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Fuel Tank Not Venting

Discussion in 'Builds and Fabricators Forum' started by Dphillip, Sep 9, 2018.

  1. Sep 9, 2018
    Dphillip

    Dphillip Member

    Omaha NE
    Joined:
    Nov 25, 2008
    Messages:
    322
    Last week on the trail in Moab I was getting crazy pressure build up in my gas tank to the point it would occasionally blow gas out of the fill cap. It makes no sense because the two vent lines from the tank are unobstructed, the roll over valve is open and unobstructed and the vent line to the charcoal canister is unobstructed. The canister checks out with no obstruction and the ported vacuum line from the throttle body applies vacuum as soon as the throttle plates open. I’m suspecting the 42 year old roll over valve is acting up and I now have a newer replacement on order.

    Am I missing something here?
     
  2. Sep 11, 2018
    Dphillip

    Dphillip Member

    Omaha NE
    Joined:
    Nov 25, 2008
    Messages:
    322
    I removed the 42 year old roll over valve and replaced it with a newer style. I think this valve is from a later model Jeep and normally mounts at the top of the tank. That’s a much better design than having two small vent hoses exiting the side of the tank then routed up to the roll over valve behind the fender. After some test driving yesterday there was no pressure build up the tank but it wasn’t 100 degrees and I wasn’t out on a bumpy trail. Time will tell?




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    Lockman likes this.
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