Compression pressures, checking

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2009 Audi S4, 2008 Audi S4, 2007 Audi S4, 2006 Audi S4, and 2005 Audi S4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools, testers and auxiliary items required

Fig 1: Identifying Spark Plug Wrench 3122 B

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Spark plug removal tool 3122 B

Fig 2: Compression Tester V.A.G 1763

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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.

Fig 3: Removing Fuse For Fuel Pump (FP) From Socket

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

Fig 4: Removing Rear Engine Cover

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Remove rear engine cover - arrows -.

Fig 5: Removing Front Engine Cover

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Remove front engine cover - arrows 1 and 2 -.

Fig 6: Removing Cover In Engine Compartment (Left Side)

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

Fig 7: Removing Coolant Hoses & Coolant Expansion Tank

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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.

Fig 8: Removing Bolt From Oil Dipstick Guide Tube At Cylinder Head

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Remove bolt - arrow - at oil dipstick guide tube.

NOTE:

Guide tube remains inserted in upper part of oil pan.

Fig 9: Removing Cover In Engine Compartment (Right Side)

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

Fig 10: Identifying Evaporative Emission Canister Purge Regulator Valve N80 And Air Duct

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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 → Rules for cleanliness .

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

Fig 11: Installing/Removing Fuel Hose To/From Connection On Fuel Rail Line

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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

Fig 12: Identifying Electrical Harness Connectors, Secondary Air Injection (AIR) Pump Hose, Air Guide Hose & Mass Air Flow (MAF) Sensor

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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 (AIR) pump.
Disconnect air guide hose - 4 - at Mass Air Flow (MAF) sensor.

Move wiring harness clear at air filter housing.
Remove clip and remove air filter housing with Mass Air Flow (MAF) sensor.

Fig 13: Removing Bolts On Left Cylinder Head, Disconnecting Electrical Harness Connectors & Removing Ignition Coils

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Remove bolts - 5 - and - 6 - on left cylinder head.
Disconnect electrical harness connectors - 1 to 4 -.
Remove ignition coils - arrows -.

NOTE:

Extractor T40039 can be used for removal.

Fig 14: Removing Bolts On Right Cylinder Head, Disconnecting Electrical Harness Connectors & Removing Ignition Coils

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Remove bolts - 5 - and - 6 - on right cylinder head.
Disconnect electrical harness connectors - 1 to 4 -.
Remove ignition coils - arrows -.

NOTE:

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.

NOTE:

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:

New bar positive pressure	Wear limit bar positive pressure	Difference between cylinders bar positive pressure
10.0 to 14.0	9.0	max. 3.0

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

Fig 15: Installing/Removing Fuel Hose To/From Connection On Fuel Rail Line

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Secure fuel hose to connection on fuel rail line. To do so, counter hold using an open-end wrench at each hex head - 1 - and - 3 - and tighten union nut - 2 - to 22 Nm.
Install sparks plugs →
- 01 - MAINTENANCE
- 01 - MAINTENANCE for MAINTENANCE PROCEDURES - CABRIOLET
.

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.

Torque specifications

Component	Nm
Wiring for ignition coils at cylinder head cover	5 * See note
Oil dip stick guide tube to cylinder head	10
Fuel supply line to fuel rail	22

* Insert using locking compound; locking compound .