Gas gauge reads too high - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

 
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post #1 of 4 (permalink) Old May 11th, 16, 3:39 PM Thread Starter
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Gas gauge reads too high

I have a '72 model that has been sitting for a long time. I started it up and noticed that the gas gauge went immediately to above the FULL mark. What could that be caused by?
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post #2 of 4 (permalink) Old May 11th, 16, 3:53 PM
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Jim
 
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Re: Gas gauge reads too high

I would check the connections at the tank - particularly the ground. After sitting for a while, you may have a dirty connection. I may have this backwards, but I believe the gauge reading full is an open circuit where as complete ground would read empty. Anything in between is based on the resistor on the float.

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post #3 of 4 (permalink) Old May 11th, 16, 4:11 PM
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Re: Gas gauge reads too high

Quote:
Originally Posted by Jim's69Ragtop View Post
I would check the connections at the tank - particularly the ground. After sitting for a while, you may have a dirty connection. I may have this backwards, but I believe the gauge reading full is an open circuit where as complete ground would read empty. Anything in between is based on the resistor on the float.

jim
Approximately 90 ohms from tan sending wire to ground is a full tank, zero ohms to ground is empty. Anything much above 100 ohms will peg the gauge beyond full. I agree, an open ground at the tank or the gauge is usually the problem, but the resistance element in the sender or the gauge itself could also be defective. This guy shows how to troubleshoot all parts:

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post #4 of 4 (permalink) Old May 11th, 16, 4:44 PM Thread Starter
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Re: Gas gauge reads too high

I am thinking evil thoughts here. I may have some wires chewed through by pack rats, as there is one turn signal/brake lamp that is also out.
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