Volkswagen Workshop Service and Repair Manuals > Golf Mk4 > Power unit | 6-cylinder injection engine | Engine cylinder head, valve gear | Cylinder head (engine codes AQP, AUE)

Checking compression

Special tools and workshop equipment required

t	Torque wrench -V.A.G 1331-

t	Compression tester -V.A.G 1763-

t	Spark plug socket and extension -3122 B-

t	Assembly tool -T10118-

Test prerequisite

l	Engine oil temperature at least 30 °C

l	The battery voltage must be at least 11.5 V.

Test procedure

–	Remove engine cover.

–	Unplug 5-pin connector from ignition transformer -arrow-.

–	Remove spark plug connectors and unclip ignition cables.

–	Remove fuse No. 29 from fuse holder.

Removing fuse 29 interrupts the voltage supply to the injectors.

–	Spark plug socket and extension -3122 B- is used in all engines to unscrew spark plugs.

–	Check compression using compression tester -V.A.G 1763-.

Note

Using compression tester ⇒ Operating instructions.

–	Operate starter until tester shows no further pressure increase.

Compression pressures:

New: 10…13 bar

Wear limit: 7.5 bar.

Maximum permissible difference between all cylinders: 3 bar

–	Then reinstall spark plugs and ignition coils with output stage → Chapter.

After the test has been completed:

–	Connect Vehicle diagnosis, testing and information system -VAS 5052-.

–	Carry out vehicle system test → Vehicle diagnostic tester„Guided fault finding“.

–	Finish the vehicle system test so that any fault entries stored during assembly can be deleted automatically.

–	Generate the readiness code in combination with a road test.

Observe applicable safety precautions during road test.

–	Carry out road test.

–	Then carry out vehicle system test again and rectify any faults which may have occurred.

Volkswagen Workshop Service and Repair Manuals