Tomorrow I need to fit an elecric fuel pump and hopefully get my astra(mk2) running again. I have looked under the car and there are two lines comming from the fuel tank. The engine is a 1.8 gte but I have fitted a carb to it. I dont know which line to fit the fuel pump in and what to do with the other line. The car use to be a 1.6 carb so the other line is not the return that you would have on an injection car.
Most carb engines also have a return line (to keep a supply of cold fuel to the carb).
The easiest way to tell which is which would be to look at the bore size of the pipe. the larger bore pipe is the feed, smaller the return. If you don't need the return pipe just blocking it at the engine end should be fine (just make sure it's tied out of the way)
Don't know if astra's are the same, but injection nova's have a 'swill pot' in the tank to keep a constant feed of fuel to the pump. If you use a standard carb tank you can end up killing the pump due to air getting pumped round. I guess you have a low pressure pump for the carb, i dont know if it applies, i guess not.
Don't forget a fuel filter too, if there isn't one in the carb.
i presume these are metal lines down the drivers side sill ?
If they are they will be the same size, bigger bore for the feed would just loose the pressure from the pump, or require more.
My carb 1.6 never had a return line, theres no need cause theres bugger all pressure and the float in the carb takes care of unwanted fuel by stopping the flow. I'm a little confused why you have two lines, if your sure its not brake lines or something there should be a join just below the bulkhead where the metal hoses go to rubber for the engine bay, same the tank end. Just remove the rubber the engine end and bung the tank end, leave a little coming from the tank and wind in a massive long thin bolt or something.
you can get a thing from 2 litre sierras that is a pressure regulator for carbs. you should be able to an electric pump to feed the regulator and the regulator has a return back to the tank and a feed for the carb. that will stop vapour locking by keeping a cold supply of fuel
check all your fuel lines cos theyll be filled with crap if the cars no run 4 a while , and watch out for perished or rusty pipes.