Hi guys I have a 2008 cummins isx 550. I was complaining about fuel mileage and lack of power to a friend and he told me about a little device that plugs into the back of the fuel pump and one lead plugs to the Wiring from the ECM. In series from ECM to fuel pump. We borrowed this little box from another cummins owner and it makes quite the difference in fuel mileage and pulling power. Easily out pulls the other 08 isx we have. Same specs. And saves about 5-7% fuel. Was wondering what this device actually does to the motor or ecm. Are we doing any harm to the motor, it is still under warranty. I have not taken this box apart yet to see whats inside! No cel, and it feels like it has more torque as well. Thanks Ken.