Okay, so i replaced the gearbox, and whilest doing this i put a bit of stress on the vac pipes (but hard to tell). So it's all back together, half a tank of fuel so i know it isn't that. It cranks fine, and now and then on first crank it goes to start but doesn't. pointing me towards fuel,so i had a look at the fuel input pipe wite vac pump and fuel came out, so i checked the clear pipe...which is empty for some reason. When i use the vac pump it sucks fuel through. I've read that an air leak would cause the fuel just to return? Can anyone shed a few lights of what this could be. oh the car started first click before we changed this, so i know it's not relays, or pumps etc, please also don't say go to an audi garage, as that seems to be a few folks fixes here.