Abstract: A fuel injection system that includes an electronic controller that senses engine speed, calculates energy required by an engine existing control unit based upon a signal sent to one or more diesel injection pressure and timing actuators and a plurality of gaseous fuel injectors that respond to commands from the electronic controller and inject gaseous fuel through an injection tube installed in an intake adapter plate fixed between an intake manifold and an engine block. The fuel injection system also includes an on and off switch assembly equipped with a self-diagnostic capability that lights an LED light when a fault in the port injector system is sensed and a blended fuel injector control unit installed between an ECM and a plurality of diesel fuel injectors.