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Can someone give me the nominal resistance range of the rheostat in the sender. I'm building a circuit to test fuel gages. Thanks
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0 ohms empty, 90 ohms full *NM*
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Re: Fuel Tank sender
Radio Shack has a 0-100 ohm variable potentiometer (a/k/a volume control) for five bucks that makes a great diagnostic substitute for a fuel gauge sending unit; if they don't have one hanging on the wall, they can order it from the catalog. Also works great for determining additional resistance required to make a temp gauge read correctly, although the gauge will no longer be linear across its range with "calibration" resistance added.Comment
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Re: 0 ohms empty, 90 ohms full
OK I give up, how do you measure the resistance on the fuel gage sender? I know it should be 0 to 90 ohm but does it have to be measured with a John Fluke meter that I do not have? My 24 gallon tank has never worked right so I peened the bad connection (resistance read zero almost all the time) on the wire connection on the sender. I measured mine with a standard (cheep) meter and could barely see any change from one end to the other, like 1 ohm to about 3 ohms but the gage started working, holding the sender in my hand with the sender hooked up to the gage. The gage read about 1/8 tank on the bottom and barely above full with the float at the full position. Any help is appreciated.
Gene
fuelie1962@aol.comComment
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Re: 0 ohms empty, 90 ohms full
Gene,
I may have missed it in a related post, but I don’t know if you are talking about a C 2 or a C3. If it is a C2 then I may be able to help you. First off, you should be able to do a rough measurement with your “cheep” meter. (It should definitely be able to tell the difference between 1 ohm and 90 ohms, as long as you have it on a low enough scale.) When you do this measurement, you should be measuring at the sender unit with all of the wires disconnected (i.e., you don’t want the gauge in the circuit).
When you stated “the gage started working, holding the sender in my hand with the sender hooked up to the gage”, this could be because that while in the gas tank, the wiper arm of the 90 ohm potentiometer may not be making a really good contact. But, when you hold it in your hand, you move it enough to make it work. You could fix this by removing the cover to the potentiometer and you will see the wiper arm and the wire-wound resistance wire. If you do this, be very careful. This internal part of the sender is very delicate. You can’t just bend the wiper arm and hope that it works. It may not be touching the wire-wound resistance wire because the cover is loose. It is only connected by a few tabs (if it is the original style sender).
Another reason for it not working could be because one of the tabs on the sender is making a bad connection either at the wire side or internally.
GaryComment
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