Fuel gauge reading full all the time

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Kpete856

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My fuel gauge is full at all times, I have apprx. 1/4 tank of gas. I replaced the sending unit as suspecting this as the problem. I have read through several threads on this site and performed all the troubleshooting tips to no avail. My grounds are good my gauge is functioning, I ohm check the new sender and ohms check fine. I ran a temporary sender wire frome gauge to sender with no change. I have 12 volts on I terminal and 8 volts from S to Grnd. Does this sound correct. Any information would be helpful.
Thanks
 

Silvertip

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Re: Fuel gauge reading full all the time

Does it read full with the key OFF as well? If it does, the gauge is stuck and must be replaced. If not, it is probably shorted internally as the tests you indicate appear normal.
 

Kpete856

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Re: Fuel gauge reading full all the time

Does it read full with the key OFF as well? If it does, the gauge is stuck and must be replaced. If not, it is probably shorted internally as the tests you indicate appear normal.

With the key off the gauge reads empty, I was thinking the sender itself was possibly shorted internally. Checking the sender unit out of the tank with the key switch on I can see movement on the gauge well above the full mark, never going below full though.
 

dingbat

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Re: Fuel gauge reading full all the time

Did you try reversing the wires?
 

Silvertip

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Re: Fuel gauge reading full all the time

In your original post you said you checked the sender resistance and it is fine. So an internal short in the sender is not a possiblity IF you actually measured the resistance and it is 30 240 ohms as you swing the arm. If not, you have a bad sender. If a sender works outside the tank but not when installed, it usually means the float is hanging up on something in the tank. So you need to be sure the sender is good or not.
 

02 Silverado

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Re: Fuel gauge reading full all the time

Kpete856, if you find a resolution to your gauge reading problem, let me know please, sir. I have an identical issue. I put in a new sender, ohms readings across the sender are within manufacturer's specifications range. Before inserting the float are, it seemed to travel freely. It's hard to imagine that the float travel is obstructed inside the tank.
 

Silvertip

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Re: Fuel gauge reading full all the time

What happens if you disconnect the sender wire from the "S" terminal on the gauge?
 

Sixmark

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Re: Fuel gauge reading full all the time

Kpete856, if you find a resolution to your gauge reading problem, let me know please, sir. I have an identical issue. I put in a new sender, ohms readings across the sender are within manufacturer's specifications range. Before inserting the float are, it seemed to travel freely. It's hard to imagine that the float travel is obstructed inside the tank.

Please post your issue under it's own thread, hijacking another thread only adds to the confusion.
 

RLandis

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Fuel gauge was always reading full. Replaced old gauge and old sending unit in the tank. Gauge still reads full when it is nearly empty? New sending unit reads low ohms when at the bottom of the shaft and higher ohms when at the top- just the opposite of what i read it should say. The old unit reads high ohms at the bottom (185) and lower at the top. Why no change in fuel tank gauge reading after changing both parts??
 
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