Fuel Gauge issues
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Freshman User
Joined: Oct 2009
Posts: 49
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From: York, PA
Fuel Gauge issues
The fuel gauge on my 78 f150 will not work at all anymore. It used to work everynow and then, but I replaced the sending unit in the tank to fix it and now it does not work at all.... My turck has dual tanks, but I only use the front, and I was wondering if the switch inside the truck to choose tanks would be a possible problem? Because the rear tank is always empty which is what my gauge reads. Any ideas? Thank you, Bobby
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
It's possible the switch is bad; it's also possible the frame cross-member has lost ground. Turn the ignition switch to accessory, pull the sending unit wire off the sending unit and ground it. The gauge should peg to FULL. If it doesn't, there's no power to the gauge, or there's no longer a ground back there.
Senior User
Joined: Jan 2010
Posts: 133
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im actually havin the same problem, i recently dropped my fuel tank, when i put it back in, no more fuel guage. i tried regrounding it to..nothing. Maybe try replacing the wiring harness that plugs into the sending unit, i think thats what im gonna do. they have them on broncograveyard.com for like 12 bucks.
Senior User
Joined: Feb 2009
Posts: 328
Likes: 0
From: northwest,WA
im actually havin the same problem, i recently dropped my fuel tank, when i put it back in, no more fuel guage. i tried regrounding it to..nothing. Maybe try replacing the wiring harness that plugs into the sending unit, i think thats what im gonna do. they have them on broncograveyard.com for like 12 bucks.
you should be able to ground the wire that travels the frame to the sending unit. when you do that you should read over full on the gauge. if it isnt working try a real ground run a long wire from the negative of the battery, or a 100% known ground like a trailer hitch and test again. if still nothing then you have a bad meter or dash-console connection. your 5v regulator could be bad (but you should notice this with other gauges)
I have a separate issue, I am about to drop my tank because I think my float is sunk. it is reasonable to pull the sending unit and solder/repair the float so it floats on top again?
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The sunken float is annoying. I pulled my tank to replace the factory sending unit because of a sunk float, only to have the replacement sink a week later. You can repair the float yourself; you can also replace the float entirely (without getting an entire sending unit). The float might even be available from Ford; if so I'd go that route.
I had to re-ground the sending unit to the bed sheetmetal to get it to work.
I had to re-ground the sending unit to the bed sheetmetal to get it to work.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
The sunken float is annoying. I pulled my tank to replace the factory sending unit because of a sunk float, only to have the replacement sink a week later. You can repair the float yourself; you can also replace the float entirely (without getting an entire sending unit). The float is available from Ford.
Solder breaks down, gas seeps in, float slowly settles to the bottom of the tank.
COAZ9202B .. Fuel Sending Unit Float / Available from Ford.
Fits ALL: 1957/79 Passenger Cars, Trucks, Bronco's and Econolines.
MSRP: $13.17 // FTE sponsor PARTSGUYED.COM price: $9.48.
Senior User
Joined: Feb 2009
Posts: 328
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From: northwest,WA
The float is made from two pieces of copper soldered together.
Solder breaks down, gas seeps in, float slowly settles to the bottom of the tank.
COAZ9202B .. Fuel Sending Unit Float / Available from Ford.
Fits ALL: 1957/79 Passenger Cars, Trucks, Bronco's and Econolines.
MSRP: $13.17 // FTE sponsor PARTSGUYED.COM price: $9.48.
Solder breaks down, gas seeps in, float slowly settles to the bottom of the tank.
COAZ9202B .. Fuel Sending Unit Float / Available from Ford.
Fits ALL: 1957/79 Passenger Cars, Trucks, Bronco's and Econolines.
MSRP: $13.17 // FTE sponsor PARTSGUYED.COM price: $9.48.
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Fleet Mechanic
Joined: Feb 2007
Posts: 1,326
Likes: 48
From: Middle TN
It's possible but you have to find the leak and get 100% of the gas out of it or it could go BOOM!!!
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Senior User
Joined: Feb 2009
Posts: 328
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From: northwest,WA
only down side is if its vapor locked then you gotta re-solder it all back together after it pops like a firecracker ha!
but seriously, yes. I was going to drill a hole in it to clear it of all vapor then clean it with alcohol air dry for a day or so in the sun and problem solved then just solder it up.
or just spend the 5-12 bucks for a new float.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 783
From: Simi Valley, CA
But...it won't be long, because... Sooner or later, usually sooner, the float will fill up with gas, and to the bottom of the tank it will sink.
Step up and buy a new float...for $9.48 from FTE sponsor PARTSGUYED.COM.
PARTSGUYED aka Y2KFORDPARTS.COM = Ed Olson, parts manager at MILLENNIUM FORD in Seattle (Burien) WA
You will also need this: COAF9276A .. Fuel Sending Unit O-Ring Gasket / MSRP: $0.85 // PARTSGUYED.COM price: $0.66.
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