Gas Guage question
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Gas Guage question
On my 85 f-150, the gas guage only works until I use 8 gallons worth of fuel. After that It goes to empty. Is that a problem with the sending unit or what. I'm not sure if it is the same on both tanks, because my front tank has a hole in the filler tube, so i've never filled it up completely.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
that is either sending unit, or the float has a pinhole in it that has let some into it, throwing off the readings. A cheap fix for that is to use a small pill bottle in the place of the float...
Post Fiend
Joined: Jul 2004
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From: Northern California
Every 1980 to 1986 F-series, I have ever seen has a faulty gas tank sending unit in some way.
My front tank on mine reads over full when full, reads correctly at 1/2 and has 5 gallons in it left when it reads "below" empty, and when it raises back up to the empty mark, it is empty. :S
The rear tank reads 75% when full, and when the gauge reads empty, you better have gas in the other tank or get some imediatly at a gas station cause it means what it says!
(You know I've ran out of gas with a two tank rig more often than I ever did with a single tank rig. Interesting that. )
My question is where can you get good inexpencive aftermarket sending units? Wrecking yard is out of the question cause the odds of getting a bad one are too high for all the work you have to do... and ford wants more than I can really afford to replace them.
My front tank on mine reads over full when full, reads correctly at 1/2 and has 5 gallons in it left when it reads "below" empty, and when it raises back up to the empty mark, it is empty. :S
The rear tank reads 75% when full, and when the gauge reads empty, you better have gas in the other tank or get some imediatly at a gas station cause it means what it says!
(You know I've ran out of gas with a two tank rig more often than I ever did with a single tank rig. Interesting that. )My question is where can you get good inexpencive aftermarket sending units? Wrecking yard is out of the question cause the odds of getting a bad one are too high for all the work you have to do... and ford wants more than I can really afford to replace them.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
Well, I haven't got them in yet, but what i did was ordered senders from JC Whitney, the universal style for $16 99 each, (part #AJP128525U) then I am going to take the senders off their mount and put them on the factory sump, it looks like it will work pretty slick. I'll have to let you all know how it works out after I actually do one. Both of mine have been on the fritz, so I track mileage to keep from running dry. My front tank at first showed full only when it was, and showed empty by 1/2 tank, the rear was kinda accurate. Well, then the front quit reading at all, always showed empty, and the rear was empty by about 1/2 tank actual... so i figured the senders had to be bad, as no other guage problems are present. They shift a little, but not that drastic.
Last edited by fellro86; Jun 12, 2005 at 11:16 PM.
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Originally Posted by 81-F-150-Explorer
Every 1980 to 1986 F-series, I have ever seen has a faulty gas tank sending unit in some way.
My front tank on mine reads over full when full, reads correctly at 1/2 and has 5 gallons in it left when it reads "below" empty, and when it raises back up to the empty mark, it is empty. :S
The rear tank reads 75% when full, and when the gauge reads empty, you better have gas in the other tank or get some imediatly at a gas station cause it means what it says! (You know I've ran out of gas with a two tank rig more often than I ever did with a single tank rig. Interesting that. )
My question is where can you get good inexpencive aftermarket sending units? Wrecking yard is out of the question cause the odds of getting a bad one are too high for all the work you have to do... and ford wants more than I can really afford to replace them.
My front tank on mine reads over full when full, reads correctly at 1/2 and has 5 gallons in it left when it reads "below" empty, and when it raises back up to the empty mark, it is empty. :S
The rear tank reads 75% when full, and when the gauge reads empty, you better have gas in the other tank or get some imediatly at a gas station cause it means what it says!
(You know I've ran out of gas with a two tank rig more often than I ever did with a single tank rig. Interesting that. )My question is where can you get good inexpencive aftermarket sending units? Wrecking yard is out of the question cause the odds of getting a bad one are too high for all the work you have to do... and ford wants more than I can really afford to replace them.
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Posting Guru
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From: Niceville, FL.
I have the JC Whitney sending unit on my '83 F350 with 22 gallon mid-ship (outside frame) tank. Its five screw mounting matched my tank exactly. Don't know if you could convert a Ford sender to use the Whitney electrical parts though. When mounting the unit you have to adjust the float arm length and pivot point position. At Empty I have ~3 gallons remaining and at 20 gallons guage reads Full. Can't remember exactly but I think 13 gallons registerd 1/2. The resistance part of this era Ford gauges (0-80 Ohms) are all the same I think so you can swap those parts around but float arms vary considerably. If you take one apart be very careful; the resistance wire is very, very fragile. On all 0-80 Ohm Ford sending unit (oil pressure, fuel, water temp) 73 Ohms make the gauge read at low mark and 10 Ohms at high mark according to my ford manual.
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Originally Posted by 81-F-150-Explorer
Every 1980 to 1986 F-series, I have ever seen has a faulty gas tank sending unit in some way.
Posting Guru
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From: Niceville, FL.
Ritterpa,
That's really strange since fuel, oil pressure and temperature gauges are all fed from the same instrument panel voltage regulator. I haven't a clue as to why only one would act up based on key position unless someone has done some non-stock rewiring.
That's really strange since fuel, oil pressure and temperature gauges are all fed from the same instrument panel voltage regulator. I haven't a clue as to why only one would act up based on key position unless someone has done some non-stock rewiring.
Freshman User
Joined: Jan 2005
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From: Alabama
I have an 86 EFI 302 and the gas gauge is as most people have described inaccurate below 1/2 tank. This seems to be a pretty typical problem on these trucks. I haven't pulled the sensors yet but when I do I will post to let everyone know whether or not replacements units solve the problem.
Posting Guru
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From: Niceville, FL.
From playing around with some of the 80-86 Ford fuel sending units it appears to me that the resistance is pretty much linear with respect to float arm angle. My opinion is that a lot (if not most) of the inaccuracies are due to the odd shapes of the tanks.
Hotshot
Joined: Feb 2004
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From: Marengo, Iowa
There is that, but originally they read fine, but over time they go kaput. Amazingly, my dad's truck still reads about right after 21 years of service, but it has gotten to where if it reads 1/4 tank, best be filling... my rear kinda works, and the front has started reading again when it feels like it, but still shows empty with plenty of fuel in it. I have run 100 miles after it shows empty... that's why I track my mileage and make sure there is some backup fuel in the other tank...