1971 fuel gauge problem.HELP!!
Thread Starter
Instructor
Joined: Jul 2002
Posts: 110
Likes: 0
From: sarasota fl
1971 fuel gauge problem.HELP!!
trying to replace a fuel gauge in a 71 vert.ordered a new gauge from ecklers but when installed it does the same thing as the old one,it goes way past the full mark.both connections on the back of the gauge are testing hot and getting a full 12volts.any suggestions?
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Re: 1971 fuel gauge problem.HELP!! (jn79vette)
Pegged past full indicates an open circuit in the fuel sending unit wiring. Go out back and check the (going from memory here) tan wire at the sending unit on the tank. If you don't have +12v there, you've got a break in the wiring between the gauge and the sending unit.
If there is +12v at the sending unit, disconnect the wires from both sides of the sending unit. Check the resistance across the two terminals. It should vary from 90 ohms with the float up at "full" down to near zero ohms with the float at "empty". If you've got infinite resistance across the two terminals, the sending unit is bad.
Now if there is voltage at the sending unit, and the unit itself ohms out OK, then you've got a bad connection between the sending unit and ground. Jumper a wire from the ground terminal to the frame and see if the gauge comes back to a correct reading.
Now go lay down on the cold concrete and start digging in. Tell us what you find. :cheers:
Shannon
If there is +12v at the sending unit, disconnect the wires from both sides of the sending unit. Check the resistance across the two terminals. It should vary from 90 ohms with the float up at "full" down to near zero ohms with the float at "empty". If you've got infinite resistance across the two terminals, the sending unit is bad.
Now if there is voltage at the sending unit, and the unit itself ohms out OK, then you've got a bad connection between the sending unit and ground. Jumper a wire from the ground terminal to the frame and see if the gauge comes back to a correct reading.
Now go lay down on the cold concrete and start digging in. Tell us what you find. :cheers:
Shannon
Instructor
Joined: Jan 2002
Posts: 155
Likes: 0
From: Houston Texas
Re: 1971 fuel gauge problem.HELP!! (jn79vette)
The sender inside the gas tank has failed and needs replaced. Too bad, but you'll get a chance when you pull the tank to see if the build sheet is still there.
Safety Car
Joined: Jan 2001
Posts: 4,660
Likes: 3
From: South Central Louisiana
St. Jude Contributor
Re: 1971 fuel gauge problem.HELP!! (zwede)
:iagree:
Sender can be replaced without pulling tank on a 71. You must drain tank though. Check your connections at the sender first. Mine does similar to yours, it reads past full until the tank is empty then it goes to E. :lol:
Sender can be replaced without pulling tank on a 71. You must drain tank though. Check your connections at the sender first. Mine does similar to yours, it reads past full until the tank is empty then it goes to E. :lol:
Safety Car
Joined: Jan 2001
Posts: 4,660
Likes: 3
From: South Central Louisiana
St. Jude Contributor
Re: 1971 fuel gauge problem.HELP!! (77Dream)
I got a new center console printed circuit from ecklers and that did the trick for me. Part #25067
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Drifting
Joined: Dec 2002
Posts: 1,426
Likes: 1
From: San Diego, CA Website: ChrisMitchell.us
Re: 1971 fuel gauge problem.HELP!! (71,454,4spd)
Not used on a 71, that was the pre printed circuit era. :)
Racer
Joined: Jan 2003
Posts: 397
Likes: 0
From: Morganton GA
Re: 1971 fuel gauge problem.HELP!! (77Dream)
:iagree: The '71 can be removed from below without dropping the tank, drain the fuel and remove the sending unit. There is also a possibility that the sending unit could be having a problem as well... I guess that is one of those "while I am at it..." items...
Good Luck.
Good Luck.
