fuel tank venting clarification

Discussion in 'Troubleshooting & Diagnosis' started by biggrass, Jun 1, 2017.

  1. Printstron

    Printstron Veteran Member Lifetime Gold Member

    Mar 16, 2010
    Bakersfield, California
    Yeah, I've seen this before and it looks awesome. But that price though!!! To save that amount I'd just go ahead and put my charcoal canister back in and run a vac line.

    I've seen a few other forums and they are all just like this one. No clear answer. It worked for one guy and then not the next.
  2. bourbon_scotch

    bourbon_scotch Veteran Member Lifetime Gold Member

    Jan 10, 2003
    What if you just ditch the charcoal canister and run the vent to the air intake somewhere. That way the gas tank would get air if it needed it and if it needed to vent vapor it would just go into the intake.
  3. Printstron

    Printstron Veteran Member Lifetime Gold Member

    Mar 16, 2010
    Bakersfield, California
    My main reason was engine bay de-cluter. But thats not worth it if I have to sacrifice breathing in the garage. If a hose needs to be run to the front I might as well do the whole thing canister and all. Still going to give the vented cap a shot first though.
  4. cnlmustard

    cnlmustard New Member

    Nov 2, 2000
    New Orleans, LA, USA
    So, does anyone know whether the 79 came with 2 tank vent connectors, or just one?
    Carbon canister gone long ago. I have a metered tap I installed on my carbie inlet, to allow a small trickle back to the tank. It keeps the whole tank supply line run cool while running. Works great, allows a few psi to build up in tank and help with fuel pressure feed. The stock caps available will relieve on slight vacuum, but allow the tank pressure to hit 12psi or so before relieving by spring safety.
    For years I wondered why sometimes I smelled gas around the car, and realized the tank was pressuring during weather changes and overpowering the float valve. My carbie has been runneth over, onto and into the manifold! That's not good at all.
    So I drilled out the valve in the cap, and that issue stopped, but now don't get enough fuel pressure (down to 2psi) near WOT and the car stalls.
    My Carter high volume pump may just be getting too old? Is there an old screen in the tank perhaps?
    I put a new non vented cap back on and it runs fine again, but same issue with overpressure again.
    Too bad they dont have a cap with 2psi relief.

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