I have a 280SE German car, with a 3.5 liter gasoline engine and have lost power to my fuel pump. The pump also needs replacement. My question is can I run a switch to the pump with full time power or does the pump run on a as needed basis? Also does anyone know the presure output of this fuel pump? Alsp the pump is very expensive, is there a good alternative pump or a place to buy after market parts? Any help would be appriciated. Thanks Ruben