Drastic proposal for gas smell. Will this work?

[Joe Papa Sr]

Many of you helped me with my 3yr old problem of gas smell, and I tried it all, and more, to no avail. No "buddies" near me here for "hands on help", so only thing left to do is , Im thinking, to give the fuel system a kinda vasectomy/appendectomy.

This is in hope of removing the possible cause of the smell, but if it doesnt work, easy to go back to the orig system.....

What if I disconnect the tube that leaves the gas tank going to the blk plastic vapor separator, and plug it up v well. This would eliminate that syatem with its convolutions/twists and myriad of fittings/components as a source. Then, drill a tiiiiiiiny pin hole in the gas cap, for venting to the EXTERIOR/outside.

Whats so wrong with that, considering my scenario? Its not like Im polluting, cuz the smell is polluting me already!!!

Comments, as always, from members are appreciated.

Joe Papa Sr

[Tifosi]

I think you'll regret going for a hole of any size in the gas cap regardless of what you do to the rest of the system truth be told.

I can say that with a bit of authority, because, well, I already tried it a couple years back....

If you think you've got a smell now, wait til you get the gas sloshing aorund in there and every bit of vapor comes out through that hole, and usually under pressure as things warm up. We're talking water your eyes level of stink.

However, if you were to find a cap that had a one-way valve built into it so that air could enter only and nothing could revert back out through the cap, you'd likely go a long way toward reconciling the problem in conjunction with bypassing the vapor seperator as you describe.

I ended up using one or other of the methods described in one of the threads, but cannot recall specifically which one other than it had a bit about putting a restrictor in the plastic intake tube that goes over the engine that deals with the vapor canistor.

The premise being (I believe anyway) that it forces more vapor to be pulled in under the heavier post throttle body plenum vacuum than the pre-throttle body bigger bore hose, so in turn the vapors get sucked out more effectively and thus less stink. (I 'think' it was a Greg Gordon solution if you want to look by username)

The rest of the system stays intact other than making sure the one way valve works and, IIRC, the removal of the metal check valve that prevents fuel from coming back up the pipe in the event of a rollover. (unless of course the one you have works perfectly well, in which case it's ok to leave in place)

All I can offer beyond that is to say again: don't drill a hole in your gas cap.

If you were here I could give you a demonstration as I'm still using my modified cap with a cardboard gasket to block off the hole and it would take about 5 seconds to pop it out and go for a drive around so you could smell the difference.

[Tifosi]

See hose #6 in this schematic.

The restrictor is placed at the end where it connects to the plastic manifold bit.


I did a bit of searching, but I'll be damned if I can find the specific thread that described it. All I know is that it definitely worked.

[Tifosi]

Just had a flash of insight:

To give you an idea what a drilled cap might be like, drive around for a couple days with no gas cap at all.

The trunk may not stink as much but I think you'll find the general reek level while driving goes way up.

[bianchi1]

.. here's an idea, no one thought about... just relocate all the vapor recovery parts,and hoses underneath the car..yes a little bother, but there is a lot of room behind the spare tyre well..no hoses in the trunk..no fumes cool idea , yes??

[Joe Papa Sr]

OK, I was hesitant to drill, also ruining my "original " car, but I will try this AM removing the cap entirely, just for my drive into work.

But, I dont se how, though, you would get more smell while driving this way, as the direction of the car wil be opposite to the air as you go forward, see what I mean?

On that metal one way valve near the vapor recovery tank(blk plastic), how can I tell if it works well, I mean, Ive taken it off, blew in it, and it works, but it doesnt "open" unless you put in quite a bbit of pressure(with your own mouth). What if it is designed to work efficiently at a specific min/max pressure, for which I know of no spec on this, and none in shop manual? Otherwise, Id remove it, and take my negligible chance I dont roll over.

[Joe Papa Sr]

Quote:

Originally Posted by bianchi1 .. here's an idea, no one thought about... just relocate all the vapor recovery parts,and hoses underneath the car..yes a little bother, but there is a lot of room behind the spare tyre well..no hoses in the trunk..no fumes cool idea , yes??

[Joe Papa Sr]

Quote:

Originally Posted by Tifosi I ended up using one or other of the methods described in one of the threads, but cannot recall specifically which one other than it had a bit about putting a restrictor in the plastic intake tube that goes over the engine that deals with the vapor canistor. The premise being (I believe anyway) that it forces more vapor to be pulled in under the heavier post throttle body plenum vacuum than the pre-throttle body bigger bore hose, so in turn the vapors get sucked out more effectively and thus less stink. (I 'think' it was a Greg Gordon solution if you want to look by username)

[Joe Papa Sr]

Going in this direction, the problem may wel be with the charcoal canister, I dunno, but Ive taken apart everything else, so maybe Ill yank the pass tire, drill out the rivets on that panel in wheel well, take out the canister, and then......what??(wondering, as there is little one can do to a canister, cant even buy a new one, cripe).......

[ghnl]

I think it'd try some irreversible things before drilling the gas cap. You could disconnect everything that has to do with the vapor recovery system (block off the hoses at the intake - hoses #6 & #13 in the sketch above) and see if that makes any difference. If it does NOT, then you'd know the problem ain't with that system.

1. The one way valve should 'work' at quite a low pressure. I don't know the PSI but it shouldn't needed a real blow-hard to make it work. You can squirt some carb cleaner spray into it and shake it about to help clear out any gunk.

2. There should be some phillips head screws, not rivets, securing the access panel in the wheel well.

[Tifosi]

Quote:

Originally Posted by ghnl one way valve should 'work' at quite a low pressure.

[Joe Papa Sr]

Quote:

Originally Posted by ghnl I think it'd try some irreversible things before drilling the gas cap. You could disconnect everything that has to do with the vapor recovery system (block off the hoses at the intake - hoses #6 & #13 in the sketch above) and see if that makes any difference. If it does NOT, then you'd know the problem ain't with that system. Eric, Ill plug up hoses 6&13, and as far as in the trunk, just plug up any one of those little hoses around/going to the vapor tank? 1. The one way valve should 'work' at quite a low pressure. I don't know the PSI but it shouldn't needed a real blow-hard to make it work. You can squirt some carb cleaner spray into it and shake it about to help clear out any gunk. Geez, mine takes an AWFUL lot of "blowing" pressure to activate valve, AND it has been solventified in the past. Maybe Thats my problem, huh?? Im tellin ya, ya gotta blow real hard for that valve to open through!! What do you think?? 2. There should be some phillips head screws, not rivets, securing the access panel in the wheel well.

[Joe Papa Sr]

Quote:

Originally Posted by Tifosi I agree. Mine can almost be operated by simply shaking the thing. Grams of spring pressure, not kilos. VERY light tension that provides just enough to move the check ball into position should the evil happen. (sometime it helps to try and orientate the whole valve so the ball is in the retracted position) As it's an all metal thingy, you can get away with flushing and soaking with some of the more agressive cleaning agents like carb cleaner or even brake cleaner sprays. Soaking wouldn't hurt a bit either so you can kinda work the ball back and forth with a pipe cleaner or something pushed down through the seat end. Correct. Im tellin you Tif, This is a revelation. My valve is nothing like that...toooooooo hard to blow into, and requires Kilos! When I remove, and shake, I noticed it too rattles, not sure what that means, as I posted above, this may be my problem. Thing is, they done sell new, so I must just remove, and block off tube, so no leaks if I roll over..... Ever had the old ladies hair (or yours if you're a hippy like me) blow around into her face while driving with the top down? Flick a cigarette but up and out only to find it jumped right back into the cabin behind the seat or in the cargo area? Both end up moving opposite to the direction of travel too because of the aerodynamics causing curls and reversions in the airflow over and around the car. (it's just that the bugs hit harder from the front, but they can still slap you in the back of the head now and again ) If the air can do that to heavier than air objects like butts, hair and hats, it can certainly do it with lighter than air fuel vapors.

[Elio Comello]

OK Joe, getting back to scientific approach...
You suspect pressure buildup and escaping vapours from this pressure as the cause of gas smell.

I would try to put (tee in) a low level pressure gage in the vapour line, that would give you a measurement of what pressure you have. I have a magnehelix low pressure gage that measures pressure or vacuum in inches of water.

I was going to suggest using the gauge our ancestor Torricelli invented for vacuum or a mercury manumeter, but Hg is pretty messy stuff especially if you are driving around.

Ciao compare giuseppe! it was 75 degrees here (finally!)

TTFN Elio