Fuel filling problem

[Toastyyosty]

So I've just picked up a 73 challenger from an old friend of mine and got it running after a few years of sitting. I drove it back and forth to work a few times to work on a drive for fun but I recently had the vapor separator lines break while I was filling it up. Got it home and replaced the hoses and went to put some fuel in it but I can't put more then a couple gallons in it without it coming up the filler neck. The gauge says it's empty and the tank sounds empty. I haven't dropped it yet but I was wondering if there'd be any ideas out there that I could look into. Any and all help would be great!!

[brads70]

sounds like a vent line is blocked somehow?

[Toastyyosty]

Ya that's what I was thinking too. I know the previous owner took off the charcoal canister but I've read of a lot of people doing that with no problems to date. What other hoses would I look at?  I don't think there's a filler neck vent.  Just those 4 that go to the vapor canister.  Do you have a vacuum diagram that I'd be able to take a look at?

[burdar]

There is a valve inside the vapor separator.  It's probably rusted closed and isn't venting the tank.  Take the separator off and soak it in EvapoRust.  It will attack the rust but won't touch the surrounding metal.  That should free up the internal valve.

Once you have it removed, block three of the four nipples with your fingures.  Blow in and out on the vapor line nipple.  You should be able to hear and feel the valve moving inside.  If you can't, it's rusted solid.

As long as the vapor line wasn't plugged, removing the charcole canister shouldn't cause your problem.  You'd just be venting fuel vapors into the atmosphere instead of storing them to burn later. 

[Barracudadan]

There is a valve inside the vapor separator.  It's probably rusted closed and isn't venting the tank.  Take the separator off and soak it in EvapoRust.  It will attack the rust but won't touch the surrounding metal.  That should free up the internal valve.

Once you have it removed, block three of the four nipples with your fingures.  Blow in and out on the vapor line nipple.  You should be able to hear and feel the valve moving inside.  If you can't, it's rusted solid.

As long as the vapor line wasn't plugged, removing the charcole canister shouldn't cause your problem.  You'd just be venting fuel vapors into the atmosphere instead of storing them to burn later.

X2! Evaporust freed up my vapor separator that stuff works great!

[LAA66]

 Good information.

[Toastyyosty]

I'll defiantly have to try that! When I Replaced the four vapor hoses I took the canister and I herd something moving around but I haven't had any problems with it filling up until I messed with those things.... I might have gotten it stuck while I had it down and shook it haha. Thanks again for all the great responses!! I'm hoping I'll be able to get it out one of these nights and try that fix.

[burdar]

Those cracked hoses could have been venting the tank for you if the internal separator valve is stuck.  Replacing the bad hoses then sealed up the system...

[Toastyyosty]

So I just finished cleaning out the vapor separator and it's come up with the same problems. I'm still unable to put more then 2 gallons in the tank. Any other options?? I'm Gunna take the filler neck off tomorrow and see what the tank looks like.

[4Cruizn]

Well I'm looking forward to the solution to this one . . . .    Could something be in the tank?  Is the gas guage working?  My first thought was pressure building up in the tank but the more I think about it . . .     Do you live in a state where the gas nozzle has a air tight fit to the tank?   

[Toastyyosty]

Ya I'm starting to think its something in the tank but then again, if it is then wouldn't the motor hesitate when you drive it? The car runs well. Needs a carb but that's a separate issue.  I live in California which does have the vapor lock style gas nossels, but all this has started when the hoses to the vapor separator broke. I go to put a 5 gallon jug into the filler neck and once it's about halfway done filling you can see it start to come up the neck. The guage works. I've tested the voltage at both the sender and the dash. All ok. I started to think it'd be something in the lines but then I go back to the start, it wouldn't run well if it was. You hit the bottom of the tank and it sounds empty. No rattles like rust build up but then again. I'm starting to get clueless on the whole issue. It's such a simple set up compared to new cars now a days. Guess I'm not so good at simple anymore lol

[4Cruizn]

I would pull one of the hoses off the tank and see if it will take fuel then with a good vent.  You will know it is vented with the hose pulled off and if it takes fuel . . we know it is pressure that is causing the issue.  If you still have an issue  . . . 

[burdar]

I thought someone posted having problems filling the tank with California's fuel pumps.  They aren't designed for these old cars.

Make sure the four vent lines going into the tank are free from any obstruction too.  It doesn't matter if the vapor separatior is working if the vent lines on the tank are plugged.