Main Pump

The fuel pump, an electrically driven roller-type pump, feeds fuel under pressure to the continuous injection system. Pump operation begins when the starter motor engages or the engine is running.
As the pump motor spins, the rollers are forced outward by centrifugal force and ride against the eccentrically shaped pump chambers. Fuel is drawn into the cavities between the rollers and forced outward to the line under pressure.
If pump output exceeds system requirements, creating excess pressure, a built-in relief valve opens, allowing the fuel to be circulated around the pump. A check valve on the outlet side prevents fuel from flowing back when the pump stops operating.