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Discussion Starter · #1 ·
Who passed gas?


What is the correct gas cap for a 72 with the emissions control canister removed? Vent or no vent? My car smells like gas inside and out when I drive it. Most noticable right after hard acceleration.

Ug, it makes me nauseous when I drive it.


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Dave
My 72
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I always use a vented cap. I really don't think it will make a difference, vented or non-vented, as to a gas smell so long as the cap is new. Check to see if any of the hoses are rotted or cracked. The reason for the vented is that a friend of mine once used a non-vented cap promptly colapsing the tank.

Steve R.
 

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Is your vehicle equipped with the original carb, that fed the canister. If the canister has been removed and the carb is venting the bowl into the atmosphere you are likely to smell it, unless the external vent on the carb is malfunctioning, because that shall only vent when the vehicle is shut off, because of the gas boil when the vehicle is shut off. The vent maybe stuck open all the time. Try a good carb rebuild.

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1965 300 deluxe chevelle 327
1978 Corvette Anniversary edition
65 elcamino
65 chevelle wagon
65 4dr malibu
http://www.angelfire.com/co2/coryschevellepage
 

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If you smell gas to the point you are sick you need to stop driving the car until the EXHAUST leak or fuel leak is fixed! I very strongly suspect that is the problem with a bad trunk seal. The car creates a pressure area behind the car that can get pulled in through the car with a bad trunk gasket.

If that much gas was spilling out into your engine compartment you would probably already have burnt the car to a crisp. After a hard acceleration pull to the side of the road (have a fire extinguisher handy) quickly and shut the engine off. Pull the air cleaner and look for gas leaks around the carburator.

Pull a spark plug and see if it is black or dark brown around the center electrode protrusion. This would indicate that the car is also running too rich and adding that to the exhaust problem.

Post what you find and we can help narrow it down further.

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Redrum (or Mike)
68 Corvette - 383 CI 427 HP
69 SS Chevelle being updated to Pro-Touring
97 Z-28
 

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I had a mystery leak once - turned out the harmonic balancer had rubbed it's way through the hardline from the fuel pump to the carb. Amazingly it didn't set the car on fire, but needless to say, it was a little disconcerting...

-Rich
 

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A quick piece of advice. Jack the rear end up and check the top of the gas tank where the fuel line exits. There should be two extra lines running off the tank, one on each side. Make sure they're capped! Those are the vapor recovery lines that run to the canister. If those are left unconnected, anything more than a half tank of fuel will seep out of those connections. AND, don't use those little rubber "vacuum line" caps either. The gas will eat them in very short order. Ask me how I know.

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MalibuJerry350
Original owner '70 Chevelle.
540,000+ miles on car.
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html
 

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Jerry and all,

I thought I'd asked this before, but here goes...I've got the same smell. However, my '68 with no smog (or canister - too early) has both vent hoses on the tank with no caps.
1. Should mine be capped?
2. My stock cap is non-vented. Should I change it?

Thanks!

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David Reinecke - aka - FINE 68
1968 Chevelle 300 Sport Coupe Deluxe
www.geocities.com/jdreinecke
 

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OK, Jerry, how DID you know? No, wait, I think I've got that
. Seriously, what did you use to cap yours?

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Phil
"I don't believe I'da told that"
 

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I can relate to the gas smell problem. I suspected mine was coming from the accelator pump gasket that dried out on my Holley, BUT this issue of the gas tank vents has me wondering. My 69 has a non vented gas cap, on top of the gas tank are two small rubber vent hoses connected to a plastic vent, could this be part of my problem?. The trunk seal is new as is the gas cap. Sounds like my problem could be two-fold.
 

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I wound up with the problem after I replaced my original tank with a tank from a '71 Chevelle which had a recovery canister. My Chevelle, being a '70 non California vehicle, didn't come with a canister, soooo I had these two extra ports on the tank to block off. Not thinking, I used two vacuum line plugs with spring clamps to seal off the open lines. The gas cap, which came with the tank, is a non-vented type. My original tank had a vented cap. Not wanting to drop the tank again, I prefabricated two plugs using a short piece of rubber fuel line with a piece of copper tubing stuck into it with the end of the copper tubing soldered. No more leaks! The old cap doesn't fit very tight so, in reality, it is vented.

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MalibuJerry350
Original owner '70 Chevelle.
540,000+ miles on car.
My Chevelle: http://hometown.aol.com/erie614/myhomepage/index.html
 

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Before I crawl up under there . . . where, exactly, are the lines we're talking about? Are they in the cap that holds the sender unit? Will I need to drop the tank to get to them?
Thanks!

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Phil
"I don't believe I'da told that"
 

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Discussion Starter · #13 ·
Ok, here we go. The carb in the car is not original. The car did originally have the canister but it was missing when I bought it. To pass MD inspection, there needed to be a canister so one was obtained and hooked up. Don't know if it actually worked or not and I don't want it on there anyway. So there is a gas smell with or without the canister. As an interesting aside, with the canister attached, my car would get stuck on fast idle. In gear it would idle at 1K, but in Park or Neutral it would idle up to 2K.

My guess on the smell is a problem with the carb. I am getting an engine tuneup and hopefully the problem will present itself. I would do the tuneup myself if I knew how.

As far as the gas cap goes, I found lots more info on it and no solutions yet. Check out:
http://www.chevelles.com/forum/Forum10/HTML/000134.html http://www.chevelles.com/forum/Forum9/HTML/004105.html http://www.chevelles.com/forum/Forum10/HTML/002712.html
http://www.chevelles.com/forum/Forum1/HTML/005736.html http://www.chevelles.com/forum/Forum1/HTML/005782.html http://www.chevelles.com/forum/Forum1/HTML/006002.html http://www.chevelles.com/forum/Forum1/HTML/006017.html http://www.chevelles.com/forum/Forum1/HTML/006378.html

Also, I noticed what appeared to be a big dent in the bottom of the tank. After reading the threads above now I am wondering if it wasn't a vacuum problem. I'll check it out when I get the car back. Either way, I am not above replacing either the carb or the tank or both to fix this issue. I just wish I knew what it was.

On a side note, is there a larger capacity tank (>20) that someone sells that would fit on the Chevelle?

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Dave
My 72
TC #1114
ACES #4441
MCC #478

[This message has been edited by eDave (edited 03-28-2001).]
 

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Dave, I'd also like to know if anyone knows of a larger gas tank that fits Chevelles. Also, I still need to know where the vent tubes are that we're talking about. Do I have to drop the tank to get to them?

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Phil
"I don't believe I'da told that"
 

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FYI, for YALL's Info. if you buy a vented cap, it will most likely be TOO hard for the gases to escape, i took mine apart (on the other 70 i had, mine now has a fuel cell
) and removed part of the spring, this made it ezier for the pressure to leak out as needed, i tried 2 new caps and they both were too tight, the gas pressure wouldn't release like they should have, (aftermarket junk).

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1970 SS396 AKA 454/4spd
My Chev-Hell Page
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Ft.Worth, Tx
Big Block Chevy.net
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i followed Johns recommedations with good results for my non vented , non canister tank


Gas cap CST 6807

Autozone $3.99

Remove valving mechanism by bending retaing arms and cut relief spring in half then reassemble


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Rich
Cocoa Beach, Fla
Team Chevelle #380
[email protected]
www.chevelles.com/showroom/70_SS_454.jpg

[This message has been edited by 70 SS 454 (edited 03-30-2001).]
 

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Discussion Starter · #17 ·
Phil,
I did some research on the larger gas tank issue and all I could come up with was Rock Valley. They do custom fuel tanks. I talked to one of their guys and he said he could make the tank as big as I wanted


I think it really now becomes an issue of safety. He said on a 72 Chevelle he didn't think there was any room to make it wider so he would have to make it deeper. My 72 isn't here so I don't know how much more room is under there.

You are also talking twice the price of the 20 gallon.

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Dave
My 72
TC #1114
ACES #4441
MCC #478
 

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I recently did the cap swapping thing on my 67 trying to cure a gas leak problem. There would be gas down the filler neck and I couldn't stop it to save my life. One day I spotted a crack in the top of solder joint between the tank and filler tube. I removed the tank cleaned it out, removed the neck and brazed it back on. This may not have anything to do with your problems but if anyone else has to do this be careful.

I'd hate for you to be one of those guys who comes up at the gas station and tells me about his Chevelle he wrapped around a tree or blew up fixing the gas tank.
 
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