An apparatus and method for converting a fuel injected internal combustion engine normally operated with a conventional fuel such as gasoline to operate with an alternative fuel are disclosed. The apparatus comprises an alternative fuel introduction assembly having at least one alternative fuel injector, a temperature sensor, and an electronic translator. The electronic translator is adapted to receive conventional fuel injector control signals generated by an electronic control module, and to receive an output signal from the temperature sensor. The electronic translator then calculates an alternative fuel injector control signal to facilitate the supply of a required energy amount of the alternative fuel. The calculation is based upon the energy content of the alternative fuel, the temperature of the alternative fuel, and the flow and operating characteristics of the alternative fuel injector relative to a conventional fuel injector. Preferably, the alternative fuel is natural gas.