Author Topic: 73 Caprice fuel gauge  (Read 845 times)

Offline gwcrim

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73 Caprice fuel gauge
« on: May 27, 2024, 06:40:06 PM »
Not really sure where to ask this question, so here it goes.

I have a nice 1973 Caprice convertible.  The fuel gauge is getting stuck on full.  Every now and then (usually after a hard turn) it will dip down and show what I hope is an accurate reading but then it goes back to full.  If the float was bad, it would read empty all the the time I would imagine.  What could be causing this situation?
« Last Edit: May 27, 2024, 06:44:09 PM by gwcrim »

Offline Captkaos

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Re: 73 Caprice fuel gauge
« Reply #1 on: May 28, 2024, 08:06:44 AM »

Offline gwcrim

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Re: 73 Caprice fuel gauge
« Reply #2 on: May 28, 2024, 09:20:11 AM »
I skimmed through that post to educate myself on the operation of the system.  I'm not super good with electronics, so please bear with me. 

A full tank creates higher resistance that makes the gauge read full, right?  So if there's failing ground, the gauge would read full?

My thinking is that, at 51 years old, the ground strap might be the culprit.  In order to test that, I could access the gauge wire under the dash and look for resistance of more than 88 ohms with a full tank?

Offline Mike81K10

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Re: 73 Caprice fuel gauge
« Reply #3 on: May 28, 2024, 11:57:02 AM »
The Fuel Sending Unit in the older trucks and vehicles can get gummed up and rusted over time. The tanks would rust from moisture and ethanal gas did not help when it came out. If your sending unit and/or fuel tank has not been inspected, it might be a good place to go.

The pics of the sending unit that was in my truck is shown below and my truck was still running and driving at the time, probably not for long. The corrosion buildup does have an effect on the gauge.
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