How many here are currently, or in the past, have had problems with thier gas guages being erratic.

The guage in my '79 is very erratic. It seems like every morning, it greets me with a full tank, and by the time i get to school it says Im down to a half. I can fill the truck up, and it will drop down to dead empty.

Its kindof unsettling, driving around and not knowing how much gas I actually have. I was just wondering if anyone has had this problem, and how they cured it if they did...

Anyone that can help me gets a virtual cookie

 

Mine's out completely. It moves maybe 1/8 inch off empty when you turn the key on. I never really investigated it but I imagine it's the sending unit. I just use a notebook in the glovebox to keep track of when I should fill up. That's handy because I can keep track of my mileage that way too. Solving the problem isn't worth dropping the tank for me.

 

mine reads about an 1/8th of a tank off. but im not sure which way. i just keep it above a 1/4 of a tank and plan to replace the sending unit when i get the chance.

 

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It sounds as though your sending unit in the tank itself has issues. I actually opened mine up once and the little arm which rubs against the resistor windings literally fell off when I touched it. Make sure all of your grounds are clean and the wires to and from your connections are not corroded. This may entail peeling back a little of the wire insulation to confirm. Also, the voltage regulator on the back of your instrument panel can affect the way gauge reads. Troubleshooting the fuel gauge system in these old trucks requires patience and perseverance.

 

That's exactly how mine reads. But it's this way consistently, so I can trust it now that I know how to read it. Wonder what causes this?

 

Mine goes a 1/4 of a tank over the Full when I fill it and it goes down to about an 1/8 past the Empty sine when empty. I know how man miles on E or right above E I can go about 30 lol oh have I done this more than it is healthy for the truck. I guess mine isnt too bad becuase I just put gas in when I get towards E so mine isnt too bad but it is erratic as in i'll start it up and be on the road and half way down the road it goes from above a 1/4 a tank to inbetween the 1/4 and Empty so I put gas in, I dont want to experiment much unless I know. My back tank however doesnt it is very accurate, it doesnt go past the Full, nor does it go below Empty, empty is empty. I havent figured out that one, i would think if my midship tank was "erratic" my back tank would be too lol

 

First, let me say that both my tanks have been dropped, the screens replaced. Dumb me, I didn't replace the sending units when I did this, but on the main tank (rear) I am going to when I drop it again to replace the fill/vent hoses (already did this on the aux midship tank).
Main tank (rear) Seldom (though sometimes does) register full when it is full. Mostly when full it registers 3/4...then at about 1/2 it drops to 1/4 and stays there until suddenly it drops to almost empty. Then, if I have not been watching the odometer I panic

Aux tank (midship) "Usually" goes to full when full, but when 1/4 full never goes below that mark. Again, I have to watch the odometer.

Both are a pain. I am replacing both sending units!!!!! (and, if necessary, the voltage meter on the gauge)

Dak

 

I forget to mention that my sending unit is brand new. I replaced it already. Dropping the tank really isnt that much of hassle.. at least it wasn't for me.

At any rate, I guess now I can move up to the VR on the instrument panel. What all is required to get to that particular peice?

And also, Im pretty sure my instrument panel is supposed to light up when I turn the headlights on, but mind doesn't and there is a light that just hangs down behind my dash..

I cant figure out where it goes (top, bottom, back, side.. etc) in the panel, but im sure thats the light thats supposed to go in the instrument panel.

Can anyone help me with that problem?