An improved fuel injection device for internal combustion engines comprising a slidable (pilot) valve instead of a needle valve principle. The valve does not comprise a seat, so, even in the case of a spring-loaded embodiment of the valve there is no risk of hammering of the valve on a seat with the pertaining generation of noise.The improved fuel injector allows a larger nozzle diameter and, therefore, a larger number of nozzle holes, if required or deemed useful.For rotating embodiments of the fuel injector, the valve or at least its spring, in the case of a spring-loaded embodiment of the valve, can be located in the static section of the rotating fuel injector, thus eliminating the balancing problem of prior art rotating fuel injectors which comprise a spring in the rotating section.