# fuel level sender ohm readings?



## virginiavenom (Feb 20, 2011)

I'm in a bit of a predicament trying to get my autometer fuel gauge to work properly. I believe the problem exists because it was not designed for use on a tank which actually grounds the sensor. 

my ohm meter reads .2 ohms from the sender unit to the chassis ground nearby. obviously this kills any use of this sending unit. does anyone know what the factory fuel level sender ohm levels are? currently I'm without a fuel gauge other than the pretty lights :cool


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## Rukee (Feb 8, 2007)

Most all fuel sending units work on the ground side. Test the gauge itself, you should be able to get a change in the gauge by disconnecting the tank wire (take a reading) and then with the sending unit wire grounded. Be sure the key is on. If you can't get a change in the gauge, then I would say it's wired wrong or it's a bad gauge. Or maybe check their website for some insight.


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## virginiavenom (Feb 20, 2011)

well autometers gauge is 30 ohms full to 240 ohms empty. I'm a pretty decent electrician. the part that is installed is rated exactly as that, however when I put an ohm meter between chassis ground and the actual sender lug on both the gauge with wire connected and the sender lug on the sending unit they both read .3 ohms (closed circuit) this is even with the wire disconnected at the sending unit itself so there is no chance that the wire is grounding itself out some how. my only guess is either a faulty unit, or it isn't designed for use in a metal tank (no mention of this anywhere and I can't think of many tanks that aren't metal themselves and grounded on vehicles short of small engine stuff.


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## Rukee (Feb 8, 2007)

Test the gauge, not the sending unit. You should be able to see a change in the gauge from an open circuit(dissconnected wire) to a closed one (grounded on frame). Hooking the gauge wire to a test light to ground should put you somewere in the middle. There should be a ground wire between the sending unit and a body ground too.


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## 68greengoat (Sep 15, 2005)

Disconnect the wire going to the sending unit and ground it out. If the gauge pegs full, both the gauge and wire are fine...... At least that's how it worked on my boat.


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## Pontiacdude (May 4, 2011)

I believe you asked what the factory ohm for the fuel guage is. I believe it is 0 to 90 ohm.


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## crustysack (Oct 5, 2008)

I have an autometer fuel gauge (phantom series) installed in my 65 . I am running a stock style sending unit and it works fine- make sure you connect the gauge ground to the same point as the tank ground. Also sender resistance is 90 full and 0 empty. And one more little tidbit make sure the sender is not installed sideways- it wont work correctly that way either( ask me how I know)


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## virginiavenom (Feb 20, 2011)

lol, it's mounted from the top, the ohm reading for the gauge and sender are matched, however I believe I have received a faulty fuel level sender from autometer. if factory is that ohm rating the gauge would be very off. gauge works fine.


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## virginiavenom (Feb 20, 2011)

ahhhh, fixed it! pulled the sender out only to find that the wire that goes down into the tank and coils around was just barely pinched by the top and was grounding out. all is good now.  Thanks guys.


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## likethat (Oct 5, 2007)

crustysack said:


> I have an autometer fuel gauge (phantom series) installed in my 65 . I am running a stock style sending unit and it works fine- make sure you connect the gauge ground to the same point as the tank ground. Also sender resistance is 90 full and 0 empty. And one more little tidbit make sure the sender is not installed sideways- it wont work correctly that way either( ask me how I know)


Some times we play jokes on ourselves and don't even know it.


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