The invention relates to a method for determining the point in time of a predetermined open state of a fuel injector having a coil drive for an internal combustion engine of a motor vehicle. The method comprises the following steps: (a) Impacting the magnetic coil drive of the fuel injector with a first voltage pulse; (b) detecting a first temporal progression (20) of the current intensity of a current flowing through the coil drive; (c) impacting the magnetic coil drive of the fuel injector with a second voltage pulse; (d) detecting a second temporal progression (30) of the current intensity of the current flowing through the coil drive; (e) determining a differential progression (40) based on the detected first temporal progression (20) of the current intensity and the detected second temporal progression (30) of the current intensity, and (f) determining a point in time (T2) at which the differential progression (40) exhibits an extremum, wherein the determined point in time is the point in time of the predetermined open state. The invention further relates to a method for actuating a fuel injector, and to a device, to a motor control unit, and to a computer program.