Gas gauge still pegged - Team Camaro Tech
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post #1 of 5 (permalink) Old Jul 25th, 10, 01:50 PM Thread Starter
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Gas gauge still pegged

After taking two years on my '68 Camaro to do major mods (2004R, 8.5" Nova posi, Classic Auto Air, aluminum radiator, Autometer gauge pods) prepared for a road trip. Flushed the entire fuel line and siphoned all gas in tank. Peeked inside tank and float level seemed fine. The gas gauge is pegged at 3:00 way past full. Disconnected fuel sender brown wire and grounded it...gas gauge went to empty. Tried to trace the brown wire. It goes into the covered wire harness behind the trunk lock, across the rear panel, and along the driver side of the rear fender into the cab behind the rear seat. That is as far as I traced it without removing the seats.
My questions are: If I run a wire directly from the fuel gauge to the tank sender unit will this indicate how much fuel is in the tank? Can a fuel sender go bad from sitting two years with only half a gallon at most in the tank? The tank now has 4 gallons in it. Thank you for any suggestions on how to proceed.

Last edited by IRON MAN; Aug 7th, 10 at 01:29 PM.
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post #2 of 5 (permalink) Old Jul 25th, 10, 03:55 PM
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Re: Gas gauge stilled pegged

Terry its been my experience that whenever a gauge is pegged it is a GROUND problem. I recently knocked off the wire to my temp sending unit (in the head) and did not noticed until my temp. gauge was pegged all the way past Hot. At this point I don't think its the fuel sending unit. I would leave the brown wire grounded and fill up the tank and note the location of the gauge.
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post #3 of 5 (permalink) Old Jul 25th, 10, 05:36 PM
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Re: Gas gauge stilled pegged

You can either measure the sending unit to ground for approximately 22-25 ohms since there is four gallons in the tank.

You've proved the tan wire is not grounded as you disconnected it from the s/unit and grounded it at the s/unit and gauge went empty.

As Donny suggested, add more fuel to see what happens with the gauge indication. It should register more fuel.

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post #4 of 5 (permalink) Old Jul 26th, 10, 06:00 AM
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Re: Gas gauge stilled pegged

As Everett said the wiring from back to front is good. The problem lies at the tank somewhere. Check the ground at the tank before you add more fuel. If the senders bad you want the tank as light as possible when you drop it.

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post #5 of 5 (permalink) Old Jul 29th, 10, 01:45 PM
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Re: Gas gauge still pegged

Get a jumper wire with alligator clips on each end, clip one end to the metal fuel line coming out of the tank, the other end to the unibody, clip onto bare metal on each end. If the gauge doesn't indicate correctly with a good ground, then your sender is probably bad. The factory ground wire plugs into a spade prong where the tube exits the tank, and the other end is screwed to the unibody at the front anchor strap bracket.


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