Anyone else have a fuel gauge that goes down halfway almost instantly?

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muddybumper
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My tercel:: 1987 SR5
Location: Idaho

Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by muddybumper »

After I fill up my fuel gauge is back down to half way after about 50 miles usually. Anyone else have this happen?
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Nordical25
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My tercel:: 1x86, 2x87
Location: Finland

Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by Nordical25 »

I had also a bit lower readings after rebuilding my fuel tank gauge.

FSM (https://tercel4wd.com/fsm/1985T4WD.pdf) defines correct ohm readings for fuel gauge in different positions. Has it been always like that or has it changed suddenly?
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muddybumper
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My tercel:: 1987 SR5
Location: Idaho

Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by muddybumper »

It's been like this since I've owned the vehicle which has been about 3 years
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dlb
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My tercel:: '87 sr5, '83 dlx parts car
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Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by dlb »

I've found this to be pretty common on al25's. I found that removing the fuel sender (if possible -- the screws fastening it to the tank are often completely rusted away) and cleaning the contacts helped a bit but even then, the readings were never terribly accurate.
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Nordical25
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My tercel:: 1x86, 2x87
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Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by Nordical25 »

I agree with dlb on rust especially if car has been used at salty areas. I had a leaking fuel tank needed to be replaced so I used drill to get my fuel sender out.

If tank is rust free you may get tank assembly down and see if you can open fuel sender screws. But it may result into ordering another sender unit or finding complete spare fuel tank so it is a good question if it is worth the effort.
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MrWrench
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My tercel:: 1985 Tercel SR5. aka Spud
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Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by MrWrench »

New aftermarket sending units are available o eBay. They’re around $60-$70 shipped. I have one in my 86 but I haven’t tested it yet unfortunately.

This is always an option if you’re unable to clean or repair your current unit.
1984 SR5. Lifted offroader with a snorkel. Aka "Thunderbucket"
1985 SR5. Daily driver. Aka "Spud"
1986 SR5. Dakar Rally clone build.
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by Petros »

sound like the resistance coil is worn away just below full on the sender. sometimes taking it out and cleaning the contact helps. I have also bent the little arm with the contact on it so it made better contact with the resistance coil also helps.

but if the coil is worn away, there is not much you can do about it other than to replace it. if you can find the same resistance wire you might be able to re-wrap the coil, but I think replacing it would be less trouble.

good luck
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)
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Ace
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My tercel:: '83 DLX 4WD Tercel wagon 3AC

Re: Anyone else have a fuel gauge that goes down halfway almost instantly?

Post by Ace »

Over time my Tercel fuel gauge readings have become less accurate and less consistent. I used to get about 200 highway miles on a full tank before the gauge reading dropped to the halfway mark. Now the readings are lower, sooner. It hasn't been enough of a problem to motivate me to troubleshoot or take things apart. My MPG is fairly consistent so I just reset the trip odometer at each fill-up and watch the mileage.
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