Warning! The fuel system is under pressure. Observe the relevant safety regulations! Before opening the system, cover the connection with a rag. Release the pressure by carefully loosening the connection.
1. Removal: Remove the rear engine cover (arrows).
Removing the engine cover
2. Remove the screws on the mounting plate for the solenoid valves (arrow).
Screws on mounting plate for solenoid valves
3. Disconnect the connectors from all valve injectors.
4. Remove vacuum hose 3 from the fuel pressure regulator.
5. Unscrew the fuel distributor from the variable-length intake manifold.
Disconnecting the fuel distributor from the intake manifold with variable tract length
6. If it is necessary to change the fuel distributor, disconnect the supply line 2 and the return line 1. Otherwise, remove the fuel distributor together with the injectors evenly upwards from the intake manifold and place it on a clean cloth at the rear of the engine compartment.
7. After this, remove the spring clip at the junction of the injector and the fuel distributor and remove the injector (the nozzle is simply inserted into the distributor).
8. When installing the injectors, which is done in the reverse order, be sure to replace all O-rings, lightly lubricate the rings with clean engine oil. When replacing the front O-ring, do not remove the plastic cap from the injector head under any circumstances! The ring must be removed through the cap.
9. Push the injectors in the correct position vertically into the fuel distributor until they stop and secure with spring clamps. Check that the clamps are seated correctly on the distributor and injectors!
10. Install the fuel distributor with the injectors attached to it on the intake manifold and press it evenly until it stops.
[A link to the original source is available on the website: AudiManual]