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Home >> Audi >> 2012 >> A8 Quattro Sedan (4H2) V8-4.2L (CDRA) >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
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Compression Check: Testing and Inspection






Compression, Checking

Special tools, testers and auxiliary items required

• Spark Plug Removal Tool (3122 B)

• Compression Tester (V.A.G 1763)

Procedure

• Engine oil temperature at least 30 °C (86 °F).

• Battery voltage at least 12.5 V.

- Remove the rear noise insulation - 2 -..






- Disconnect the electrical connector - 2 - on the engine speed (RPM) sensor (G28).






• Ignore - 1 -.

- Remove ignition coils.






- Remove the spark plugs with (3122 B).

- Check compression pressure using the (V.A.G 1763).

• Using tester see operating instructions.

- Have a second technician press the accelerator pedal down all the way while operating the starter until the pressure increase is no longer displayed on the tester.

- Repeat procedure on each cylinder.






Assembly is performed in reverse order of removal, noting the following:

- Install the rear noise insulation..

- Install spark plugs. Refer to Maintenance Procedures.

- Install ignition coils.

- If the connectors were disconnected and the engine was started, then malfunctions have been stored in the engine control module DTC memory. Generate readiness code in Guided Functions, see vehicle diagnosis tester.

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