Fuel gauge serious fluctuation

[mdross1]

Tried the search,no luck.
Have a Stewart Warner fuel gauge and sender,as soon as tank fuel level starts down and gas sloshes around the gauge jumps all over the place.Is there an electrical cure for this or do I need to baffle the tank,or maybe even a different style sender?

[Ron61]

I had a different brand in mine and as soon as the tank got down to about 1/2 it would start to move around. I just put baffles in the tank and that cured the problem. On hard acceleration with just over 1/2 tank left, I could make it read empty and everything in between, including 3/4 tank when I slowed down and the fuel splashed back and forth.

Ron

[strictlypersonl]

It's been a few decades (OK - almost a half-century) since I took circuit theory, but I suspect that a large capacitor would dampen the sender's signal. Connect it from the sender signal circuit to ground to even-out the current going through the sender windings. Maybe someone with more expertise than me can give you a proper value. (For reference, the gauge compatible with the 33-270 ohm sender has about 100 base ohm internal resistance.)

[FWB]

ford used to put what they called a gauge cluster regulator in cars. basically it pulsed the electrical signal from the senders to eliminate erratic gauge movement. they were located near the gauge clusters of most cars. they are rather simple bi-metal type of unit.....get one from a 65 or 66 t-bird and wire it in. i use the t-bird for the example because i know they are a separate unit from the cluster and are probably available at a resto parts house.

i have the stewart warner gauge too, and mine moves all over the place. i just don't care, i'm too busy keeping the car on the road to notice it...lol

fred

[Rick Parker]

The Stewart Warner sending unit is just a wire arm with a float on it that moves up and down rapidly with the level of the fuel. As Ron61 suggested, baffles within the tank or some other means of "dampening" the movement of the arm (fuel level) will reduce the gauge fluctuation. For your particular application perhaps a different design sending unit might be advantageous.
Quite some time ago while doing some work on my own tank I realized whoever installed it had put it in upside down and the cutouts in the sheetmetal baffles within the tank were at the top, instead of the bottom to allow transfer of fuel from side to side. I inverted the tank, welded the original opening; and then replumbed it.

[mdross1]

Years ago took the tank down and had a drain welded in,thought about baffling but was also thinking there had to be something electrical that could be done since everyother gas tank in production vehicles were not baffled and their gauges were rock steady.