Fluctuating fuel gauge

[Matt Bachand]

I have cleaned every ground under hood that I can find.

When I cycle my key on and off, my fuel guage spins around in 360's. When I drive it is erratic. Any ideas on where the fuel read grounds? I just put a brand new frame to dash ground, as well as a engine to ground.

[nintyfourTsixfive]

correct me if im wrong but isnt there a ground from the frame to the fuel tank... for the sending unit

[sixnickel]

I am not 100% sure on the diesels, but I know on gasoline GM trucks, fuel tank grounds are on the left rear frame rail. The same bolt grounds the tailight harness. Kind of a wacky way of doing it, and I found that one the hard way. I took a body off a truck to change the fuel pump, and the truck wouldnt run with the new pump because I pulled that bolt out for the body grounds. Chalk it up to experience.

Sixnickel

1999 K1500 Suburban
40 HP BD computer
SS Diesel Air Intake
FSD Cooler

2000 K3500 SRW
SS Diesel Power Pack
FSD Heat Sync