Electronically controlled variable delivery pumps produce output based upon a control signal generated by an electronic control module. The electronic control module includes programming that acknowledges that each pump may have performance characteristics that deviate from a hypothetical nominal pump. Actual pump performance characteristics are then programmed into the electronic control module so that pump control signals are customized or electronically trimmed to suit the performance characteristics of that individual pump. The performance characteristics of the individual pump are gained through testing. The electronic pump trimming strategy of the present invention is particularly applicable to hydraulic systems, such as fuel injection systems, used in internal combustion engines.