I returned mine to the filler neck with my AD150 at first but then when I put the sump in, I pulled the filler neck T fitting out, replaced the filler neck hose, and ended up modifying my setup to use the 1/2in draw straw that also came with the kit as the air return port. I don't know if you have this or not but I would do what Chris said with using the OEM draw straw if you're using a sump. I would just pull the whole sending unit/draw straw/return line out and cut the factory draw straw near the top and stick it back in. JMO of course. Hope it helps.