87 R 10 Fuel Gauge Problem

[5150]

I bought this truck back in February and the gauge has always bounced around. I've ran out of gas a few times and I was obviously tired of it. When it was low it would sit still at empty, but it was a short warning .

I bought a new Spectre sending unit/pump and installed it. Now the gauge sits a little past full at 2:00 and doesn't budge for anything. I grounded the pink wire, but it still didn't move.

Thoughts?

[pontgta]

Dual fuel tanks?

[5150]

Negative

[pontgta]

If disconnected the sending unit wire(pink), and grounding it does nothing. I think your guage has gon bad. I would take the guage out and test continuity from the pink wire to the terminal in the cluster to rule out bad wiring.

Also Member Hatzie has wiring schematics download those.....great help to test points and connectors

[motornut]

my 78 stopped bouncing when i swapped to gauges from idiot lights.
i had to change the gauge and it needed it's own ground.
I didn't change the tank or sender.
79 didn't bounce,before new tank and sender,still dosn't
the 78 has spectra,and the 79 I put spectra in.
some claim it's the spectra parts,but i think its a ground on the gauge issue
and yes I know the 87 is a electric tank mounted pump.
pump and sender use the same ground.(check it)
ground the sender it should read empty,off over full.

[tucsonjwt]

When I put Spectra sending units in my dual tanks the gauge started bouncing. I think Delco sending units would not do that, but they are $100 more. The gauge always returns to a proper level when the truck is stopped, so I can live with it. Previously, my gauge would stick near the full mark, then drop precipitously when near empty. A new gauge from LMC fixed that.