Fuel pump connections, polarity?

Hello all,
I recently purchased my MK1 1.6 Gti which has a few problems with it, hopefully I am going to fix them and get a nice little car out of it.

The first thing I am doing is replacing the fuel pump. I have a pump from another Mk1 but there are no polarity markings on it. I does however have one larger terminal than the other. I would normally think this means ground but just want some re-assurance from someone.
Does anyone know the answer to this?
I have checked the old pump, but the terminals are both the same size on it.
If I get the connections the wrong way round will this run the motor in reverse or damage it?

Cheers,
Rich

the live will more than likely be yellow/red and the earth brown go check your wires  :wink:

I know the polarity of the wires. I'm talking about the terminals on the fuel pump.

has it not got the + and - marks by the terminals?

they normaly have it marked on them i would imagine if you get wires round the wrong way the pump will run in reverse dont quote me on it tho

whats the new pump out off

Fuel pump terminals should have the polarity marked on it. It would be simple enough to measure the voltage there with a multimeter??

no there are no markings, or at least I can't see them because of corrosion, I have tried scraping it back but can't see any.
As far as I know it was off another Mk1 gti, but I was given it by the guy who sold the car. The one on the car has a plastic surround where the terminals are and has clear markings, whereas the new one is metal at the top.

to be honest i think you may be better of buying a new pump from gsf cos even if you get the pump you have wired up it may not last 5 minutes

I thought you might say that. I was thinking of sticking this one in, if it fixes the problem at least I know its the fuel pump and maybe get a new one. If it doesn't fix the problem I have wasted some money on a new fuel pump.

I'll go have a play see what happens.
Thanks for trying,
Rich