Should I add a fuel pump to my TDI?
Most diesel engines have an inline pump before the injection pump, called the lift pump. The TDI injection pump was designed with a low pressure lift pump built into the unit. This may be okay at idle and under mild throttle, however under hard acceleration or fuel demand, the fuel pump is starved for fuel. Having an inline electric fuel pump helps with performance and also helps prime the fuel system. It can also help with the nasty starts in the morning caused by back feeding in the injection pump. Remember, to use a quality built lift pump. Also, remember that most fuel pumps are designed as pushers not pullers, therefore, they are located closer to the fuel tank rather than the injection pump.