78 Camaro. Using evap line to charcoal canister as fuel return?

Discussion in 'Troubleshooting & Diagnosis' started by Tom715, Jul 6, 2019.

Can you safely use the eevap line as a fuel return?

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  1. Tom715

    Tom715 Member

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    I was experiencing vapor lock. And yes, I also plan to get a plastic spacer for the carb. What I did was install a vapor seperating filter at the highest point in the fuel line, and plumb the nipple with the orifice in it to the metal evap line comming from the tank on the line on the drivers side that used to go to the charcoal canister. Used new rubber line, left old stock metal line. I installed a shut of switch for safety "just in case" and also so I can partially shut it if I see a drop in fuel pressure. It's main purpose if to eliminate vapor but yes, fuel does pump through like a return line. Just at a lower volume/pressure than the main line. Here's the thing... I have heard multiple opinions of it being both a great idea and a bad idea. I understand that it can build pressure in the tank, and thus I should get a vented cap. I want to hear your opinions.... 0705192052a.jpg 0705192052a.jpg
     
  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Short answer - no. That line is intended for vapor only and has a very small restrictor inline. Try working something like weed eater line through it, you'll find out. Check your fuel line(s) where they come into the pump, some models like my 79 Z28 have a separate 5/16" fuel return line.
     
  3. Tom715

    Tom715 Member

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    Yet, it's working. It may have been intended for vapor only, but its functioning for another use. Is there anything that would cause detriment or danger by doing this? The vapor seperating fuel filter also has a very small restrictor (orifice). I'm not trying to argure trust me, I'm just trying to get to the bottom of this debate once and for all. Half people say use it, half say do not.
     
    Last edited: Jul 6, 2019
  4. badazz81z28

    badazz81z28 Veteran Member

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    It’s a steel tube...unless there is something blocking the path, it should work fine.
     
  5. Zspoiler

    Zspoiler Veteran Member

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    Your vapor ist to help prevent vapor lock by relieving the pressure in the tank.And it also increase fuel mileage > I would use a thick carb gasket and an aluminum heat shield to take care of your vapor lock.
     
  6. dale68z

    dale68z Veteran Member

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    I am using the same thing my edelbrock carbed 350 on my 72 el camino. Have had it on for about 3-4 years and 20k miles. No issues.
    Keeping fuel moving is a big deal when sitting in traffic. Low fuel volume without a return allowed the fuel to get too hot and boil.
    it also helped significantly when restarting after a hot soak.
    I do not have a vented cap, and should, but have had no issues.
     
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  7. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    I use the factory lines for fuel feed, venting and fuel return.
     

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