Fuel Gauge swinging

[JCM5]

Does any one make a aftermarket buffer or something to keep the fuel gauge stable?

Replaced sending unit, original was bad for years. Now the fuel gauge works but, when you stop and go the gauge moves fairly rapidly to the sloshing of the fuel in the tank.

Tank parts were in tack, I checked everything before installing the new gauge. Before the original sending unit went out I had a stable gauge. Now, the gauge acts to the sloshing of the fuel.

Looking for some sort of Buffer to place between the gauge and Sending unit to help isolate the swings. Or was tha gauge damaged from the old sending unit?

JCM

[DennisG01]

I get (and always have) about 1/8 swing on the gauge due to sloshing (the gauge moves very slow, though). Do you get much more than that? Does the gauge move quickly? I know you said you checked tank parts, but maybe some of the internal baffles have broken? I would think these would be rather hard to check through only the sender opening. But I could be wrong - I've never checked, myself. Just a thought...

Someone correct me if I'm wrong as I'm assuming that these tanks have internal baffles.

[JetBoater]

I've noticed about a 1/8th swing in the gauge when it gets to the half mark. This feature is exhibited while stopping and starting, and traveling up and down hills.

The other issue I noticed with this gauge is that it is NOT proportioned properly.

1/2 tank = 20L (5 Gal)
3/4 tank = 50L (13 Gal)
Full mark = 80L (21 Gal)
Over full, swings the gauge to 1/4 over F = 100L (26 Gal).

Every car/truck I have ever owned always has always had more fuel in the top half of the tank than the bottom... this Silverado wins that prize.

[JCM5]

I looked inside the tank there is a plastic box that takes up about 1/3 of the tank. The box lets fuel in at the bottom. This is GMs slosh.

The tank "box" is fine from what I can tell.

The gauge "originally" never swung, worked liked every other truck i had.
Now the gauge swings, sometimes violently when stopping and going, otherwise its steady and reads correctly.

I,m wondering if there are types of sending units that null out the signal more then others, duall resistors or a float that slow responds to lift?

Does anyone have a electrical schematic of the circuit.

70ohm tank to the gauge, what is in the gauge side?

It has to be more then a wheastone bridge affair i hope.

Doed the Dash board have a buffer for this signal?

Cant live with this gauge swinging like it does, 1/8 swing as others have mentioned would be ok, but not a 1/2 tank when you slosh the fuel.

[diesel65]

There is a signal buffer in the instrument cluster, you would need to send it to a repair shop or get another cluster from a donor vehicle.

[hatzie55]

The other issue I noticed with this gauge is that it is NOT proportioned properly.

1/2 tank = 20L (5 Gal)
3/4 tank = 50L (13 Gal)
Full mark = 80L (21 Gal)
Over full, swings the gauge to 1/4 over F = 100L (26 Gal).

Every car/truck I have ever owned always has always had more fuel in the top half of the tank than the bottom... this Silverado wins that prize.

Chevrolet Service News ran an article about the "new" weighting of the fuel gauge in the mid 70s light trucks. The fuel gauge system was modified on GM pickup trucks because of consumer complaints about fuel mileage. At 14mpg the fuel gauge began to drop from the full mark soon after a fill up. They modified the fuel gauge system to "keep the tank full" for the first 1/3 tank of fuel.

My 2000 GMC runs almost 3/4 of a tank before the gauge moves and then drops like a rock. The full sweep is the bottom 1/4-1/3 of the tank. I find it extremely annoying to have to use the trip odometer because I can't trust the fuel gauge.

The gauge panel should buffer the swinging sender to some extent. Are you sure the baffles are still attached inside the tank?
You could try adding a small capacitor inline with the gauge wiring to smooth out the extremes from the sender.