Compression Pressure, Checking

WARNING: This page is about a different car, the 2015 Audi A7 Quattro, 2014 Audi A7 Quattro, 2013 Audi A7, and 2012 Audi A7. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Spark Plug Removal Tool3122B
Compression Tester KitVAG1763

Procedure

Engine oil temperature at least 30 °C (86 °F).
Battery voltage at least 12.5 V.

-- Remove the ignition coils, refer to IGNITION COILS WITH POWER OUTPUT STAGES, REMOVING AND INSTALLING .

-- Disconnect the connector -2- to the fuel injectors on the rear of the left cylinder head.

Fig 1: Disconnecting Connector To Fuel Injectors (Left Cylinder Head)

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Ignore items -1 and 3-.

-- Disconnect the connector -2- to the fuel injectors on the rear of the right cylinder head.

Fig 2: Disconnecting Connector To Fuel Injectors (Right Cylinder Head)

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Ignore items -1 and 3-.

-- Remove spark plugs with Spark Plug Removal Tool3122B.

-- Check the compression using the Compression Tester KitVAG1763.

NOTE:

For information on using the tester, refer to the Operating Instructions.

-- Have a second mechanic 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.

Compression Pressure	Pressure
New	11.0 to 14.0 bar (160 to 203 psi)
Wear limit	10.0 bar (145 psi)
Maximum difference between cylinders	3.0 bar (43 psi)

Assembling

Assemble in reverse order of disassembling. Note the following:

-- Install the spark plugs, refer to appropriate FLUID CAPACITY information .

-- Install the ignition coils, refer to IGNITION COILS WITH POWER OUTPUT STAGES, REMOVING AND INSTALLING .

-- Erase DTC entries which have occurred during the testing:

The Vehicle Diagnostic Tester is connected.

-- Select the mode.

-- Press the Go to button and select the "Function/component selection" and the following tree structures one after the other:

Drive
01 - On Board Diagnostic (OBD) capable systems
Simos Fuel Injection and Ignition
Functions
Readiness code