEAD - R.R. AND REPLACE GASKET to check the valve seal. Check condition of cylinders/piston rings	Move on to Step 21	Valve seal insufficient	Overhaul the head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
		Move on to Step 21	Cylinders/piston rings worn	Restore the seal
21	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

1.9 JTS, 2.2 JTS, 3.2 JTS

The engine power supplied is less than expected. When the accelerator pedal is pressed there is a slight increase in speed or a total lack of acceleration.

0	PRELIMINARY CHECKS	All OK	Problems encountered	Operation
		Test results
	Before starting, check that the MIL warning light is on and that it goes off once the engine has been started. Also check that no accessories have been fitted in the after-market	Move on to Step 1	The MIL warning lights does not come on when the key is inserted	Continue as instructed in the See table K100 MIL WARNING LIGHT NOT WORKING (REMAINS OFF BEFORE STARTING)
			The MIL warning light remains on with the engine started	Continue as instructed in the See table K101 MIL WARNING LIGHT STAYS ON (ENGINE STARTS)
			There are accessories that have been fitted in the after-market	Check that these accessories have been fitted correctly
1	CONTROL UNIT ELECTRICAL CONNECTIONS CHECK	All OK	Problems encountered	Operation
	Check that the electrical connections for the engine management control unit are correct See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT In particular, check that: - the earth is correctly connected - the resistance between the control unit See M010 ENGINE MANAGEMENT ECU and the battery negative See A001 BATTERY is less than 0.5 Ohm	Move on to Step 2	Connection to earth incorrect	Restore the correct connections
		Move on to Step 2	Resistance to battery negative more than 0.5 Ohm	Restore the correct connections
2	CONTROL UNIT FASTENING CHECK	All OK	Problems encountered	Operation
	Check that the control unit is correctly fastened in its housing Op. 1056F82 CONTROL UNIT SINGLE OF INJECTION IGNITION SYSTEM R R	Move on to Step 3	Control unit fastening incorrect	Renew the correct fastening of the control unit Op. 1056F82 CONTROL UNIT SINGLE OF INJECTION IGNITION SYSTEM R R
3	AIR INTAKE CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check there are no faults in the air intake circuit. In particulr, check: - that the air filter is not blocked or fitted incorrectly - that the air intake circuit does not have any irregular constrictions, leaks or is fitted incorrectly	Move on to Step 4	Air filter blocked	Replace the filter element Op. 1048A14 AIR CLEANER FILTER ELEMENT - REPLACE.
			Irregular component	Replace the faulty component Op. 1048 ENGINE AIR SUPPLY CIRCUIT
			Component incorrectly positioned	Refit the component correctly Op. 1048 ENGINE AIR SUPPLY CIRCUIT
4	FUEL FEED CIRCUIT CHECK	All OK	Problems encountered	Operation
	Check there are no faults in the fuel supply circuit by performing the See Test 1040OA FUEL SUPPLY CIRCUIT CHECK	Move on to Step 5	Faults present	The operation to solve the problem is described in the actual test
5	CHECK FOR THE PRESENCE OF IMPURITIES IN THE FUEL	All OK	Problems encountered	Operation
	Check that there are no impurities such as water, alcohol or particles in suspension in the fuel by carrying out the See T FUEL QUALITY CHECK	Move on to Step 6	Faults present	The operation to solve the problem is described in the actual test
6	INJECTOR CHECK	All OK	Problems encountered	Operation
	Check that the injectors are not stuck shut or not perfectly closed by carrying out the See Test 1056BA INJECTOR OPERATION CHECK	Move on to Step 7	Faults present	The operation to solve the problem is described in the actual test
7	DETNATION SENSOR ERRORS CHECK	All OK	Problems encountered	Operation
	Connect the diagnostic equipment and check that none of the following errors is present: P0325, P0330	Move on to Step 8	One or more of the errors indicated is present	Continue as described by the diagnostic equipment
8	IGNITION COIL CHECK	All OK	Problems encountered	Operation
	Check that the ignition coils are correctly fitted in their seats. Also check that they do not show any signs of corrosion or dampness. Lastly, check that the ignition coils are working properly, by carrying out the See Test 5510CC IGNITION COIL CHECK	Move on to Step 9	One of the coils is not fitted correctly	Refit the coil correctly Op. 5510C14 IGNITION COIL/S - R.R.
			One of the coils shows signs of corrosion/dampness	Replace the coil Op. 5510C14 IGNITION COIL/S - R.R.
			One of the coils is not working properly
9	SPARK PLUGS CHECK	All OK	Problems encountered	Operation
	Remove the spark plugs Op. 5510D10 SPARK PLUGS - R+R and check that they are no signs of faults, following the instructions in the See T SPARK PLUG STATE CHECK	Move on to Step 10	Faults present	The operation to solve the problem is described in the actual test
10	RPM SENSOR CHECK	All OK	Problems encountered	Operation
	Check that the resistance value of the rpm sensor in all temperature ranges is between 700 and 1200 Ohm	Move on to Step 11	Resistance values outside of the range	Change the rpm sensor Op. 5510C26 ENGINE RPM SENSOR - R+R
11	PHASE TRANSFORMER ERRORS CHECK	All OK	Problems encountered	Operation
	Connect the diagnostic equipment and check that none of the following errors is present: P0011, P0014	Move on to Step 12	One or more of the errors indicated is present	Continue as described by the diagnostic equipment
12	CYLINDER COMPRESSION CHECK	All OK	Problems encountered	Operation
	Carry out the cylinder compression check Op. 0510A10 CYLINDER COMPRESSION - CHECK FOR LOOSE SPARK PLUGS OR INJECTORS	Move on to Step 14	Cylinder compression insufficient	Move on to Step 13
13	CHECK ON CAUSE OF INSUFFICIENT COMPRESSION	All OK	Problems encountered	Operation
	R/R head for valve leakage test Op. 1016C10 SINGLE CYLINDER HEAD - R.R. AND REPLACE GASKET Check condition of cylinders/piston rings	Move on to Step 14		Overhaul the head Op. 1016E10 SINGLE CYLINDER HEAD, REMOVED - OVERHAUL
			Cylinders/piston rings worn
			Cylinder head/cylinder block-crankcase matching faulty	Restore correct matching
14	TIMING CHECK	All OK	Problems encountered	Operation
	Check that the valve gear timing is correct Op. 0510A20 TIMING GEAR WITH BELT DRIVE - CHECK - CARRY OUT OPERATION WITH CAM COVER(S) REMOVED AND TAPPETS ADJUSTED AND CRANKSHAFT PULLEY DETACHED (IF NECESSARY)	Move on to Step 15	Valve gear timing not correct	Restore the correct valve gear timing
15	EXHAUST SYSTEM CHECK	All OK	Problems encountered	Operation
	Check that the exhaust circuit is not leaking, there are no loose connections, constrictions, deformations or damage	Move on to Step 16	Faults present	Restore the correct fastening of the problem components. Replace them if necessary
16	CHECK ON CORRECT OPERATION	All OK	Problems encountered	Operation
	Check the fault has disappeared	End of diagnosis	The fault persists	Contact the Technical Expert for further information on the problem

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