Audi Workshop Service and Repair Manuals

Checking compression

Special tools and workshop equipment required

t	Spark plug socket and extension -3122 B-

t	Compression tester -V.A.G 1763-

t	Spark plug connector pliers -V.A.G 1922-

Test requirements l  Engine oil temperature at least 30 °C l  Battery voltage at least 12.5 V

Test sequence –  Switch off ignition. –  Lift off engine cover -arrows-.

–  Unbolt coolant expansion tank -arrow-. –  Unplug electrical wire for coolant shortage indicator switch -F66- at bottom of expansion tank and move expansion tank to one side with coolant hoses -1- and -2- attached.

–  Detach electrical connector -1- at output stage for ignition coil -2-. –  Detach electrical connectors at injectors. –  Detach spark plug connectors using spark plug connector pliers -V.A.G 1922-. –  Remove spark plugs with spark plug socket -3122 B-. –  Test the compression pressure with the compression tester -V.A.G 1763-.   Note Using the compression tester → operating instructions. –  Have a 2nd mechanic press down the accelerator pedal completely and simultaneously operate the starter until the pressure no longer increases on the tester display. Compression pressure

New pressure in bar	Wear limit bar	Permissible difference between cylinders bar
10.0 … 13.0	7.0	3.0 (maximum)

–  Install spark plugs. –  Finally, interrogate and erase the engine control unit fault memory as faults are stored when the fuses are removed → Vehicle diagnosis, testing and information system VAS 5051. Tightening torque

Component	Nm
Spark plugs in cylinder head	30