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Discussion Starter #1
The two wires off of the sending unit[black being ground and the yellow going to the gauge correct]. Some how with the power on the float when moved there seems no indication on the gauge is moving to show its made up. I have a good ground, and the right ohm sending unit what im I missing here.
 

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Greg the first thing i would check is to take a OHM reading with a volt meter. To do that you must take the sending unit out of the tank and hook one lead to the sending unit and the other to ground and see if there any resistance reading on the sending unit. The reading should change as you move the float on sending unit slowly up or down. The OHM reading is determined by which sending unit you may have. Do you know what the OHM reading is for your sending unit ??
 

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FFCobra Craftsman
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Are you sure you have power and ground to the fuel gauge? With the connector removed from the sending unit, the gauge should peg to the top of the scale. If it doesn't, you have a problem with the wiring or the gauge.
 

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Greg,

An Autometer fuel gauge has three posts. Viewed from the rear; the left on goes to the sender's yellow wire, the center one goes to ground, and the right one goes to a switched 12V source.

As PAB said, power up the gauge and remove the sender line from the left-most post. The gauge needle should slowly rise past Full.

As Kenny said, check the sender by connecting an Ohm meter between the black and yellow wires. I assume you have the sender out of the tank, move the float to the lowest postion and it should read about 15 Ohms. Move it to the highest postion and it should read about 160 Ohms. If if doesn't work like this then it's bad-period.

Now, if it's bad, you can take it apart by heating the plastic "rivets" and takin the wiper arm off the ceramic resistor and cleaning bith with a pencil erasor or 1000 grit paper and them with spray carb cleaner. Put it back together and restest. OR just buy a new one. Mine was from a donnor and had a couple of wierd readings around 1/2 full so I cleaned it as described and it works great now.

Goog luck.
 

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Man I read my post and it must be early because my spelling is [email protected] Sorry, I'm not awake yet.
Greg
 

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Supreme Cobra Commander
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Greg, you're right too early. I hadto read it twice just to find your errors. TMT- Too much turkey.
 

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Which guages?
I have had and still have issues with the donor sending unit and donor gauge. Mine first one had the known "more than a quarter tank is full" syndrome. The replacement sender - another used one is now always empty.

Is the sender in the tank and is the tank in the car? If so you have to do detective work. You have three areas to deal with. The sender itself, the wires, and then the gauge. If the tank is in the car you can do a lot of test without pulling it.

Start with
Plug off the sender - gauge reads full
Plug shorted at the sender end - gauge reads empty
- sender issue most likely is problem as the wireing and gauge are working.

If that doesn't work meaning the guage does not indicate change,
Test wire run
From the gauge end measure -
Plug off - open or very high resistance
Short plug - < 20 ohm or so
Wire is good from back to front- pointing toward the gauge - maybe hookup

Measure resistance at sender - is it within range and is the resistance about right for the amount of gas in the tank? Yes - another gauge issue indicator.

It is a debugging process, just take it step by step and don't jump to conclusions as you go along.

BTW - you really don't need a gas gauge to drive it.

Good luck
 

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Discussion Starter #8
Thanks to everyone who pinged in, after checking with a volt meter it was determined the sender was bad.After installing the new one everything seems to be working fine for now. I couldnt have done it without your guys help. THANKS AGAIN
 
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