I filled up the Bronco this morning after going down to about 1/8 of a tank. I filled it all the way up with some nice 93 octane as a "treat" for the Bronc because I've been doing a lot of commuting lately. I filled the tank all the way up and then topped it off, like normal. When I got in the gauge was only at halfway. I turned it off and back on and it was the same. So I drove some ways and it still did not go up. I stopped and tried to put some more gas in and it took about 1/2 a gallon and was coming back out of the filler pipe so I know that it is full.

I have never had any problems in the past, except if I let it get VERY low, like 1/16 of a tank, the needle would bounce all over until I put some gas in. But that only happened once or twice, now I just keep gas in it so that doesn't happen and it has not happened in over a year.

Maybe I put too much gas in, and the gauge will go "up" as the gas goes "down?" I hope so. If it is the sender, then it's gonna stay the sender because I am not dropping the tank or cutting holes in the floor for that. If it is the gauge, I have a couple of spare gauge sets that I pulled from boneyard trucks that I need to swap out anyway, for the alt gauge and the oil pressure gauge.

But I am hoping that maybe I just overfilled it somehow, although I did not do anything different from any other time that I filled it up. I always top it off even though I know that you are not supposed to, but it's never caused a problem (on some newer vehicles it will make the check engine light come on). Hopefully it will fix itself. Has this happened to anybody here, and what happened?

 

It could be the gauge is just stuck. Sometimes a good tap will fix it or the gauge is going bad. I have also seen this if you ignition switch it turned too far forward; I know this is weird but it has happened to me accouple of times in my '86.

 

I had the same issue and it was the float. Unfortunately, it still means you have to drop the tank to replace it. Should you go there, then just replace the sender too.

 

I don't think that the gauge is stuck, because I can still see it "floating" up and down a little bit on braking or accelerating. I did try rapping on the gas tank a little bit at the gas station with the windshield squeegee with no luck. I welcome more comments, especially about having it happen right after a fillup. It's a bummer to put in $56+ worth of fuel and not even get the joy of seeing the gauge all the way on the right (sometimes we have to take our simple pleasures where we can get them!).

 

If you do decide to go for the tank fix, it really isn't that bad. With the hieght of our Broncos, it is easy to get up under there and remove the bolts. Just spray the hell out of the tank shield bolts with PB Blaster to help them come out easier. Use a floor jack to lower it and of course use a floor jack to support it and lower it out.

 

Have you tried tapping your dash? Give it that loving tap, just enough to know you mean buisness.

I also agree with BillyBob that it could also be your sending unit. Double check the wiring going to the sending unit. You should be able to pull the plus ogg without droping the tank and use a volt meter to see if it is getting a full charge. Maybe hookup a 9 volt battery to the wire to see if the gauge goes all the to full.

Hope this helps.

 

I drove 25 miles or so to work today, I was hoping that as the fuel went down, the gauge would go back to normal. So far it is still around the halfway point, but it definitely does move because it floats back and forth as I accelerate or stop. Maybe when it gets down to the "real" half a tank, the gauge will start working again.

 

Is that the best way to test these gauges when off of the truck? I have two full sets of factory gauges that I would like to test, that I got at the boneyard. What is the best way to test them without installing them in the truck?

 

you don't need that much of a charge going to the gauges to see if they work.

 

The problem fixed itself. The gauge seemed to be a little "looser" on my way to work last night, and when I left work this morning at 6AM and started the truck, the gauge went up to where it should be and has continued to work properly since. I had a feeling that it would eventually fix itself. I also parked it on an incline during the day when I was off, parked in the direction that makes the gauge go up. That probably helped too.

I think that my topping off (ie. overfilling) caused the problem. From now on I am just going to fill it until the gas pump shuts off automatically and that's it. These gauges don't seem to like going to extremes - if it gets too low, like 1/16 of a tank, it bounces around like a mad idiot until I put some gas in.

Thanks for the help - I am going to use the battery trick to test the gauges that I got from the boneyard.

 

OK on the way to work today the gauge kept fluctuating between about half and where it should be. Back and forth, slowly. So I don't know, that doesn't seem like a float or sender issue. to be fluctuating like that.

 

It seems to be OK now, I have driven to work and back twice now and it does not fluctuate anymore. I think that it was the gauge itself causing the problem, because of the fluctuation. If the float was stuck then it would not move. I have a couple of spare gauges to swap in if I need to.