Abstract: An add-on fuel injector control system and method for modifying a fuel injector pulse width for an electronically-controlled internal combustion engine is provided, which intercepts a pulse from an engine control unit (ECU) to a fuel injector, determines the optimal operational band, and either sends a modified or unmodified control signal pulse width to the fuel injector, depending on the band determination. The pulse width is increased by a total fuel adder. If the ECU control signal is determined to be in the auto-tune band, the controller modifies the output pulse width based on a comparison of current and previous values correlated to the rate of change of acceleration and whether the previous total fuel adder included an addition or subtraction of an auto-tune adder.

Abstract: An add-on fuel injector control system and method for modifying a fuel injector pulse width for an electronically-controlled internal combustion engine is provided, which intercepts a pulse from an engine control unit (ECU) to a fuel injector, determines the optimal operational band, and either sends a modified or unmodified control signal pulse width to the fuel injector, depending on the band determination. The pulse width is increased by a total fuel adder. If the ECU control signal is determined to be in the auto-tune band, the controller modifies the output pulse width based on a comparison of current and previous values correlated to the rate of change of acceleration and whether the previous total fuel adder included an addition or subtraction of an auto-tune adder.