> Tom C <[EMAIL PROTECTED]> wrote:
> Thanks for the info on Techron, Ed. Where do you find this product? Do
> most of the auto parts places carry it?
>
> Got the sender out yesterday and found the wire to the sender had broken
> almost in two. Looks like that was the problem with the gauge....and why
it
> was acting so crazy. Now, something I can't figure out. Nate, you
> mentioned a ground wire. All I saw was one 'double' wire going to the
> sender....like a standard double-wire lamp cord, but smaller. And it
looked
> like BOTH wires were attached to the sender. In other words, the wires
> weren't separated.....with one being a hot wire and one being a ground. I
> don't see any place a ground wire was....or could be....attached. However,
> the wires were broken, and it's hard to tell. Plus, the wires broke off
> completely when I was trying to get the sender out. Big question now
> is....how are the wires supposed to be attached? Is the ground wire
> supposed to be separated and attached somewhere? I'm stuck on this one and
> really need some help!
> Tom Caperton
> '47-2nd Series ... in Whiteville, NC
> [EMAIL PROTECTED]
>
Tom,
All this talk about gas gauges got me working on mine as well. In the 3800's
the tank is up under the bed, between the rails.
The sender and gas pickup tube are all in one. I replaced my tank last year
and re-used my sender, which was good at the time. It of course soon failed
there after.... I drained and dropped the tank yesterday, turns out the
copper float had failed so the sender was always sunk (=empty).
The sender has a center post with screw for positive connection, next to
where the gas line exits, and your positive wire attaches there. Any of the
surrounding flange screws which attach the sender to the tank itself may be
used for the grounding post., or for that matter the tank itself can be the
ground, and that may be in your case since you don't see an obvious ground.
Best would be to ground it at the sender flange though, as the gasket
between it and the tank, or a imperfect ground for the tank itself might
keep the sender from working consistently. Ground it to the chassis
somewhere convenient. If you have a double lamp cord type wire going to the
center, sounds like a replacement repair at some time in the past.
As far as acting "crazy" the resistor in these units is in fact a very fine
piece of wire of a specific impedance and length wrapped around a
strip of plastic, and as the float and arm goes up and down the contact
inside the sender gauge slides over this winding. It is a very simple
mechanism, and can be re-wound. If there is a break in the winding it can
fail and pop to full and then down again as it passes over the break. If you
are so inclined, pop this little gizmo apart and look for breaks in the fine
wire, or gunk. If any debris has settled on the windings that also can break
the continuity causing the dash gauge to pop to full. I've rewound mine a
couple of times, it's tedious, but works fine. You can fix breaks simply by
twisting the wire together, and carefully winding it back on.
The housing for the resistor also should have the resistance (in ohm's)
stamped on it. 30 ohms up until 1955 I think, and then 90 ohms from then on.
A 90 ohm sender in an earlier model will register a bit over half a tank
when in fact the tank is full, and the float is fully elevated. Such is the
case with mine. That all said, I found that AutoZone has a replacement in
inventory. I ordered one today. Will let everyone know if it is junk or not.
Happy New Year to all.
Casey
Ole Chevy and GMC trucks rule!
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