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Fuel pump

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by 69K5, Jun 29, 2002.

  1. 69K5

    69K5 1/2 ton status

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    I put my 350 in and the fuel pump has a return line(?). i just capped it off. was that a good or a bad idea? i havent driven it yet. I still have to adjust my valves. I really hate doing that. thanks for the help.

    nathan
     
  2. 69K5

    69K5 1/2 ton status

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    capped it off and she works. i guess its ok

    nathan
     
  3. BurbinOR

    BurbinOR 3/4 ton status

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    Might cause you vapor lock down the road............did me when I blocked my return line off in my Camaro. Fixed it when I put the return line hookup in.........
     
  4. Scorpion

    Scorpion Registered Member

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    As I understand, having a return line takes some of the stress off of the fuel pump when the carb doesn't need as much fuel as the pump wants to send it. I don't really know if it will shorten the pump's life though.

    Matt
     
  5. 69K5

    69K5 1/2 ton status

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    where is the return line supposed to be connected to the carb at? thankjs

    nathan
     
  6. Burt4x4

    Burt4x4 3/4 ton status

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    I was researching this topic and the Early truck motors did not have a return line off the fuel pump. I would get a fuel pump with out the return line and call it good.
    .02c
     
  7. 70~K5

    70~K5 1/2 ton status

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    If you want to use that pump then you need to plumb a line to go back to the tank. It's called a return line cause it returns what the carb doesn't use back to the tank. /forums/images/icons/ooo.gif /forums/images/icons/ooo.gif /forums/images/icons/ooo.gif
     
  8. Steve_Chin

    Steve_Chin 1/2 ton status

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    It shouldn't shorten the life of the pump to have the return nipple capped. The pump contains a few springs, a diaphragm, and a set of poppet valves. If the carburetor doesn't need any more fuel during the pressure stroke of the pump, the spring that provides the pressure stroke simply stays compressed.

    The problem with some cars is that their engine compartments are rather tight, causing fuel heating problems. The return line helps prevent vapor lock by allowing fuel to continuously flow while the engine is running, keeping the fuel cool (preventing fuel percolation in the lines). We don't really have this problem in our Blazers.

    I will say one thing for the return-type systems - if plumbed correctly, a system with a bypass regulator and return line will provide much more consistent fuel pressure than a system without a return line (with a dead-head regulator).
     
  9. 69K5

    69K5 1/2 ton status

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    thank you again Dr. steve. i will leave it capped unless another problem arises. i never was much of a plumber.

    thanksd again

    nathan
     

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