Orignal sending units are zero - 180 ohm units. They are actually
only reasonable approximations of those numbers but clearly the
sending unit you're talking about using is wrong for the job on a
couple of counts. Remember, the original unit reads empty when the
reserve amount is still in the tank (assuming you're using an
original fuel shut off) and I think that is a handy feature. Unless
you're throwing out the Amphicar gauges there's no way I'd fool
around with an incorrect sending unit. If you are changing the
gauges, all bets are off.
John Friese
67 White
67 Red
--- In amphicar-lovers@yahoogroups.com, rogtwo@a... wrote:
> I bought a TEMPO fuel level sender a couple of months ago. Ed's
data gave me
> the push I needed to see if it would work in my Amphi. The TEMPO
sensor I
> got is labeled on the package as Part No. 280050 (Model No.
570ESU). * This
> unit, like the Stewart-Warner and Auto-Meter models, is 240 ohms
empty and 30-35
> ohms full. This is obviously not good because it has the high
resistance in
> the empty position instead of the full position.
>
>
http://www.tempoproducts.com/2004/gauges.html
>
> But wait! The stainless steel wire that the float is on can be
bent to
> reverse this. If you want to use one of these gauges, follow the 3
simple steps
> below.
>
> NOTE: The only issue with this conversion is that the fuel gauge
will not go
> quite all the way to empty. When the tank is empty, my needle goes
down to
> where it is about one needle width above the empty mark. If you
can't remember
> this when driving, then you better get a different sender.
>
> Here are the steps to modify the TEMPO sender (I think this sender
costs
> about $25):
>
> 1. Grab the stainless steel float wire about 1 inch from its pivot
point with
> two pairs of pliers. Bend the wire through 125 degrees so the
float is on
> the other side of its pivot point. Note, bending the wire through
125 degree
> will leave the wire with a 55 degree bend in it (i.e., 55 plus 125
= 180 or a
> straight wire). Now as needed, when the float is high the
resistance is high,
> and when the float is low, the resistance is low.
>
> 2. Slide the float and its retaining washers up the wire 1.5 inches
and then
> trim 1.5 inches off the end of the wire. Don't slide the retaining
washers up
> further than where you want them because it is difficult to get
them to move
> back the other way.
>
> 3. The 5 mounting holes are not evenly spaced. Thus, the sending
unit top
> can only be oriented one way on the tank. As my unit was
assembled, I could
> not install the sender in the tank because the float would hit the
front of the
> tank. But, it's easy to fix. Unscrew the nut that is on the stud
on the top
> of the sending unit. Separate the 5 holed plate from the rest of
the unit.
> Turn the 5 holed plate 90 degrees counterclockwise and reinstall
it. This will
> make the float point over toward the filler neck when the sender is
> installed. Note, the hole at the center of the 5 hole plate (its
6th hole) is square
> and matches a square plastic part on the stud. Thus, you can only
rotate the
> plate in 90 degree increments.
>
> This should give you a unit that reads full correctly, and goes
almost to
> empty when the tank is empty. Before installing the sender, you
might want hold
> the sender at the end of the tank and verify that the wire is bent
correctly.
> With the 5 hole plate of the sender held level at the top of the
tank, the
> float should not hang below the bottom of the tank. If you have an
ohm meter,
> you can also check that when you swing the float up level with the
top of the
> tank, that the sender has a resistance of about 180 ohms.
>
> * There Part No 280070 gage might be even easier to modify. You
might be
> able to just flip the little black resistor unit of this one up-
side-down.
>
> Roger
> White '63
> Seattle
>
> PS - I can e-mail before and after pictures of the sender if
someone wants.
>
>
> In a message dated 10/8/2004 6:06:45 AM Pacific Standard Time,
wb6wsn@c...
> writes:
> A short time ago, we had a thread on replacement fuel senders. Here
is some
> information that I dug out about various fuel tank sensors.
>
> GMC, 1964 or earlier, 0 Ohms empty to 30 Ohms full
> GMC, 1966 and later, 0 to 2 Ohms empty to 91 to 93 Ohms full
> Ford, 1987 & later, 16 Ohms empty to158 Ohms full
> Ford, pre-1987, 73 Ohms empty to 10 Ohms full
> AMC, 73 Ohms empty to 10 Ohms full
> Toyota, 1985 & later, 90 Ohms empty to 0 Ohms full
> Nissan, 1985 & later, 90 Ohms empty to 0 Ohms full
> Stewart-Warner, 244 to 250 Ohms empty to 29 to 33 Ohms full
> Auto-Meter, 240 Ohms empty to 33 Ohms full
> Amphicar, 10 Ohms empty to 180 Ohms full
>
> This isn't exactly everything that's available; it just shows you
that there
> isn't any "universal" fuel tank sender unit. If you replace the
Amphi with
> "something else", you can get weird results. You have to remember
to match
> the sender's resistance curve to the gauge's response curve.
>
>
> Ed
> El Cajon, CA USA
> 67 Rust Guppy
>
>
> [Non-text portions of this message have been removed]
