71 Coupe gas gauge not working - MustangForums.com


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Old 02-27-2012, 10:57 PM   #1
Liam
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Default 71 Coupe gas gauge not working

I recently got a 1971 Mustang Coupe and the gas gauge does not work. Regardless of the amount of gas in the tank it sits on empty. This is my first 71 so I'm not knowledgeable about the car. If anyone has dealt with this maybe a few pointers. Figured I'd ask before I started digging in. Thanks guys
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Old 02-27-2012, 11:07 PM   #2
rmodel65
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its probably the float that is on the arm of the sending unit...new gas is corrosive and will eat though them....the float is about 6$ from any mustang parts house
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Old 02-27-2012, 11:13 PM   #3
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Not to thread jack, cause this might apply to OP as well

Does the tank need to be empy to remove the sending unit to replace the float?
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Old 02-28-2012, 04:09 PM   #4
jlg2002
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oxford, yes the tank needs to be fairly empty to take the sending unit out (unless you really like the aspects of wearing that nasty gas smell for the next few days ) because it mounts on the front face of the tank.

Liam,
you need to check your fuel gauge circuits before you arbitrarily assume it's a sending unit (the problem could be the gauge, wiring or inst. Pnl connections, etc...)
with the key off and the rear of the car jacked up so you can access the rear axle area from underneath, locate the fuel tank sending unit wiring and pull it off of the tank unit, turn the ign key On and the gauge should go past full. turn the key off and attach a jumper wire from the loose fuel tank wire to a good ground (usually one of the tank mount bolts or exhaust hanger) turn the key on and the gauge should be below E. This check proves out the gauge wiring, inst pnl connection and power circuits. If the gauge doesn't go full scale when the wire is off, you most likely have a bad gauge or power issue
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Old 02-28-2012, 11:03 PM   #5
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Alright, I figured it was the float but I did notice today that when I put a few gallons of gas in the car and got in, it read about half full which is where it should have been, then as I drove it dropped back to empty and stayed there. I will definitely do as you recommended and check the circuits first. I knew that can happen but I had no idea how to check for it. Thank you very much, I will hopefully get to it in the next few days and let you guys know.
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Old 02-28-2012, 11:31 PM   #6
rmodel65
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well the float might have emptied the gas inside when the tank was low then when you put some gas in it floated for a while then sank....but you can definitely check the circuit but every classic stang ive had has needed a float and not anything else
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Old 02-29-2012, 11:45 PM   #7
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Like I said, I may as well check the the circuit to be sure. The only way I know how to remove the sending unit and float is to remove the entire tank. Maybe it's a dumb question but is it possible to replace the float without removing the tank from the car? Thanks again.
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Old 02-29-2012, 11:55 PM   #8
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Quote:
Originally Posted by Liam View Post
Like I said, I may as well check the the circuit to be sure. The only way I know how to remove the sending unit and float is to remove the entire tank. Maybe it's a dumb question but is it possible to replace the float without removing the tank from the car? Thanks again.

http://www.mustangmonthly.com/howto/...t/viewall.html
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