A Fastening element has a carrier. A first pair of prongs branches off a first side face of the carrier designed to be in a mechanical engagement with a protrusion of a injector cup. A second pair of prongs branches off a second side face of the carrier. The second pair of prongs is designed to retain a fluid injector and to couple mechanically to a first protrusion of the injector. A pair of pins branches off a respective prong from the second pair of prongs at a respective inner side face of the respective prong. The pins are arranged opposed to each other and in a given distance from each other and they are designed to be in a mechanical engagement with the fluid injector. A clamping device being designed to couple mechanically with the fluid injector cup and to exert a repelling force on the fluid injector cup.