What do this do, close to the fuel pump (Opel Kadett GSi16v). Do i need it?

Hello

Called in German: "Membrandämpfer" or "Pulsationsdämpfer".

Hi,

It is a diaphragm or pulsation damper.

Technical background of this damper is to reduce/ eliminate the pulsation from the injectors (caused by mechanical hard opening/closing) in the fuel circuit, that means the fuel system pressure peaks are smoothed. It's a protection device for the fuel pump. If you remove the damper, the lifetime of your pump will be decrease ..