Gas guage fluctuation problem

[Eric M.]

This is the second truck that has developed this problem. An 82 full size and now an 87 full size. The gas guage fluctuates as you drive and go over bumps, come to stops and leave from stops. It will fluctuate as much as 1/2 tank. I know there must be a buffer which prevents this that has failed somewhere in the electrical circuit .... but where? I'm thinking it is built into the gas guage but can't find any info. in any of the service manuals. Anyone experience this and found a fix?

Thanks,

Eric M.

 

[tRustyK5]

Sounds like broken baffles in the tank.

Rene

 

[rjfguitar]

Mine fluctuates too but not a 1/2 tank. I will have a 1/4 tank when I get home and the next morning I have 3/8 or 1/8 of a tank. I just figured they moved around a little. /forums/images/graemlins/dunno.gif

 

[Eric M.]

Both gas tanks and pick ups are about 1 year or 3K miles old. Plus, I doubt both sides would go at the same time.

Yeah, my guage "waves" to me, I can watch the guage go from 1/2 tank to empty and back!

Eric M.

 

[dyeager535]

This is an interesting problem.

I just put a TBI sender in my truck, that I got from a tank with a broken baffle. Gauge worked when the other sender was in there, and I swapped gauges just for the heck of it (easy when there is no dash) and no change. New sender, gauge sometimes reads half full, sometimes over full. Connect new sender up (external of tank) gauge works.

Going over bumps, the gauge bounces all over the place, very rapidly. Even slow acceleration shows the problem.

I know the reading is "dampened" by something, (or all gauges would fluctuate wildly) but I'm not sure if it's the sender or the gauge. With my problem I suspect it is in the gauge, but there doesn't appear to be anything that would accomplish this in the sender.