D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE - Alfa - 156 - eLearn

3233018 - D05 ENGINE DOES NOT PRODUCE BEST PERFORMANCE

The engine runs smoothly at medium-low speeds, but does not reach iits usual maximum performance (both in terms of speed and acceleration)

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the state of the spark plugs and leads the condition of the air intake circuit for possible obstruction of the catalyzer and other exhaust pipes for any obstacles to the complete accelerator pedal travel	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
			Air intake circuit component damaged	Replace the component (see Assembly 1048A)
			Catalyzer obstructed	Replace the catalyzer Op. 1080B62
			Exhausts obstructed	Replace the component involved (see Assembly 1076B)
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	ACCELERATOR CHECK	All OK	Problems met	Operation
1.6 TS 1.8 TS [d]	Check the accelerator cable. In particular, check the: condition of the cable correct sliding of the cable in the sheath correct fixing of the sheath	Continue to Step 3	Accelerator cable faulty	Renew the accelerator cable Op. 1068A30
2.5 V6	Check that the accelerator pedal potentiometer is correctly calibrated	Continue to Step 3	Potentiometer setting incorrect	Restore the operation of the potentiometer
3	CHECK ON FUEL PRESSURE	All OK	Problems met	Operation
	Check the fuel supply pressure Op. 0510C10	Continue to Step 4	Pressure not correct	Replace the fuel pump assembly Op. 1056B70
4	CHECK ON CYLINDER COMPRESSION	All OK	Problems met	Operation
	Carry out the cylinder compression test Op. 0510A10	Continue to Step 5	Compression values not correct	Restore the correct cylinder compression, for example, checking the seal of the injectors Op. 1056B70 and the cylinders (see OVERHAULING ENGINE, Subassembly 1004)
5	CHECK ON TIMING	All OK	Problems met	Operation
	Check that the engine timing is correct	Continue to Step 6	Timing not correct	Restore the correct engine timing Op. 1032B14
6	TIMING VARIATOR CHECK	All OK	Problems met	Operation
1.6 TS 1.8 TS [d]	Using the diagnostic equipment (Examiner or other instruments) carry out the active diagnosis of the variable valve timing system	Continue to Step 7	Variable valve timing connection faulty	Renew the connection between the variable valve timing system and the control unit, ( See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT )
			Variable valve timing faulty	Replace the variable valve timing system
			Variable valve timing electro-magnet faulty	Replace the electro-magnet Op. 1056B48
2.5 V6		Continue to Step 7
7	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'