Fuel injector

Fuel injector (10) having a body comprising a plurality of coaxial cylindrical members (20, 22, 24) pressed against one another by an injector nut (14). A thin volume (V1, V2) extending between the nut (14) and the injector body is in fluid communication with the low-pressure return circuit of the injector (10). The injector (10) is provided with an insulation means (76) capable of reducing pressure waves propagating in fuel located in said thin volume (V1, V2).