fuel pump shut off

I just put a rebuilt 77 2.7 in my 75 911 and everthing was going good until I turned the key on to turn the motor over and get some oil flowing before I tried to start it.when I turned the key on I could hear the pump run but it didn't stop.I thought i needed to bleed it so i did that as per the haynes manual but the pump wants to keep running.should'nt it stop after running for just a second or two?I think that a couple of wires might be wrong but I need to know what makes the pump stop after building up preasure.