Compression Check: Testing and Inspection

Compression pressures, checking

Special tools, equipment, testers, measuring instruments and auxiliary items required





^ 3122B Spark plug wrench
^ T10112 Removal tool
^ VAG1331 Torque wrench (5...50 Nm)
^ VAG1763 Compression tester

Requirements
^ Engine oil temperature must be at least 30°C.
^ Voltage supply OK.
^ All electrical consumers, e.g. lights and rear window defogger must be switched off.
^ If the vehicle is equipped with air conditioning, this must be switched off.
^ On models with an automatic transmission selector lever in position "P" or "N"





Work sequence
^ Remove engine cover.
^ Disconnect 6-pin connector from ignition coil with final output stage (arrow).





Engine code AEG.





Engine codes AVH, AZG, BDC, BEV, BGD
^ Pull fuse No. 32 out of fuse holder.

Note: Removing the fuse interrupts the voltage supply to the injectors.

^ Disconnect connectors for outer injectors.
^ Disconnect spark plug connectors with tool T10012
^ Remove spark plugs with spark plug wrench 31 22B.
^ Check compression pressures using compression tester VAG1763 and adapter VAG1763/6.

Note: To use the compression tester; Refer to Operating instructions.

Vehicles without EPC
^ Have a second technician fully depress accelerator pedal.

Continuation for all models
^ Have a second technician operate starter motor.
^ Operate starter until tester shows no further pressure increase.

Compression pressure values
New: 10...13 bar
Wear limit: 7.5 bar
Permissible difference between all cylinders: 3 bar
^ Adapt (match) engine control module to throttle valve control module; Refer to Adapting components and functions
^ If fault memory has been erased or engine control module was disconnected from permanent positive, respective components must be adapted to engine control module,and readiness code generated again.