PPE Dual Fueler Kit for 2004-2005 Duramax LLY is driven by a second Bosch CP3 Fuel Pump, Belt Pulley and controlled by a sophisticated Microprocessor Module, this kit offers TWICE as much pumping capacity while increasing fuel pressure and horsepower. Adding a belt driven CP3 Pump Kit to your stock fuel system reduces drive load on the internal gear driven CP3 pump, increasing pump reliability. Both pumps work together, each delivering half the total volume of fuel required, effectively sharing the fuel delivery load. In the event of a pump failure, PPE’s electronic controller will automatically switch full fuel delivery to the other remaining functional pump. The Dual Fueler Kit will not produce more fuel pressure than the ECU requests; it will only increase fuel volume.