Gas Gauge help
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Freshman User
Joined: Dec 2008
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Gas Gauge help
Guy's,
About a year ago, I bought my F250 Super Cab, 4 wheel drive. Some of the repairs I found are dubious at best.....The latest thing to fix is the gas gauges.....They both peg at full when I turn the key on. Any thoughts?
Thanks,
Pat
About a year ago, I bought my F250 Super Cab, 4 wheel drive. Some of the repairs I found are dubious at best.....The latest thing to fix is the gas gauges.....They both peg at full when I turn the key on. Any thoughts?
Thanks,
Pat
Junior User
Joined: Nov 2009
Posts: 53
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How many grounds are in the circuit? Cause my gauge doesn't move at all or will work sometimes. I replaced the gauge during the summer and it still will not work. Its the only gauge in my whole cluster that isn't working.
Posting Guru
Joined: Sep 2003
Posts: 2,313
Likes: 12
From: Northeast LA
Your's may just be a problem with the float having a hole it in and filling up with gas and sitting on the bottom of the tank. I've had to replace the float in my tank twice. Just my .02 and a suggestion.
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Freshman User
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Thanks for the input guy's. Much appreciated......I took a look at the aux tank reading.....Zero. Probably a sunk float. I'll do some digging further on back for the main tank.
Thanks again,
Pat
Thanks again,
Pat
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The only ground is supposed to be downstream of the sending unit. The sending unit is essentially a rheostat in between the gauge and ground; it varies in resistance which in turn varies the current going through the sending unit. The swing of the needle in the gauge is proportional to the current going through the sending unit.
On these trucks:
Full tank = low rheostat resistance = high current flowing through the sending unit = far needle swing (toward F).
Empty tank = high rheostat resistance = low current flowing through the sending unit = minimal needle swing (toward E).
Any other ground in the circuit is unwanted and will peg the needle to F.
On these trucks:
Full tank = low rheostat resistance = high current flowing through the sending unit = far needle swing (toward F).
Empty tank = high rheostat resistance = low current flowing through the sending unit = minimal needle swing (toward E).
Any other ground in the circuit is unwanted and will peg the needle to F.
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Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
Solder breaks down, gas seeps in, float slowly settles to the bottom of the tank.
COAZ9202B .. Fuel Sending Unit Float / Available from Ford.
MSRP: $13.17 // FTE sponsor PARTSGUYED.COM price: $9.48.
Fits: All 1957/79 Passenger Cars, Trucks, Bronco's and Econolines.
Since this same float fits all these vehicles, all are subject to the same problemo...which is a very common occurence.
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Freshman User
Joined: Dec 2008
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So, a little update....I found the short for the rear gauge. One of the bolts holding the strap was tightened down, smashing the the crap out the wire, therefore creating a short. That problem is fixed. One down, one to go. Thanks for the help fella's
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Freshman User
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One more upadte.... I made a mistake in the original post. The rear tank would peg at full...Short found and fixed....The front tank was sitting on empty. I checked the float...it worked okay...I plugged in a spare sender from a donor. Float good. I set up the sender at the full position...Gauge read fulll..... It was a bad reostat (sp?) on the orginial sender. I'm a happy camper. Two functional gauges now. Thanks to all for your insights.
Pat
Pat
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Joined: Dec 2007
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From: Mandan, ND
Just putting in my two cents... with regard to ethanol. I think it should be avoided in a anything with a carb. It seems like it dries out the diaphrams in fuel pumps, carb gaskets, eats away at old fuel lines, etc. My guess with the old brass floats is that the solder joints get weak over time from vibration or whatever and the alcohol cleans all the gunk off them and they leak. I just seem to have a lot less trouble running regular unleaded. I was wondering if anyone else has an opinion one way or the other. By the way I don't mean to undermine renewable resources, or our nations farmers. I have no problem using ethanol in my newer efi equipped vehicles.
Freshman User
Joined: Sep 2009
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From: Wisconsin
I just came across this post and would like to ask a related question. I have a 79 F150 that the last owner replaced the rear fuel tank with a new steel tank. The middle tank was taken out and not replaced. Now the fuel gauge for the rear tank does not work (reads empty). How do I get the gauge to work?. It looks like all the wireing is still there for the middle tank. I don't plan to put a middle tank in if I don't need to.
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Freshman User
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So based on what I've learned in repairing mine (the dead one) Remove the sender from the tank (PITA) check the float to see if it floats. If it floats, plug it back into the harness, make certain that the gauge is grounded, prop it open to the full position, crawl out and turn the key to the on position. I was fortunate enough to have a spare sender handy to repeat the process, what I came up with was a a bad rheostat on the sender.
Regarding not having a middle tank....Is the line capped or was the selector soliniod removed as well?
Regarding not having a middle tank....Is the line capped or was the selector soliniod removed as well?
