The pressure difference between the individual cylinders must not exceed 3.0 bar. If one or more cylinders have a pressure that differs from the pressure in other cylinders by more than 3.0 bar, this indicates a leak in the cylinder head gasket, damaged valves, worn piston rings or the working surface of the cylinders. If the wear limit is reached, the engine must be repaired or replaced.
Order of execution
1. To check the compression, the temperature of the engine oil must be at least +30°C. The oil filter is at palm temperature. If the temperature is lower than specified, the engine must be warmed up. The engine temperature must not be too high, otherwise the threads in the cylinder head may be damaged when the spark plugs are removed.
2. Switch off the ignition.
3. Remove all spark plugs.
4. Remove the fuel pump fuse.
5. Engines 1.6 l: Disconnect the injector connector from both outer cylinders.
6. Engines 1.6: Disconnect the ignition output stage connector. The output stage is connected between the control unit and the ignition coils.
7. Turn the engine over with the starter to expel the carbon and soot.
Warning: Place the manual transmission in neutral and apply the parking brake.
Warning: When cranking the engine, do not lean over it. There is a risk of injury from ejection of soot.
8. Screw or press the compression gauge into one of the spark plug holes.
9. Ask an assistant to press the gas pedal and hold it in this position during the entire test.
10. Crank the engine about 8 revolutions until the gauge shows no more pressure spikes.
11. Check all cylinders in order and compare the values obtained with the required value.
12. Replace the spark plugs when finished.
13. Reconnect the output stage connector (engines 1.6 l).
14. Engines 1.6 l: Connect the plug connections at the external injectors.
Warning: Disconnection of plug connections can cause faults in the engine control unit. It is recommended that they be removed by an AUDI workshop as soon as possible.
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