Does anyone know how a fuel pump is controlled? Or is it always on full blast, no matter how much gas you give it?

I'll probably need another fuel pump before I go FI, and I'd like to understand this before I slap one in from another car and start splicing wires.

 

Honda fuel pumps get alternator voltage whenever the car is running. When the switch is first turned to the on position, the pump primes for 5 seconds(accompanied by the MIL), and then stops, but is always on when the engine is running.