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Fuel Tank Pressure and Gas Smell

Discussion in 'Engine and Drivetrain/Mechanical' started by JonnybravoM3, May 27, 2018.

  1. JonnybravoM3

    JonnybravoM3 Member

    I have a question about our fuel tanks.

    Now I've always had a problem with my 65 mustang stinking up my garage with raw fuel smell, I've ticked every single box and still have this issue.

    I've changed the fuel filler hose and clamps and gaskets, I've checked all the lines, replaced the rubber with braided fuel lines, no leaks, I have a brand new Tanks, Inc fuel tank with an in-tank pump and vent valve installed in my upper wheel well.

    I bought a pressure release valve thanks to the advice of some members (attached) and installed it in the place of the roll over vent valve, and this did improve the smell only very very slightly, plus I got worried about excess pressure build up in my tank, as the pressure release valve only releases excess pressure up to a point but remains closed otherwise and keeps your tank constantly under pressure (I worry about that being a ticking time bomb perhaps?)

    Perhaps my biggest "curse" is that I have a fully closed airconditioned garage, had it only been open, I probably wouldn't have this smelling issue. I could leave the back door open, but with our 120F summers and dust etc outside, I would prefer not to!

    Any advice would be highly highly appreciated! Also, is there a risk in using the pressure release valve that I posted? My mechanic recommended against keeping the tank under constant pressure like this.


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  2. Horseplay

    Horseplay I Don't Care. Do you?

    The valve is specifically designed to be used in a closed fuel system to protect against an over-pressurized condition. It is fine to use. It takes less than 1 p.s.i. of pressure to open the valve.

    https://www.newton-equipment.com/In-Line Tank Vent Valves TPV Series master.pdf

    As far as gas "fumes" go even though you are using the FiTech system it still works in a way like a carburetor in the manner in which the fuel is dumped into the intake plenum as opposed to a direct port type modern fuel injection system. Seems logical to me that the residual gas smell will be present. Also, unless you used teflon lined braided fuel hoses all you have installed in place of the rubber hoses are rubber hoses covered in braid. I have read many complaints about plain rubber braided lines smelling even worse of gas fumes.
    JonnybravoM3 likes this.
  3. JonnybravoM3

    JonnybravoM3 Member

    You've always been most helpful thank you. Is there no risk to this built up pressure in one's tank?

    Even in the heat?

    Sent from my HTC U11 using Tapatalk
  4. Horseplay

    Horseplay I Don't Care. Do you?

    Pressure is pressure. Hot or cold the valve is designed to open and close at set levels. Yes, the hotter it gets more pressure can be created in the tank but the valve is designed to remain open and vent it to the predetermined level so no damage can be done or dangerous situation created. You can certainly just revert back to the 60's method of pressure control which is to simply leave an unregulated vent to the atmosphere but that will certainly result in tank/gas fumes being exhausted more so than the valve set-up. In your case, with a temperature controlled garage, the valve provides the opportunity to keep the system sealed closed when parked inside.

    The tank is welded steel. Both the metal and the welds can withstand the small amount of pressure that may reside in the tank. Hell, a fuel line would rupture long before the tank. But relax, fuel line is rated to at least 50 p.s.i. itself. Braided even higher, obviously. You are way over thinking this one.
    JonnybravoM3 likes this.

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