to carburetor systems which have an arrangement for limiting the maximum amount of fuel to be supplied and which can be influenced by an altitude correction signal in such a manner that the maximum amount of fuel to be supplied can be reduced with increasing altitudes above sea level during the operation of the motor vehicle fig2 a and 2b show an embodiment specifically relating to an electric fuel injector however it is to be noted that the invention should not be limited to such a fuel injector fig2 a illustrates an impulse generating circuit s which is dimensioned in such a way that upon triggering by a speed synchronous signal an impulse of predetermined duration is provided which impulse acts in an injector as the before mentioned t pmax and corresponds to the maximum amount of fuel to be supplied to a combustion engine the circuit s can preferably be developed as a monostable multivibrator and receives triggering impulses by a trigger circuit as which is connected to the circuit s for time synchronizing the generation of the t pmax impulses by the circuit s the received triggering impulses are either identical with the trigger impulses which cause the generation of the fuel injection impulse t p in the electric control.