Although injection timing accuracy is sensitive to rail pressure, injection quantity of the fuel injection event is strongly a function of rail pressure. Thus, delivery accuracy of each injection event depends strongly upon the accuracy of a rail pressure estimate used in determining the injection control signal characteristics. These injection control signal characteristics include a calculated delay between a start of control current and start of injection, as well as the duration of the control signal. The present invention takes a rail pressure measurement substantially before an injection event, and then utilizes a rail pressure predictor model to predict what the rail pressure will be at each injection event in a succeeding injection sequence. This estimated rail pressure is then used as the means for determining the fuel injection control signal characteristics for that succeeding injection event.