Abstract: An adapting mechanism for controlling the speed of a variable speed fuel pump in a returnless fuel delivery system includes a demand sensor, feedforward fuel pump values, adaptive adjustments corresponding to the feedforward values, a pump controller which controls the speed of the fuel pump, a timer, a steady demand indicator, a flow error accumulator, and an adjustor. The system chooses a feedforward value which corresponds to the engine's fuel demand and combines it with the corresponding adaptive adjustment to drive the fuel pump. The system monitors the average flow error over a time interval throughout which the fuel demand is substantially steady and modifies the adaptive adjustments to reduce any error offsets beyond a predetermined acceptable level.