18 · Diagnostics

Z53 Misfire error

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2002
Section: Examiner › Z53 Misfire error

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Fault diagnosisZ53 Misfire error

Z53 Misfire error

The tester indicates the error: Misfire

Step	Test procedure	Result	Action
0	PRELIMINARY CHECKS Connect the diagnostic equipment (Examiner or Examiner Plus) and transcribe the errors and environmental parameters. Check for the presence of the single error 'Misfire (general)'	OK	Incorrect selection of diagnostic procedure
		'Upstream lambda signal' error present	See table Z56 UPSTREAM LAMBDA SENSOR SIGNAL ERROR End of diagnosis
		'Mixture concentration' error present	See table Z50 MIXTURE STRENGTH ERROR End of diagnosis
		'Cylinder X misfiring' error present	See table Z54 MISFIRE ERROR IN ONE CYLINDER End of diagnosis
		Only the 'Misfiring (general)', 'Catalytic Converter' and/or 'Downstream lambda signal' errors are present	Move onto step 1
		Other errors are present	Identify and eliminate the cause of the fault. Move onto step 10
1	CHECKING CONTROL UNIT CIRCUIT Check the condition of the engine management unit wiring, connections and earth. No faults should be present	OK	Move onto step 2
1		Faults in the control unit electrical circuit	Restore the correct connections Wiring diagram E5030 PETROL ENGINES ELECTRONIC CONTROL If necessary, replace the parts involved Move onto step 10
2	CHECKING FUEL PRESSURE Check the fuel system pressure is correct Op. 0510C10	OK	Move onto step 3
2		Pressure not correct	Restore the correct pressure; if necessary, replace the faulty component. Move onto step 10
3	CHECKING FUEL QUALITY Check fuel quality, check no water or other impurities are present	OK	Move onto step 4
3		Impurities are present	Clean the tank and fill with new fuel Move onto step 10
4	CHECKING SIGNAL PLAUSIBILITY Checking plausibility of the MAP/debimeter sensor signalSee Test 1056BX MAP/flow meter signal plausibility	OK	Move onto step 5
4		The signal is not plausible	Replace the debimeter Op. 1056B09 Move onto step 10
5	CHECKING INLET AND EXHAUST SYSTEM SEAL Checking exhaust system, See Test 1072A Intake and exhaust system leakage check In particular, check there are no leaks downstream of the MAP/debimeter sensor also considering blow-by; canister circuit; brake servo vacuum pipes; injector o-rings	OK	Move onto step 6
5		Leaks are present	Restore exhaust system seal and replace the affected parts if necessary. Move onto step 10
6	CHECKING ENGINE PROBLEMS Check there are no basic engine problems. In particular, check: cylinder compression correct Op. 0510A10 ; correct engine timing correct rpm sensor position gap between rpm sensor and phonic wheel within permitted limits; visually for absence of faults on phonic wheel, such as broken or chipped teeth	OK	Move onto step 8
		Incorrect engine timing	Correct engine timing Op. 1032B10 Move onto step 10
		Incorrect rpm sensor positioning	Reposition sensor correctly Move onto step 10
		Phonic wheel defective	Replace the phonic wheel Op. 1024A28 Move onto step 10
		Insufficient compression	Move onto step 7
7	CHECKING CAUSE OF INSUFFICIENT COMPRESSION Carry out R/R on head to check the valve seal Check the condition of the cylinders/piston rings	OK	Move onto step 8
		Insufficient valve seal	Overhaul the cylinder head Op. 1016E10 Move onto step 10
		Cylinders/piston rings worn	Restore the seal Move onto step 10
8	CHECKS ON DRIVE CHAIN Check there are no fluctuations in the drive chain by carrying out a road test In particular: absence of clutch judder absenceof joint/bearing anomalies; absence of anomalies in engine blocks and mounts; correctly loaded suspension; correctly balanced tyres	OK	Move onto step 9
		Clutch juddering	Replace the clutch Op. 1810A20 Move onto step 10
		Anomalies in joints, bearings, blocks or mounts	Replace the affected parts Move onto step 10
		Front suspension unloaded	Replace damper Op. 4410A12 Move onto step 10
		Tyres not balanced	Balance the tyres Replace the anomalous tyres if necessary Move onto step 10
9	CHECK ERROR IN A SINGLE CYLINDER Connect the tester (Examiner or Examiner Plus) Check the presence of at least one 'Misfiring in cylinder X' fault'	OK	Incorrect selection of diagnostic procedure
		Error present in at least 1 cylinder	See table Z54 MISFIRE ERROR IN ONE CYLINDER referring to affected cylinders End of diagnosis
		Error not present in a specific cylinder	See table Z54 MISFIRE ERROR IN ONE CYLINDER referring to all cylinders in succession End of diagnosis
10	DELETE AND CHECK ERROR Cancel errors in control unit using tester Carry out a road test and check that error does not recur	OK	Move onto step 11
10		The fault persists	Move onto step 11
11	CHECKING CORRECT OPERATION Check that the fault is no longer present	OK	Incorrect selection of diagnostic procedure
11		Fault persists	Incorrect selection of diagnostic procedure

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Parts & tools for this job For 2000 Alfa Romeo 147

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