Sending unit has weird vent thing

Fuel and Air Systems

  1. Richie

    Richie Well-Known Member

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    Hi everybody:

    I didn't pay much attention to it because it was suppose to be the right one but the 3/8 sending unit for my 69 Dart has a weird vent tube going into the main line. Should I just plug it?

    prdp_774.jpg
     
  2. Dana67Dart

    Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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    Fuel vapor return line.

    Do you have your old sender?

    Is it functional, dies it look like your replacement?
     
  3. Richie

    Richie Well-Known Member

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    It's too small. No it's not like this new one it only has the outlet for the gasline..Why not just plug this one?
     
  4. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    It is a return line. It can be plugged as long as you have other vents for the tank.
     
  5. Richie

    Richie Well-Known Member

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    There's the vent on the filler tube. The guy at the shop said "those things are ILLEGAL!!" I never heard of any A-Body blowing up from fumes in the trunk..
     
  6. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    They don't (and better not) end in the trunk. They end below the big rubber boot/ gasket in the rear frame rail.
     
    • Agree Agree x 1
    • Mike69cuda

      Mike69cuda 64 is the new 17 FABO Gold Member

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      I just did the same thing with mine. Just plug it and clamp it.
       
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      • Richie

        Richie Well-Known Member

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        Ok I have a PDF shop manual and I see what you mean by where the vent tube from the filler neck goes
         
      • 67Dart273

        67Dart273 FABO Gold Member FABO Gold Member

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        Mopar never made a two nipple sender. These are aftermarket. If you have a later model (some 70, some 71, and all after) that has evap emissions controls, these cars vary. But all end up with a line from the tank vent system coming into the engine bay and connects to the "carbon can" evap system

        You can just plug the sender fitting. If you ever build an anti-vapor lock system (they work!!!) you can use that fitting for a return.
         
      • Dana67Dart

        Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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        Reason I was asking about your old one. If it is OEM. save yourself a ton of frustration and have it rebuilt. That way your guage will read correctly.
         
      • Cruze426

        Cruze426 FABO Gold Member FABO Gold Member

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        That's right, and they can make it 3/8 if it was 5 1/6. That new stuff is junk.
         
      • Richie

        Richie Well-Known Member

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        I thought they were just a chuck away item?
         
      • cryplydog

        cryplydog Member

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        Guys, where do you send them to get rebuilt with 3/8 tube?
         
      • Richie

        Richie Well-Known Member

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        Good question
         
      • rumblefish360

        rumblefish360 So close, yet so far away FABO Gold Member

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        Use a solder gun on your hand bent tube that mimics the stock one that gets cut off and drilled out.
         
      • Cruze426

        Cruze426 FABO Gold Member FABO Gold Member

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        Call Tom at Instrument Specialties, he reconditioned my sending unit. He should be able to do it. A friend of mine swapped out the 5 1/6" to 3/8". Like post #15 said, unsolder the 5 1/6 tube, bend up a new 3/8 tube with tubing bender and solder or tig weld it back in. Get a new 3/8 end filter.
        There are other people that recondition these sending units, maybe someone else can jump in with their names.
         
        Last edited: Jul 28, 2020
      • kursplat

        kursplat FABO Gold Member FABO Gold Member

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        ...duffus
         
      • Richie

        Richie Well-Known Member

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        Well I see his point now..I'm the idiot in this one because I thought it was perfectly fine to have the filler tube vent end in the trunk of the car. That's what he was commenting on.
         
      • kursplat

        kursplat FABO Gold Member FABO Gold Member

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        gotcha, i took it as having the vent off the filler it's self he had an issue with
         
      • Richie

        Richie Well-Known Member

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        Nope ...I'm the bone-head in this battle :lol:
         
      • Dana67Dart

        Dana67Dart Like a fine wine, only getting better with age! FABO Gold Member

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        If you still have your OEM sender and don't plan to have it referbushed, I might be interested in buying it.
         
      • moparmarks

        moparmarks FABO Gold Member FABO Gold Member

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        Actually 440hp and Hemi cars had a 2 nipple s/unit. 3/8" supply and 1/4" return. They had a vapor separator canister by the fuel pump where the 1/4" return lines starts and ends up at the 1/4" on the sending unit.
         
      • Richie

        Richie Well-Known Member

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        Found this pic in the shop manual. Looks like there is a small hole in the rubber trunk seal and the vent goes above the tank

        50164785952_d20ef207fe_b.jpg
         
      • Cruze426

        Cruze426 FABO Gold Member FABO Gold Member

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        Was just going to detail this and realize, do you have the vent line?
         
      • Richie

        Richie Well-Known Member

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        Just on the filler tube
         
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