the course of the discharge current the curve 14 shows the result of a calculation based on integration of the area beneath the curve in respect of the discharge current i in fig2 over the entire discharge duration the curve 15 shows the result of inductance calculation from the current variation in respect of time in accordance with the relationship i t imax exp u2212 r t l the curve 16 shows the result of a calculation based on integration of the area beneath the curve in respect of the discharge current i in fig2 over a defined time sub region of the entire discharge duration the position of the injector valve closed opened or partially opened can be clearly detected from all methods based on the evaluation of the discharge current configuration in respect of time with the quality of detection differing the curve 12 shows the best detectability curves 14 and 15 show the worst detectability which however is still sufficient fig4 relates to the possibility of being able to distinguish between a defective gas injector 1 and a gas injector 1 which is only worn by at least twice applying the method according to the invention fig4 shows the displacement travel of the iron core on the y axis the time t is plotted in milliseconds on the x axis the period of time 17 shows the opening duration of a defective gas injector 1 which per se is infinite limited here by the time duration of the measurement operation as in fact it never reaches the closed end position the period of time 19 shows the opening duration of a brand new properly functioning gas injector 1 the period of time 18 shows.