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Jumping gas guage fix?

Discussion in 'The Hokey Ass Message Board' started by t-town-track-t, Sep 23, 2010.

  1. t-town-track-t
    Joined: Jan 11, 2006
    Posts: 884

    t-town-track-t
    Member
    from Tulsa

    When I bought my '54, it had been sitting for a while. One of the first things I did was to replace the gas tank. I bought one of those fancy new poly tanks, and a new sending unit. I figured it was the greatest thing since sliced bread, and that I would never have to deal with a rusty tank ever again.

    Well, I still think that. However, the one thing that I hate about this tank, is that it is not baffled. So when I hit the go pedal, the gauge drops rapidly, and when I stop, it rises. Sitting at a stop light, it bobbles around. I know alot of the late model cars have something in their circuitry that slows down how quickly the gauges react to changes in fuel level.

    how do I accomplish this in my vehicle? Is it something that I can build myself with parts from radioshack? Surely I am not the first person to have to deal with this...
     
  2. Merlin
    Joined: Apr 9, 2005
    Posts: 2,546

    Merlin
    Member
    from Inman, SC

    I have the same thing in my 32 so I'm curious about what can be done if anything.
     
  3. marks914
    Joined: Feb 20, 2009
    Posts: 330

    marks914
    Alliance Vendor

    The problem is that the oil that dampens the movement is long gone. That and a tank that sloshes around a bit will cause the pointer to jump all over!
    Mark
     
    Last edited: Sep 24, 2010
  4. Deuces
    Joined: Nov 3, 2009
    Posts: 18,785

    Deuces
    Member
    from Michigan

    I'll probably have rocks thrown at me for this... Use an Auto-Meter oil filled gage... :D
     
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  5. Muttley
    Joined: Nov 30, 2003
    Posts: 18,420

    Muttley
    Member

    The Stewart Warner I put in my Comet does the same thing.
     
  6. badgeree
    Joined: Feb 6, 2009
    Posts: 339

    badgeree
    Member

    No jumping around with my fuel gauge, the needle doesn't move from 3/4 full. It's ALWAYS on 3/4 full. ........ Should get around to fixing that.:rolleyes:
     
  7. oldcarkook
    Joined: Nov 4, 2007
    Posts: 58

    oldcarkook
    Member
    from Bahstin

    You can baffle the tank after the fact using "Baffle Balls" or whiffle balls. We use Baffle Balls in poly chemical tanks in my business and they are 15" diameter and designed to drop into tanks with 16" manways, but you could likely get small whiffle balls through the sender unit opening and accomplish the same thing. Some of the rock crawlers use whiffle balls to baffle their fuel cells.
    [​IMG][​IMG]
     
  8. Muttley
    Joined: Nov 30, 2003
    Posts: 18,420

    Muttley
    Member

    You must have to jam an awful lot of those in the tank to have any affect. How much does that cut down on the tank fuel capacity? It also seems like they would interfere with the sending units normal operation. :confused: :confused:
     
  9. onemintcaddy
    Joined: Feb 7, 2007
    Posts: 376

    onemintcaddy
    Member

    On my 69 Impala convert there was a can stile pickup with the sending unit inside, Never seen one like it before this,,, What a "Bitch" to rebuild.
    Come to find out that with out the can my gage would jumped all over the place with the new replacement unit. Works good now,,,, So far..
     
  10. Dirk35
    Joined: Mar 8, 2001
    Posts: 2,024

    Dirk35
    Member

    I would also think they would interfere with the movement of the sender.

    But, real reason Im actually posting on here is to ask, how would you determine that the whiffle balls are made from a type of polymer plastic that the gas would not dissolve?

     
  11. atomickustom
    Joined: Aug 30, 2005
    Posts: 3,296

    atomickustom
    Member

    That is a terrible idea! The gas gauge sending unit on his Chevy works because a float raises an arm up and down - as soon as you add an object to the tank you are begging for the sending unit and the wiffle ball to get together and render the gas gauge useless.

    I have a poly tank in my '53 and the gauge does not jump around. Did you use your original sending unit? If so, pull it out and carefully clean the rust and crud off of the little wires wound around the shaft. Anything on there will interfere with the signal. (I know this because MY gauge was jumping around a lot after I changed my tank. Cleaning the residual crud off of the sending unit or replacing the sending unit should fix it.)
     
  12. t-town-track-t
    Joined: Jan 11, 2006
    Posts: 884

    t-town-track-t
    Member
    from Tulsa

    Its a brand new sending unit as well.
     
  13. t-town-track-t
    Joined: Jan 11, 2006
    Posts: 884

    t-town-track-t
    Member
    from Tulsa

    And I am running a stock dash, so changing it out for an aftermarket fuel gauge is not much of an option.
     
  14. atomickustom
    Joined: Aug 30, 2005
    Posts: 3,296

    atomickustom
    Member

    Huh. Do you have a good connection from the sending unit to a ground? I can't think of anything else that would cause that problem.
     
  15. Special Ed
    Joined: Nov 1, 2007
    Posts: 6,003

    Special Ed
    Member

    We had a similar situation on a client's '53 Chevy....We ultimately installed what I would describe as a sending unit inside of a 2" cylinder. The cylinder would keep the sender very stable, and keep it from bobbing around as gas sloshed in the tank. It was the only car I ever had to do that with, but somebody makes that whole unit just for what you described....
     
  16. KrisKustomPaint
    Joined: Apr 20, 2007
    Posts: 1,107

    KrisKustomPaint
    Member

    http://www.freepatentsonline.com/4838082.pdf
    here is a circuit i came across to do that, but you would have to find some one to give you some ball park figures on what resistors and diodes and what not to use. It was assigned to chrysler in 89 so maybe they used some thing similar that you could bogart out of a car.

    some older guages used bimetalic strips to buffer the signal. the AC guages had two coils clocked at 90 deg.

    Checked my old motors manual, and the buffer on the AC guages is "a calibrated friction brake included in the tank ..." so I'm guessing some sort of friction device mounted to the sender which is why your new sending unit makes the gauge erratic.
     
    Last edited: Sep 27, 2010

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