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**hatzie** · 06-17-2011, 08:35 PM

I read the same thing in one of my mid 70s Chevrolet Service News publications. GM re-calibrated the CK truck fuel gauge and sender system around somwhere between 74 & 78 so that F-1/2 was more like F-5/8 or F-11/16. That makes 1/2-E actually 3/8-E or 5/16-E in the tank. That's why the bottom half of the gauge drops so fast.
A direct result of the artificial OPEC oil shortages in 1974.

Back on topic.

A loose or pinched sender wire and a loose or missing ground will cause the gauge to peg intermittently. The tank can still ground poorly through contact on the straps and frame. I had this happen with my 1985 C10 after i replaced the tank. The ground was completely missing from the old tank. After I installed a ground strap from the frame to the sender my problem went away.

06-17-2011, 08:35 PM	#12
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 5,020	Re: Gas gague troubles. I read the same thing in one of my mid 70s Chevrolet Service News publications. GM re-calibrated the CK truck fuel gauge and sender system around somwhere between 74 & 78 so that F-1/2 was more like F-5/8 or F-11/16. That makes 1/2-E actually 3/8-E or 5/16-E in the tank. That's why the bottom half of the gauge drops so fast. A direct result of the artificial OPEC oil shortages in 1974. Back on topic. A loose or pinched sender wire and a loose or missing ground will cause the gauge to peg intermittently. The tank can still ground poorly through contact on the straps and frame. I had this happen with my 1985 C10 after i replaced the tank. The ground was completely missing from the old tank. After I installed a ground strap from the frame to the sender my problem went away.