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Discussion Starter · #1 ·
this original tank is vented thru a tube in the wheel well area and the gas cap is non vented. my shop is always smelling of gas fumes. i was wondering if anyone had converted this type of fuel system to a closed system type with a return line back to the tank from the fuel pump.
 

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That's not your problem. Look at other places. Like fuel lines, your original tank and carb
 

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Discussion Starter · #3 ·
new tank, checked all fuel line and fittings front to back, and also o ring at tank line fitting. its coming from the tank vent in the wheel well as the closer you get the ps rear fender the stronger it gets.
 

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Discussion Starter · #4 ·
seems i read some where that a 90's B body tank would fit. Was looking for info on this kind of a swap. Been living with this problem for for 10 years.
 

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I have a 66 GTO, also uses non-vented cap. Vent line is 1/4" tube in the filler plate. This connects via a rubber line to a metal loop inside the trunk, behind the trunk lock bracing. Never any smell.
 

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On my 69 Elco I went through 4 Spectra tanks, all leak.. The latest one was for a 72 and has the 3 vent tubes.. I capped 2 and put a fuel filter on the third with a non vented cap.. It's so much better!! It only leaks when I fill up to the top..

Defiantly run a 1/4" return line with todays fuel...
 

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Discussion Starter · #8 ·
Thanks for the reply so. Was just able to get back to my car and check one more time for leaks from the fuel pump to the tank. There are none.

I read the links posted about positive pressure. Is this pressure being relived thru the vent tube and that's what I'm smelling. The Temps here in coastal NC are 80 one day and freezing the next.

Also, I am not running a pcv valve. I have a breather on each valve cover.

Also, if I don't crank the car for 4 or 5 days, it takes a lot of cranking to start it. Otherwise, it starts right up.

I have no engine issues, the car runs very very strong. Would any of the factors above create this annoying problem?
 

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1966 Chevelle SS396
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I may have missed it - but - did you blow out the vent line to make sure it's not blocked?

Something's wrong here, and, as usual, it's probably something dead simple and obvious.

As primitive and kinda oddball as it is, this system worked and still works if it is routed and plumbed as designed.
 

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I can speak for simple and overlooked on this very matter. I opened the cap today and had a ton of pressure, made no sense. Then I looked closer and when I installed vent tube, I left the cap on the open end knowing it would be a bit before I was putting fuel in it. Needless to say I forgot all about it and when I saw it today...:clonk:
 

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Discussion Starter · #11 ·
I never have any pressure release when I open the cap so I don't think the vent is stopped up but I will check and post pictures of vent tube routing.
 

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I never have any pressure release when I open the cap so I don't think the vent is stopped up but I will check and post pictures of vent tube routing.
yes, if you have fumes I doubt it is plugged. I was using more as an example of how simple things overlooked can create issues.
 

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66 Chevelle SS396 & 66 Chevelle 327 Convertible.
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I have had my 66 since 2004. Always garaged with a full tank during the winter and also garaged during the summer months. Never any smell of gas. Original tank, vent tube, and gas line. The only thing I replaced was the hose connecting the tank to the vent line and hose to fuel line. Non-vented cap. Maybe there is a hole up high in the gas tank? Its got to be the tank, cap, fuel line, vent line, rubber hose to ventilate or hose to fuel pump or full pump. Maybe you should isolate the fuel line at the tank and see if the smell persists after you fill the tank. If it does, then isolated the vent line. If it still persists its probably your tank. Good luck.
 

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Discussion Starter · #14 ·
the tank is new, same problem with original tank except o ring seat was damaged and yes it did leak. Thought I had solved the problem. I've been from carb to tank many times. no leaks. Here is a pic of vent tube. Routed as describe on the one with no fumes. The tube exits into the wheel well area and is open.
 

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Exactly same type as in my car as I pointed out in my above Post # 7
and this other Thread mentioned with pics
http://www.chevelles.com/forums/14-troubleshooting/929658-gas-tank-pressure-3.html
see Post # 32
" Gas Cap is a Non-Vented one
and I Fill my old Gas Tank up to the Top/Full/Neck Filler Tube every time I go Racing
Never ever smell of gas or spillage when I fill it up and park it in the Garage either
Here are some Pics of what is in my car on the Passengerside of the Trunk "

There must be something else leaking some where .
 
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