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Fuel (gasoline) odors and vapors inside the car and in the trunk.


Racer-X-

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Back seat passengers (the ones that pay the bills on this project) have been complaining of fuel odors.  So I've been working on the fuel system at the rear.

 

One thing I've noticed is, the tank we have (I think it's a reproduction or aftermarket tank) has a vent fitting on top, and there's a hose from that fitting to a metal (aluminum?) "remote vent fitting" which looks suspiciously like the Holley 19-174 unit.  That hose and vent is tied to the fuel filler neck with a zip tie.

 

I see a couple of issues with this.   During refueling at the gas station, the fumes/vapors from the tank are going to go out the vent and collect under the car in the rear fender area.  They could be drawn into the car depending on airflow when the car starts driving again.  Also, when the thing is parked in hot weather, and the fuel in the tank expands, those vapors/fumes are released into that rear fender area, and again might be making their way into the rear cabin when the car starts driving again. According to the drivers, the problem seems to be the worst when they start driving after it's been parked, so this is consistent with my theories.

 

Here's my proposed solution.  I'm looking for any advice or suggestions for changes.

 

I plan to weld or braze a pipe onto the filler neck pipe, up near the cap, and fit an appropriate hose barb there to run the hose from the vent fitting on the top of the tank up to the filler neck.  That should allow the vapor recovery systems at the gas stations to capture the vapors that vent from the tank during refueling. The down side to that is the cap is sealed, and there will be no vent to let air in as fuel is consumed, nor to let air/pressure out if it's parked in a hot location and the fuel in the tank expands.

 

To solve those two issues, I plan to install a tee fitting in the hose, and run from that tee fitting to a charcoal canister. I plan to move the vent fitting I have to the vent port on the charcoal canister.  That way, any vapors out of the tank will go through the activated charcoal filter in the canister, and hopefully the air that vents will not have a strong fuel odor.  And as fuel is consumed, the air will be screened by the vent fitting and filtered in the activated charcoal filter in the canister.

 

The canister I have is a 1990's Mopar canister.  It's part number 4601673.  I got mine from a 1994 Caravan, but many Mopars from the early 1990s used this unit.  One nice thing is that the bottom unscrews, and the activated charcoal filter inside is replacable. Rock Auto has the filter elements for under $2.

 

Does anyone have any suggestions or advice about this?  

 

Has anyone else had issues with fuel smells inside their car?

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The original tanks on these cars had a vented filler cap. The tank itself was not vented. Any fumes would be released by the filler cap on the outside of the car.  I'm not sure if you could arrange yours like that ie: close off the vent on top of the tank and fit a vented cap on the filler tube.  I suppose it would depend on how the filler tube is attached to the tank.  The original tanks had the tubes attached on top so that there are no pockets to trap fumes.

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2 hours ago, Racer-X- said:

Here's my proposed solution.  I'm looking for any advice or suggestions for changes.

 

Your solution is far more complicated than necessary. As stated above, the tanks originally weren't vented, just the caps. If you can't find a vented cap, plug the existing tank vent and drill a 1/8" hole in the filler tube just under the edge of the cap. This will vent the tank and keep fumes outside the car. (Please excuse the upside-down photo...)

 

gas-cap-2.thumb.jpg.8eb4e8c048384c8b25bfde0902a5d197.jpg

Edited by Sam Buchanan
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I have a 39 Desoto and these systems only vent tru the cap. I did a search on ebay and there are several caps for the your desoto.

 

refer to the title of the cap:  1929-1954 Chrysler, DeSoto Gas Cap | Stainless Steel   12.50 and this includes shipping

 

 

Rich Hartung

Desoto1939@aol.com

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This isn't an original tank.  It's a "for fuel injection" type reproduction/adaptation.  The filler neck into the tank isn't completely at the top. In addition to the vent fitting on top, it has two openings on top, one for a FITech pump assembly, and one for a gauge sender.  The cap looks fairly new as well, and seems to be a sealed type.

 

I guess I could still just run the vent hose to a fitting installed on the filler neck and use a vented (or make a vented) cap.  

 

Of course, I do have the charcoal canister already available.  Hose is pretty cheap.  The only thing I'd need is a bracket (easy enough to make). And I wouldn't have to worry about gas smells near the back corner on a hot day from fumes venting out of the tank that way.  I really need to completely eliminate any chance of fuel odors, whatever I do.

 

Thanks for all the input.

Edited by Racer-X-
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2 hours ago, Racer-X- said:

 

 

I guess I could still just run the vent hose to a fitting installed on the filler neck and use a vented (or make a vented) cap.  

 

If you have a vented cap you can plug the vent hose (or the fitting on the tank), the tank will vent through the cap.

Edited by Sam Buchanan
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