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Home >> Audi >> 2007 >> RS4 Quattro Sedan (8EC) V8-4.2L (BNS) >> 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

• Hose Clamps Up to 25 mm Diameter (3094)

• Spark Plug Removal Tool (3122 B)

• Compression Tester (V.A.G 1763)

• Puller (T40039)

Procedure

• Engine oil temperature min. 30 °C

• Battery voltage min. 12.5 V.

- Switch off ignition.

- Disconnect electrical connector at Engine Speed (RPM) Sensor (G28) - arrow - at left of transmission by bending heat shield to side slightly.





- Remove cover - 1 - in engine compartment (left side).





- Clamp off coolant hose - 2 - using Hose Clamps Up to 25 mm Diameter (3094) and disconnect from coolant expansion tank.





- Seal the connection using a plug that fits.

- Remove coolant expansion tank - arrow -.

- Disconnect electrical wire from Engine Coolant Level (ECL) Warning Switch (F66) at bottom on coolant reservoir and set aside coolant reservoir with coolant hose - 1 - connected.

- Remove oil dipstick - 1 - from guide tube.





- Remove bolts - 2 - and - 3 -.

- Disconnect electrical harness connectors at ignition coils.

- Press electrical wiring harness to side.

- Remove the bolts - arrows -.





- Remove the air duct - 1 - and - 2 -.

- Remove the bolts - 1 - and - 2 -.





- Disconnect electrical harness connectors at ignition coils.

- Press electrical wiring harness to side.

- Remove all ignition coils using Ignition Coil Puller (T40039).





- Using Spark Plug Removal Tool (3122 B), remove spark plugs.

- Check compression using Compression Tester (V.A.G 1763 ).

• Using tester => operating instructions.

- Have a second technician press accelerator pedal completely and at the same time operate starter long enough until pressure increase no longer appears on tester.

- Repeat procedure on each cylinder.





Assembling

Assembly is in reverse order of removal, note the following:

- Install the spark plugs.

- The engine control modules have stored a fault because the connectors were disconnected. Perform "generate readiness code" in " Guided Functions".

Tightening Specifications




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