Not for a Toyota but general fuel pump question

[Audi]

I'm working on my mates Suzuki Alto and I have discovered to root of the problem, no power to the fuel pump, but no solution. I have rigged up and alternate power source to the pump (just another battery) and it works fine, but it run constantly.

My question is, what usually regulates the running of the fuel pump on mid 90s carbureatted engines? There is a third cable running there, would that be involved? I can't find where the existing cable is flawed so I would just replace it but I need to regulate it. Any ideas?

[rollaholic]

i would have thought the relay would have been your first port of call?