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)

Test Conditions





• Engine oil temperature min. 30 °C

• Battery voltage at least 12.5 V

Test Sequence

- Switch off ignition.

- Remove fuse for Fuel Pump (FP) from socket - 28 -.

- Remove rear engine cover - arrows -.





- Remove front engine cover - arrows 1 and 2 -.





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





- Remove coolant expansion tank - arrow -.





- Disconnect electrical wire from Engine Coolant Level (ECL) Warning Switch (F66) and set aside coolant reservoir with coolant hoses - 1 - and - 2 - connected.

- Remove bolt - arrow - at oil dipstick guide tube.





• Guide tube remains inserted in upper section of oil pan.

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





- Disengage Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80) - 1 - from air guide.





- Remove bolts - arrows -.

- Remove air duct - 2 -.

CAUTION!
Note rules of cleanliness for working on the fuel injection system. Refer to => [ Clean Working Conditions ] Clean Working Conditions.

CAUTION!
Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

- Remove fuel hose from connection on fuel rail pipe. To do so, counterhold using an open-end wrench at hex head - 1 - and - 3 - and remove union nut - 2 -.





- Disconnect electrical harness connector - 2 - from Evaporative Emission (EVAP) Canister Purge Regulator Valve ( N80).





- Disconnect electrical harness connector - 3 - at Mass Air Flow (MAF) Sensor (G70).

- Disconnect hose - 1 - to Secondary Air Injection pump.

- Disconnect air guide hose - 4 - at Mass Air Flow sensor.

- Move wiring harness clear at air filter housing.

- Remove clip and remove air filter housing with Mass Air Flow sensor.

- Remove bolts - 5 - and - 6 - on left cylinder head.





- Disconnect electrical harness connectors - 1 to 4 -.

- Remove ignition coils - arrows -.

• Extractor (T40039) can be used for removal.

- Remove bolts - 5 - and - 6 - on right cylinder head.





- Disconnect electrical harness connectors - 1 to 4 -.

- Remove ignition coils - arrows -.

• Extractor (T40039) can be used for removal.

- Using spark plug removal tool (3122 B), remove spark plugs.

- Open throttle valve completely.

- Check compression using compression tester (V.A.G 1763 ).

• Using the compression 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.

Compression pressure:





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

- Secure fuel hose to connection on fuel rail pipe. To do so, counterhold using an open-end wrench at each hex head - 1 - and - 3 - and tighten union nut - 2 - to 22 Nm.





- Install sparks plugs.

Faults are saved in the ECM when the electrical connectors are disconnected:

- Connect Vehicle Diagnosis, testing & info. system (VAS 5051B).

- Start "Guided Functions" operating mode.

- Generate readiness code in ECM.

Tightening Specifications





* Insert using locking compound.