charcoal canister wet with gas

[hooD]

After I reconnected the 3 hoses going to the charcoal canister and going for a nice cruise, I start smelling raw gas under the hood.  I traced it to the bottom of the charcoal canister.  When I say that I reconnected the hoses, I should say that I put the Fuel Tank hose back on to the canister.  With that said I'm now getting raw gas coming up to the canister.  I had plugged that hose up many years back and that was for the same reason back then.

   Why is it pulling fuel from the tank up to the canister? 

3 canister hoses:
-purge
-fuel tank
-carb bowl

for 2 cents I'd like to ditch the canister but what would I be compromising?

[Chryco Psycho]

Lack of vent in the system so it is pushing pressure out through the CC

[Aracer]

Just run a hose from the tank tube up under the intake. The heat and wind will clear any fumes.
I never smell any gas like when you over fill and park on a hill downward at the canister bottom. Or you could run it to the vent on the oil breather that some older cars had.

[Bullitt-]

There is some kind of valve built into the manifold/vapor separator the 4-lines from the tank connect to,   I'm guessing there may be a problem there but don't have a solution.   
  I've envisioned a brake bleeder device I have as working to let air into the tank but not letting fuel out. Paid less than 10-bucks at a local parts store....good 1-man bleeder


 

http://www.amazon.com/K-D-Tools-2538-Brake-Bleeder/dp/B000CO9NXY
   

[ShelbyDogg]

First of all, make sure that the hose attached at the rear expansion tube is the tallest of all of the tubes. Do Cudas have the tall tube in the trunk like my Challengers have? Your hose might be sucking fuel if hooked to the wrong tube. It should be sucking vapor only unless you overfilled and the expansion tank filled vith gas.

Did you fill your tank to the top before taking your cruise?

If your Charcoal canister is bad, you can cut it open and dump all of the bad charcoal. Go to your local pet store and buy a bag of charcoal to replace it, then glue your canister back together. No more gas vapor smell.

But you have to fix your problem of getting liquid into the hose from the tank first.

[Aracer]

It's a good idea to replace the 5 hoses on the vapor separator found on 1974 and older cudas. The heat under there will cause cracking along the clamps.

[shadango]

I yanked the CC when I first got the car......on the steel line that is left in thelower passnger side of the engine bay I just stuck a small breather on it, connected to it by a short stub of hose.

I just replaced my fuel cap (and the filler neck to allow it) with one that seals and is unvented and so far so good....no major gas smell under the hood like I had feared......

[burdar]

I don't know if it will help at all but, remove the vapor separator from the shock Xmember.  Blow in and out on the tube that connects to the vapor line.  You should here a valve open and close.  It only lets air by the valve in the middle of its travel.  Meaning you suck on the hose and it pulls the flapper open...you get a little air flow...and then the flapper closes again.  Same thing happens when you blow on the hose.

Make sure that this valve is working properly.  Mine was all rusted up.  I soaked mine in EvapoRust and got it working again. 

If all else fails, you could add a vented gas cap.  I assume the 70 Cudas were the same as Challengers as in that they used a vented cap.     All other years used a sealed cap.

[hooD]

If all else fails, you could add a vented gas cap.  I assume the 70 Cudas were the same as Challengers as in that they used a vented cap.     All other years used a sealed cap.

My gas cap is a sealed cap.  I opened the cap yesterday and could hear the pressure bleed off.  Twelve hours later I opened the cap again and let a tad more pressure out.  So, maybe I need a vented cap.  Who sells them?

[Bullitt-]

Stant gives part# 10623 for a '70 B'cuda......  Advance Auto carries $5.19
   They do not list a standard cap for a '73 but the locking cap is a different #, I believe  vented/sealed is the difference.
Stant-BP Fuel Cap
Part No. 11623    Warranty    
W/O Calif. Emission System; OE Type Fuel Cap; Carded
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Fuel-Cap-Stant-BP_6091075-P_112_R|GRPCAPSAMS_1309163648___

[hooD]

Well, I figured out why: (1) gas was being sucked up to the charcoal canister and (2) why there was pressure constantly on the gas tank.

Fuel tanks from 1973 had 4 vent lines going to the vapor separator.  I had replaced my fuel tank back in 1982.  It was from a 1970 Cuda which had only one vent line. 

Some how I had connected the vent line from the 1970 tank to the line that goes to the charcoal canister, totally by-passing the vapor separator.   After reading some posts and looking at the diagram in the service manual, I decided to crawl under the car and see what was what.

I saw my blunder from 1982 and had to laugh.  I fixed this by putting the vent line from the tank to my 4 line separator, plugged the other 3 open tubes on the separator and made sure the correct line went to charcoal canister from the top of the separator.

There is no more hissing of pressure when opening the gas cap and the charcoal canister is not sucking raw fuel any longer.  It only took me 28 years to figure this out.  But I couldn't have done it without everyone's help.  Thanks to all!

By the way, my gas cap is OK and I do not need to get a new one.  In case anyone wanted to know I paid $15 at the junk yard for that tank in '82.

[burdar]

Better late than never.....

Glad you figured it out.

[Bullitt-]

Can't say I saw that one.....Great that you were able to resolve. 

[hooD]

Can't say I saw that one.....Great that you were able to resolve.

Now all I need to do is to get the doggone fuel gauge to work right.  How much gas can I leave in the tank when I pull the sending unit out?  Half a tank maybe??

[Strawdawg]

Now all I need to do is to get the doggone fuel gauge to work right.  How much gas can I leave in the tank when I pull the sending unit out?  Half a tank maybe??

If you look at the tank, you will see the sending unit goes in to the side a bit above the seam of the two tank halves.  Therefore, a half of tank of gas, or less, will be fine.

Based upon my own experience and all the threads on the subject here, I would take the new sender and connect it to the gas gauge wire and a ground and move the float up and down to see where the gauge reads....before sticking it into the tank.  Then you can bend the float arm, if required, to adjust to give you the gauge reading you desire before you finish the install and find it may read empty when the tank is still half full.