another fuel guage question
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Freshman User
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another fuel guage question
1988 F-150 4.9 efi
front tank reads over full all the time, r4ar reads empty all the time. question is - is reading empty an indication of open circuit or is it a short?
front tank reads over full all the time, r4ar reads empty all the time. question is - is reading empty an indication of open circuit or is it a short?
Senior User
Joined: Jul 2004
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here in the rust belt I have found that when a fuel gauge reads way past full..its usually a lost ground because of corrosion...either on the sending unit terminal ot the frame where its grounded.........its almost a given here that old truck dont have reliable fuel gauges....fix the ground & its fixes the reading.
Senior User
Joined: Jan 2004
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From: Orange County, CA
Sounds like my 88. Been that way since I bought it in 1995. I had it at the dealer for some work and asked them to check the gauge problem. Ended up being the sending units. I keep thinking I'll have it fixed one day, but until then I'll keep using my odometer.
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Joined: Feb 2007
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On my 88 Mustang years ago the gauge read past full when the sender failed (open circuit). I found the sender wire in the trunk and cut it. Then spliced in a 50ohm resistor from Radioshack that cost about $2 to give the illusion that the tank had gas. The gauge then read somewhere between 1/2 and F. I believe the Ford resistance range is usually 0ohms (empty) - 75ohms (full) or so. Anyway with this test I knew the sender was bad. Bought a new one and replaced it and its worked longer than the original at this point.
HTH
88 Mustang
1/2 of a 90 F250HD
HTH
88 Mustang
1/2 of a 90 F250HD
Last edited by spacemn2; Mar 1, 2007 at 12:16 PM. Reason: spelling
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