What kind of car? Carburetor or fuel injection?

Good luck.....some fuel injected cars can be a bitch to prime if you
run thm out of fuel.

What I used to do when I replaced in the tank fuel pumps was to use an
air compressor to pressurize the fuel tank with about 20 psi.

I would always replace the fuel filters and under the hood at the fuel
rail of the throttle body injector I would disconnect the line.  Then I
would have a helper watch for fuel as I gently pressurized the tank.

Yah see most electronic fuel pumps have a shut off so that if pressure
is not reached within a few seconds the pump shuts off.   This is to
prevent fires in the event of plumbing problems under the hood.

If you want to find the "switch" go to an auto parts place and but the
propper manual.

you probably sucked the filter sock flat or seized the pump, tow it to
a shop or dealer, no reason to run a vehicle below 1/4 tank.

so you posted a question about a Saturn to a Studebaker newsgroup.

Welllllll.... that actually makes sense :)

Often on a modern FI car when you turn the key on the fuel pump will
run for only a few seconds to "prime" the system and then shut off and
not run again until it gets a signal that the engine is running (from
the ignition, crank position sensor, cam sensor, something like that.
It varies with the car but the principle is the same.)

What that means is, if your tank is now full, or at least has enough
fuel in it, you may be able to get the system to prime simply by
turning the key on (but not trying to start the engine) wait 10 sec. or
so, turn it off again, turn back on, wait 10 sec., etc. repeat maybe
10x and then try to start the car.  It might work, and save you a tow
bill...

You should be able to actually hear the fuel pump run when you turn the
ignition key on and then stop running after a few seconds.  If you
don't hear it at all you may have a fuel pump issue, but I suspect that
you've just lost prime.

good luck,

nate