Compression, Checking

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The compression can be checked with the following testers.

Vehicle Diagnostic Tester
Compression Tester Kit: V.A.G 1763
Pressure-Loss Tester: VAS 522 001
CO2 Coolant Tester: VAS 531 009

Procedure using Vehicle Diagnostic Tester:

Special tools and workshop equipment required

Vehicle Diagnostic Tester

-- Connect the Vehicle Diagnostic Tester.

-- Switch the ignition on.

-- Select the engine electronics .

-- Select subsystem - constraints .

-- Select compression test from the list.

If a cylinder is noticeable, check the compression using the Compression Tester Kit: V.A.G 1763 .

Procedure using the Compression Tester Kit: V.A.G 1763 :

Special tools and workshop equipment required

Compression Tester Kit: V.A.G 1763 with Compression Tester Kit - Adapter 8: V.A.G 1763/8

Fig 1: Compression Tester Kit VAG 1763
Courtesy of AUDI OF AMERICA, LLC

Engine oil temperature at least 30 °C.
Battery voltage at least 12.5 V.

-- Remove the engine cover. Refer to ENGINE COVER, REMOVING AND INSTALLING .

-- Disconnect the connector on the Fuel Pressure Regulator Valve -N276- -2-.

Fig 2: Identifying Connector On Fuel Pressure Regulator Valve

Courtesy of AUDI OF AMERICA, LLC

-- In order to reduce the fuel pressure in the high pressure reservoir, start the engine briefly.

-- Remove all glow plugs. Refer to GLOW PLUG, REMOVING AND INSTALLING .

-- Install the Compression Tester Kit - Adapter 8: V.A.G 1763/8 in place of the glow plug and connect the Compression Tester Kit: V.A.G 1763 .

Fig 3: Identifying Compression Tester Kit

Courtesy of AUDI OF AMERICA, LLC

-- Have a second technician operate the starter until the tester stops displaying a pressure increase.

-- Repeat the procedure on each cylinder.

Compression pressure	bar pressure
New	25.0 to 31.0
Wear limit	19.0
Maximum difference between cylinders	5.0

TIP:

If the test with the Compression Tester Kit: V.A.G 1763 does not lead to a clear result there are two additional tests.

In addition to the compression test a pressure test can be performed with the Pressure-Loss Tester: VAS 522 001 . The procedure for this is described in the operating instructions for the Pressure-Loss Tester: VAS 522 001 .
As an additional test the CO2 content in the coolant expansion tank can be measured. A raised CO2 content in the cooling system indicates a leak between the combustion chamber and the cooling system. The CO2 content can be determined using the CO2 Coolant Tester: VAS 531 009 . The procedure for this is described in the operating instructions of the CO2 Coolant Tester: VAS 531 009 .

Assembling

Assemble in the reverse order of removal. Note the following:

-- Install all glow plugs. Refer to GLOW PLUG, REMOVING AND INSTALLING .

-- Install the engine cover. Refer to ENGINE COVER, REMOVING AND INSTALLING .

-- Delete DTC entries which were generated during testing using the Vehicle Diagnostic Tester.