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Tue Aug 05, 2003 1:36 pm

I found this thread to be of Great use, so I carried it over:
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Gas Fumes!!?? C.Kometz originally said... (4/15/2003 at 9:28AM PST)

I have a '73 Super project car, which is now my daily driver. I find that, after a few minutes of driving, I get a fairly strong smell of gas inside the car, but can't figure out why...
aircooled_mechanic said... (4/15/2003 at 9:42AM PST)

First check all of the fuel lines in the engine compartment. Make sure they all have clamps on them and are in good condition. Second, check to make sure the carb and fuel pump are bolted on tightly and that there isn't gas leaking from them. If your carb is leaking gas it will be obvious. Also, check to make sure all the vent hoses are in good shape and connected in the trunk. Alot of people disconnect all these hoses and the hose to the charcoal canister under the passenger side rear fender. Even if the fuel vent hoses look to be in good shape (in the trunk) smell them. IF they smell like gas, replace them.
C.Kometz said... (4/15/2003 at 9:46AM PST)

Charcoal canister? There isn't one on mine. Maybe the previous owner took it off. Do I need this?
1972_1302 said... (4/17/2003 at 4:45PM PST)

Check the fuel filler hose, the gasket around the tank sending unit and all the vent hoses in the trunk.
Aussiebug said... (4/20/2003 at 8:32AM PST)

Most 73 cars would originally have had the charcaol canister, but if it's been removed, there is a right and wrong way to rearrange the fuel venting.

You might find an expansion tank (with 4 vent connections) above the fuel tank, or that might be gone too now. IN any case, with the system below, it's not used.

Have a look at the fuel tank. There should be a small vent line in the right rear corner, and some tanks have them in the left rear corner too. All these should be connected together and then connected to the main breather pipe next to the filler neck (which allows the fumes in the tank to escape whilst filling), but use a T junction close to the large breather pipe so you can now run the actual vent line up and over the instrument cluster (making it the high point in the system) and down the left side of the fuel tank and out under the car from there (there may be a slot in the body just below the left side of the tank). Never use a vented gas cap, and never run a short vent line straight down the right side - these will always cause fuel smells, expecially in left turns.

At the back, in the engine bay, the hole the fan shroud (right side) should be blocked off and the hole in the air cleaner blocked off - these were part of the charcoal canister venting system.

Check all sections of rubber fuel line - under the tank (you have to remove the tank in a superbug to see it), over the gearbox and both sides of the fuel pump - use the corect cotton covered VW fuel line - NOT the 5/16" common size - it's too large and won't clamp easily.

And as aircooled... said, make sure none of the fuel lines in the engine bay are leaking, especially where the brass carby inlet sits in the top of the carby - that can come loose after 30 years of fuel lines vibrating on it - there's an easy permanent fix if this happens (email me aussiebug1970 at yahoo dot com).

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/
C.Kometz said... (4/20/2003 at 5:39PM PST)

Thank you so much! I appreciate the help greatly... I will do all of this tomorrow.

Chris
72bug said... (4/22/2003 at 10:52AM PST)

Here is a link to buy a vapor canister.. Yes they still make them. maybe a little bit different but should work..

http://www.btlmex.com/product.asp?3=202

OR you could follow the direction below to not use the system at all..

http://www.superbeetlesonly.com/vapor/vapor.html
Superman said... (5/5/2003 at 6:21AM PST)

I didn't know the canister was available. I'll have to update my article to include that info.
aircooled_mechanic said... (5/5/2003 at 9:43AM PST)

Wouldn't removing the ventilation system on the fuel tank be a bit dangerous? Especially in a hot climate? KABOOM
Superman said... (5/5/2003 at 9:53AM PST)

Drove mine like this in southern Louisiana for 2 years (with the aircooled motor) and nothing bad ever happened, also a 22 year experienced Volkswagen Master Tech (my father) approved my doing this to my car. Please take note of the use of a Jetta vented gas cap. I do agree that a completely sealed tank/fuel system would be a bad thing.

I still have it like this to this day but now have a 90 psi fuel pump (I have a Golf GTI motor with CIS).

However, as my article states, "do what is in your best interest". There is an active thread on my forums about this topic.

http://www.superbeetlesonly.com/forums
74SuperDriver said... (5/5/2003 at 2:11PM PST)

So, which mthod is better? Robs or Supermans?

Thanks,
Matt
aircooled_mechanic said... (5/5/2003 at 2:32PM PST)

I would buy a Bentley Manual, and do it like the manual says. Mine is stock and works great. I'm sure a venting gas cap works, however, unlike a watercooled car, the gas tank in an aircooled car is up front. So wouldn't the tank fumes, just vent into the passenger compartment? Wouldn't it be especially bad if you have an older bug with the gas cap inside the trunk? Where do you think the gas fumes are going to vent? I still say leave it stock. Let the fumes vent out the back of the car, away from the passenger compartment. Charcoal canisters can be found in junkyards for almost nothing. Or buy one from Btlmx. 58 bucks and you never have to worry about it again.
Superman said... (5/5/2003 at 2:44PM PST)

I would say stock is best, the method I posted was just a ghetto fix but now that the canister is available again there isn't a reason not to fix it right.

Good point about the gas cap being up front but I never smelt anything nor did any passengers complain or maybe they were high from the fumes LOL!

This topic is has been well discussed on my forum:

http://www.superbeetlesonly.com/cgi-bin/iB3/ikonboard.cgi?act=ST;f=13;t=149
74SuperDriver said... (5/5/2003 at 5:15PM PST)

How about the Plastic Vapor separator? Does anyone have a source for that?

Thanks,
Matt
aircooled_mechanic said... (5/5/2003 at 5:38PM PST)

If you are refering to the plastic part in the trunk in which the vent hoses from the tank "plug" into, you can get them at a junkyard. I am parting out a 1973 Superbeetle and have one I would sell for cheap.
Aussiebug said... (5/5/2003 at 9:10PM PST)

aircooled_mechanic said... (5/5/2003 at 9:43AM PST)

>Wouldn't removing the ventilation system on the fuel tank be a bit dangerous? Especially in a hot climate? KABOOM

My method doesn't remove the ventilation system - it reverts it to as close to the non-emissions venting as is possible.

If the charcoal canister can be obtained, I'd use the stock system. But where parts have been removed or damaged by POs, my method will provide a system which works without the charcoal canister or expansion tank up front being used.

And re the vented gas cap - most bugs using a vented cap will get gas smells in left turns - the bug filler is only about 2 inches above the tank and so the back of the gas cap WILL get fuel splashed in turns. VW didn't used vented gas caps in bugs for this reason.

And re Aircooled's comment "Let the fumes vent out the back of the car, away from the passenger compartment." (not critising - just educating) With the charcoal filter system properly installed the tank venting is actually provided from the fan shroud - the pipe there connects to the charcoal filter to drive unburned hyrocarbons through the vent to the air cleaner (and into the engine where they are burned) and the tanks gets vented from the same fan shroud line via the long vent up to the tank in front. So there are no fumes venting out the back of the car - they are held by the charcoal filter and when the engine is started they are driven (by the fan) into the carby.

Incidentally, the reason that these cars have an "expansion tank" up front near the fuel tank is that charcoal canisters can not be contaminated by liquids, so the "expansion tank" is actually a vapour separator so no liquids get down the low lying main vent to the charcoal canister at the rear of the car.

Rob
Rob and Dave's aircooled VW pages
Repairs and maintenance for the home mechanic
http://www.geocities.com/aussiebug1970/
Superman said... (5/5/2003 at 9:28PM PST)

Well said Rob, and as for my setup, I drove it like that for 2 years with no smells, no leaks, no problems. Maybe I was just lucky. The gas cap I used was the "PreVent" by Stant.

Tue Aug 05, 2003 3:23 pm

Thanks!

...and still the best thing to do is have the entire original vent system intact and properly functioning (if that is at all possible).

Tue Aug 05, 2003 6:43 pm

Hi Superman!
That is what I am doing, One hose at a time...
I am not looking forward to the two under the dash at the top, drivers side of the tank!

Tue Aug 19, 2003 11:11 am

Hooray!! The smell was getting really bad; I was picturing gas dribbling all over the place.

I've read the articals available and considered the solutions. I decided I wanted the system to operate as close to proper as possible. I used 3/16" fuel hose and little hose clamps. It took about 1/2 an hour and only cost $15 in parts. No gas smell!!

Things that aren't right:
1) No charcoal cannister. I'm not particularly concerned with the damage to the environment caused by fuel vapors coming out of a 4mm hose. One word: Exxon

2) I used 5/8" heater hose for the filler neck vent. I'm not real crazy about it; it's not rated for gasoline. I'll keep an eye on it and look for 5/8" fuel hose. Maybe a marine dealer or Mack truck shop might have something.

Wed Aug 20, 2003 7:10 pm

often overlooked is the gas cap gasket and the collar around the fuel filler pipe. These sometimes contribute to the gas smeel problem.

Thu Aug 21, 2003 5:38 pm

Even the cap itself can be the problem, i just purchaced a 72 super and would notice a gas smell all the time, after driving a day i noticed it was even worse when i took hard lefts. the check ball in the cap had broke loos and every time i turned gas would get through the cap, it was a 8 dollar fix from NAPA

Thu Aug 21, 2003 7:32 pm

I replaced my gas cap after I noticed the gas running down the side of the car! :shock: