I'm beginning the process of shaving the gas door on my Buick. I dropped the tank and have a question about the vent line. You can see in the picture that the vent runs from the filler neck back into the tank. Is this type of setup okay for when I move the filler neck into the trunk? Posted using the Full Custom H.A.M.B. App!
If you do that and use a vented gas cap, then all of your fumes will vent into your trunk. I would run that little vent hose outside of the car somehow, and get a non-vented cap to have inside the trunk. Just make sure the vent hose has a potion where its higher than the tank, so that your gas doesnt leak out when you have a full tank (ask me how I know this )
the stock cAP is not vented the vent line just runs from the filler neck back into the tank. I am planning on doing the same exact setup. Sounds like a long as its not venting into the open air I'm good. Thanks! Posted using the Full Custom H.A.M.B. App!
Remember your tank has to be vented somewhere when the gas cap is on. As your pump drains the tank, air needs to get in to replace the space the gas was taking up. ***uming there's no other vent, pull that small rubber line and seal up the flared end by the the gas cap. Hook up a new length of hose (longer the better) to the tank end and run it outside to your wheelwell or something. To stop gas spilling out when you go around corners loop it up and down at a point that's higher than the tank, if you want to be extra safe put a simple safety valve in it (you can steal one out of any late model or find them at marine places).
There's usually a dual purpose vent. The 3/4 line in the pic is a fill vent, as the fuel goes in the air in the tank needs to come out. If the air can't get out, you'll splash fuel out of the fill neck. The latest style gas pumps have that silicone boot that fits over the fill neck to catch this displaced air. This is why it runs full length to above the end of the fuel nozzle dispersing the fuel from the station pump. The next vent, usually in the cap is to prevent a vacuum in the tank by letting air in as the fuel is delivered to the engine and slowly comes out. Most of these are a one way vent, meaning they will hold pressure but vent on vacuum. The next vent would be a evap related system to capture and later reuse the fuel vapors. There's ways around all of those. First one would be to fill the tank very slowly and watch that its not creating an air lock. Second one is to use a sealed cap but install a small vent port in the fill neck. From this port run a rubber hose in such a fashion that it goes higher than the tank and on the end of it install a fuel filter. The fuel filter will keep dirt out of it as its venting. The end needs to go to atmosphere and be hidden. Into a wheel well usually works well. Be sure this work around has roll over protection. You could even run this into a charcoal canister if you wanted. The third is usually taken care of by the previous.
Use a non-vented cap and run a vent line (brakeline) out the filler neck, through the floor... (photo from tugmaster)
That's basically the set up from the factory. I guess to be safe I will split the vent line that goes from the filler neck back into the tank and run another line into the wheel well.
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