Audi Workshop Service and Repair Manuals

Checking compression Special tools and workshop equipment required

t  Spark plug socket and extension -3122 B-

t  Compression tester -V.A.G 1763-

t  Puller -T10094 A- Procedure l  Engine oil temperature min. 30 °C. l  Battery voltage at least 12.5 V. –  Switch off ignition. –  Remove fuse for fuel pump control unit -J538- from fuse holder C in fuse carrier 2 on right side of dash panel; for fuse assignment see → Current flow diagrams, Electrical fault finding and Fitting locations.

–  Pull off engine cover panel (front) -arrows- and remove towards front.

–  Remove bolts -1 and 3-. –  Release hose clip -2-, detach air pipe (top right) and remove air hose.

–  Unplug electrical connector -2-. –  Detach vacuum hoses -1-.

–  Unplug electrical connector -4-. –  Remove bolts -1 and 3-. –  Press release tabs and disconnect crankcase breather hoses -arrows-. –  Release hose clip -2- and disconnect hose at activated charcoal filter. –  Detach hoses.

–  Apply puller -T10094 A- to all ignition coils, pull out ignition coils and at the same time unplug electrical connectors at ignition coils for cylinders 1 ... 4. –  Remove spark plugs with spark plug socket and extension -3122 B-. –  Check compression pressure with compression tester -V.A.G 1763- (see → operating instructions for details of how to use tester). –  Have a 2nd mechanic press down the accelerator pedal completely and at the same time operate the starter until the pressure on the tester display no longer increases. –  Repeat procedure on each cylinder.

Compression pressure	bar
When new	10.0 … 15.0
Wear limit	9.0
Maximum difference between cylinders	3.0

Installation is carried out in the reverse order; note the following: –  Install spark plugs → Booklet819. –  Install air pipe (top right) → Chapter. –  Install air hoses with screw-type clips → Fig.. –  Faults are stored in the engine control unit because the fuse for the Motronic current supply relay -J271- was removed and the engine was started: Generate readiness code in Guided Functions using → Vehicle diagnostic tester.