A heated fuel injector system and controller that includes a temperature sensing means to provide closed-loop control of a heating element heating fuel dispensed by a heated fuel injector. Closed-loop control provides more accurate temperature control of the heating element so that fuel heating is provided as quickly as possible while also protecting the fuel from being boiled and protecting the heated fuel injector from being damaged by excessive temperature. By monitoring how the signal from the temperature sensing means varies over time, fault conditions such as a lack of fuel flow, and fuel ethanol percentage may be detected.