My fuel gauge is a little out of wack.. it is stuck on full. I went under and discovered the ground was all messed up so my father and i cut the wire re-sotterd it and attached it back to its repective area in hopes of solving that problem....

ANY WAY....i drive the car when i can and it deff. is using up gas because it obvioulsy needs it to run lol...but when i go to fill her up, she wont take more the 5 gallons of fuel before overflowing:confused:

Now my dad was driving it a while back and actually ran out on the road, so he filled it up. So its been empty before.. but i just dont understand why it wont take more then 5 gallons? arent these 20 gallon tanks? unless the censor isint broke and it reallly is full lol any ideas?

check the filler hose to make sure it isn't crimped, it could be taking gas but at a much slower rate and when that fills the air in the tank is pushing it back out. i betting on crimped filler hose or some other obstruction in the filler or vent tube. if you fill very slowly, can you get more than 5 gallons?

when the 05 mustangs came out, the vent hose is in an area where it can get crimped, and would shut off about every gallon, drove me nuts....

On my 1970 El Camino I had a similar problem. What I think might have been happening was that because my tank didnt have any vent or anything on it, that an air pocket or bubble built up at the base of the filler neck and stopping fuel from entering the tank. Not sur eif thats possible or if thats exactly what it was. For a while, I would pnly insert the gas punp nozzle part way in and just fill it up slowly. After a little while I loosened off the bolt holding up the passenger side of the tank and added a longer bolt with a locking washer on the end so it couldnt come right out. This sloped my tank slightly towards the passenger side and it fixed the problem.

That worked for my 70 El Camino, mainly I think because it had a driver's side mounted filler neck, if your Chevelle has a different filler neck then I don't know, may be able to try the same thing, if not, sorry I can't be of any more help.

Steve, the car gets filled up from the back, the license plate folds down and i fill it up from there..

Where is the vent hose located? I suspect this may be the problem (the air bubble)

Matt,
On my '66 the vent comes out of the top of the tank, enters the trunk, does a 180 and doubles back and exits under the car. I'm not sure your 68 is the same.

I gave the trunk a look, couldnt really find anything... is your vent hose out in the open or ?? Then again the 68's might not even have it in the trunk....anyone know for sure?

On the 69s the vents are on the upper front of the tank on the passenger side of the car. 68s should be about the same.

If you are not doing any freeway driving, drive the car until it runs out. Carry a can of gas in the trunk so you can make it to a gas station. If it only takes 5 gallons when you know it is empty, then you have an issue. If it takes 22 gallons then you know things are fine.