Note: To perform the following tasks, it is necessary to use special devices, control and measuring instruments, as well as auxiliary means:
- Hinged wrench No. 10(3220).
- Compression pressure measuring device, eg (VAG 1763).
- Adapter (VAG 1763/8).
Note: Condition for control:
- Oil temperature minimum 80°C.
- Battery voltage is at least 12.5 V.
1. Remove the top decorative cover (see the relevant section in this chapter).
2. Disconnect the fuel pressure regulating valve (N276) wiring harness connector (arrow) on the fuel rail as shown in the figure below.
3. Start the engine briefly to allow the pressure in the fuel rail to drop.
4. Remove the glow plugs.
5. Screw the adapter into the threaded hole of the glow plug at the cylinder being tested (VAG 1763/8) and connect a compression measuring device (VAG 1763).
6. Ask the second mechanic to turn on the ignition and starter. Turn the engine with the starter until the pressure on the compression gauge increases. Stop the engine when the pressure stops increasing.
7. Gradually measure the compression pressure in all engine cylinders.
| Compression pressure values | Pressure |
| New engine | 2.5...3.1 MPa (25.0...31.0 bar) |
| Wear limit | 1.9 MPa (19.0 bar) |
| Max. permissible deviation between individual cylinders | 0.5 MPa (5.0 bar) |
8. Installation is carried out in the reverse order of removal. Observe the following instructions:
- Install the glow plug for the corresponding cylinder.
- Erase the engine control unit fault memory and reset the memory contents.
Note: After resetting the engine control unit fault memory, a new readiness code must be generated.