The article discusses results of the laboratory experiments in which fuel injectors used in indirect injection internal combustion engines were tested. During the experiments, numerous dosing cycles of the injectors were performed while changing the control parameters, due to which, the dosing characteristics were developed and influence of applied parameters on the resultant fuel flow determined. Simultaneously, the voltage and electric current waveforms in the injector coil were recorded, due to which finding links between the electric current characteristics and the determinants of the injector work was possible. The investigation has shown that parameters of electric current constitute a precise criterion for assessing the operation of the solenoid valve, because fuel flow is created due to the work ofelectric current. Thus, by observing the changes in the current flowing through the valve coil,it is possible to monitor precisely the correctness of the process of opening the flow and the electric current intensity, at which the flow began and to determine the mechanical quantities such as fuel dose and pressure. As a result, a characteristic is developed, that provides the links between the fuel pressure and the electric current at the point of lifting the needle, which is quite a novel approach. Such a characteristic can be used in diagnostics and control of fuel injectors as well as all kinds of electromagnetic valves