The Dynatek Fuel Injection Controller for the 2001 - 2005 Harley Davidson Softail & Dyna Models is a plug in module that offers 3 user selectable base fuel curves that are designed to improve engine operation and can be modified to suit a wide variety of modifications. These adjustments are made via 3 potentiometers that adjust the fuel curve in the proper ranges for the application. Fuel mixture can be enriched or leaned as required. The Dynatek FI Controller uses the factory connectors for easy installation and there is no PC required for tuning or adjusting the fuel curves. There are no modifications to the stock ECU and removing the Dynatek FI controller returns the vehicle to the factory configuration.