Skoda Workshop Service and Repair Manuals > Octavia Mk2 > Drive unit | 1.6/85 kW FSI Engine | Engine cylinder head, valve gear | Cylinder head - part 2

Testing the compression

Special tools and workshop equipment required

t	Compression tester, e.g. -V.A.G 1763-

Test condition

Engine oil temperature at least 30 °C

Test sequence

–	Remove engine cover with air filter → Chapter.

–	Remove the ignition coils and spark plugs → Chapter.

–	Open lid of fuse carrier in the engine compartment and unplug the fuse for Motronic current supply relay -J271- → Current flow diagrams and Fitting locations.

Note

t	The fuse assignment is different depending on the model year.

t	Removing fuse interrupts the voltage supply of the injection valves and ignition coils.

–	Check compression pressure using the compression tester.

Note

–	Operate starter until the tester no longer indicates a pressure rise.

Compression readings

New engine	Wear limit	Difference between cylinders
1...1.5 MPa (10...15 bar)	0.7 MPa (7 bar)	0.3 MPa (3 bar)

If the specified values are not reached, test the combustion chamber for leaks → Chapter.

–	Screw in the spark plug with spark plug wrench and then tighten fully to 25 Nm.

Further installation occurs in reverse order.

–	Interrogate fault memory, rectify any faults existing and erase the fault memory → Vehicle diagnosis, testing and information system VAS 5051.

After deleting the fault memory of the engine control unit the readiness code must be re-generated.

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