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Old 08-03-2016, 11:05 PM   #1
matthew21lutz
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Exclamation Fuel Gauge "Bouncing"

So I've searched this and found a few but, I just want to be clear on what I need to do before I have to pull the tanks.

The problem is once the truck is running the fuel goes anywhere from 1/4 of a tank to full and bounces all over the place. So is it the gauge? The Sending unit? I don't believe it's a ground near the gauges, I found the splice and everything looks great, maybe it's a ground elsewhere? I really need some help here as I really don't want to drop both tanks including the driver side is 3/4 full.
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Old 08-03-2016, 11:11 PM   #2
tommy217xxx
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Re: Fuel Gauge "Bouncing"

I had some issues with my gauge not working. intook the gauge out of the cluster and sanded the terminals on the gauge. Check the printed circuit also. I ended up buying a nicer cluster for my truck and the gauge started working.
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Old 08-03-2016, 11:57 PM   #3
ron350
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Re: Fuel Gauge "Bouncing"

Might not help with your specific problem but good reading on the subject.

http://67-72chevytrucks.com/vboard/s...d.php?t=640615

http://67-72chevytrucks.com/vboard/s...d.php?t=668356
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Old 08-04-2016, 02:07 PM   #4
ron350
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Re: Fuel Gauge "Bouncing"

Matthew21lutz I forgot to ask if your fuel gauge pointer bounces around with the truck running but sitting still in the driveway?
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Old 08-04-2016, 06:36 PM   #5
tucsonjwt
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Re: Fuel Gauge "Bouncing"

There are lots of theories on this. I attribute mine to cheap Spectra brand sending units. I would install AC Delco sending units if I had the same problem, which are about $100 more per sending unit.
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Old 08-04-2016, 06:56 PM   #6
hatzie
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Re: Fuel Gauge "Bouncing"

Things to try...
One theory about the cheap sender units is the float arm is not making good electrical contact with the sender body. Why is that important? The rheostat wiper is attached to the float arm and uses that part as its' ground. Solder a braided copper strap from the float arm to a non moving metal portion of the sender.

Some speedometer and gauge repair shops will inject a thick non hardening silicone damping gel into the core of the meter around the shaft.
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Old 08-04-2016, 07:23 PM   #7
matthew21lutz
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Re: Fuel Gauge "Bouncing"

Quote:
Originally Posted by ron350 View Post
Matthew21lutz I forgot to ask if your fuel gauge pointer bounces around with the truck running but sitting still in the driveway?
If the truck is running and sitting still, it bounces less but still bounces.
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Old 08-06-2016, 12:47 AM   #8
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Re: Fuel Gauge "Bouncing"

I had the exact same problem. Got under my square and began to trace the wiring from front to rear. Right under the passenger door, the wiring was held by a factory clip that had chaffed the wiring, causing it to short out against the frame. A bit of electrical tape and problem solved.
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