Why do I have to prime the pump?

[Dave <dnevin@KUHUB.CC.UKANS.EDU>]

I'm making good progress on resolving my no-start 87 4Kq.
I've got it to start, but it won't start regularly unless I
bridge the fuel pump relay to get the system pressurized,
then put the relay back in (it then runs for a second and
the relay clicks). At this point it will start and run fine. 

So I'm thinking (my Bentley's haven't arrived yet) there is
some component that tells the fuel pump relay to turn on
when it needs to maintain pressure. I'm kinda clueless at
this point. Help. . .

Thanks,
Dave
87 4KCS quattro
dnevin@kuhub.cc.ukans.edu