Audi Workshop Service and Repair Manuals

Checking compression Special tools and workshop equipment required

t  Compression tester -V.A.G 1763- with adapter -V.A.G 1763/8-

Procedure l  Engine oil temperature approx. 80 °C. l  Battery voltage at least 12.5 V. –  Carefully pull engine cover panel off four retaining pins one after the other -arrows-. –  Unplug electrical connectors on all glow plugs.

–  Unplug electrical connector -arrow- at fuel pressure regulating valve -N276- on fuel rail (cylinder bank 1, right-side). –  Briefly start engine to relieve fuel pressure in fuel rail.

–  Remove all glow plugs → Rep. gr.28.

–  Screw in adapter -V.A.G 1763/8- in place of the glow plugs and connect compression tester -V.A.G 1763-.   Note Using the compression tester → Operating instructions. –  Have a 2nd mechanic operate starter until tester shows no further pressure increase. –  Repeat procedure on each cylinder.

Compression pressure	bar
When new	28 … 33
Wear limit	21
Maximum difference between cylinders	5

Assembling Installation is carried out in the reverse order; note the following: –  Install glow plugs → Rep. gr.28. –  Faults are stored in event memory of engine control unit because electrical connectors were unplugged and the engine was started: Interrogate event memory in Vehicle self-diagnosis → Vehicle diagnostic tester.