Compression, Checking

WARNING: This page is about a different car, the 2015 Audi Q7, 2014 Audi Q7, and 2013 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.

Special tools and workshop equipment required

Compression Tester KitVAG1763 with Compression Tester Kit - Adapter 8VAG1763/8

Procedure

Fig 1: Identifying Engine Cover -Arrows-

Courtesy of AUDI OF AMERICA, LLC

Engine oil temperature approximately 80 °C (176 °F)
Battery voltage at least 12.5 V.

-- Carefully pull the engine cover off the four retaining pins one after the other -arrows-.

-- Disconnect the connectors on all of the glow plugs.

-- Disconnect the connector -arrow- on the Fuel Pressure Regulator Valve -N276- from the cylinder bank 1 (right) fuel rail.

Fig 2: Fuel Pressure Regulator Valve -N276-

Courtesy of AUDI OF AMERICA, LLC

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

-- Remove all glow plugs. Refer to GLOW PLUGS .

Fig 3: Identifying Valve Stem Seal

Courtesy of AUDI OF AMERICA, LLC

-- Install the Compression Tester Kit - Adapter 8VAG1763/8 in place of the glow plugs and connect the Compression Tester KitVAG1763.

Fig 4: Identifying Compression Tester Kit - Adapter

Courtesy of AUDI OF AMERICA, LLC

NOTE:

Information on using the tester. Refer to the Operating Instructions.

-- Have a second technician operate the starter until the test stops showing an increase in pressure.

-- Repeat procedure on each cylinder.

Compression Pressure	Bar Pressure
New	28 to 33 bar (406 to 478 psi)
Wear limit	21 bar (305 psi)
Maximum difference between cylinders	5 bar (72.5 psi)

Assembling

Assemble in reverse order of disassembling. Note the following:

-- Install the glow plugs. Refer to GLOW PLUGS .

-- There will be entries stored in the engine control module Diagnostic Trouble Code (DTC) memory if the engine was started while the connectors were disconnected: Check DTC memory in OBD . Refer to Vehicle Diagnostic Tester.