Fuel Tank Vent Breather??
#1
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Fuel Tank Vent Breather??
Have 86 Camaro, has a filter/breather on end of hose from gas tank, anyone know were i might find one. GM discontinued.
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Re: Fuel Tank Vent Breather??
We're you ever able to find this part. If not, what was your solution to this. I just installed a new fuel pump and sending unit and this EVAP vent broke into a few pieces.
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Re: Fuel Tank Vent Breather??
I ran into this problem. Zip tie a little screen over then end of the hose and let it hang. All that vent is is when the tank reaches too much pressure it purges it out I've had zero problem since then.. My tank was building massive pressure and I couldn't figure out why but I fixed it now )
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Re: Fuel Tank Vent Breather??
If that's what your talking about, they are hard to find new. You might find a good used one if you look around. My understanding is that this is a vacuum relief valve not a pressure relief valve. It's supposed to let air in the tank if a vacuum develops from gas being sucked out, a situation that almost never happens with our cars. Most of us have problems with pressure build up in the tank which is a whole different issue this valve has nothing to do with. If you remove it and don't plug the line, you will relive the pressure in the tank but you will be venting raw fuel vapor into the air. I think you might get along just fine without this valve, but I would plug the line if you remove it.
#5
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Re: Fuel Tank Vent Breather??
The remote vent valve on a 3rd gen serves a similar purpose to a vented gas cap. For emissions reasons, the factory doesn't want fuel vapors just wafting out of the tank into the atmosphere. They want them to push up the line that goes to the charcoal canister under the hood where it is captured and then purged and burned in the engine the next time you drive it.
As such, those valves typically serve TWO purposes. 1. As a vacuum relief- allowing air into the tank if a vacuum should develop 2. As a tank pressure control valve- holding in some pressure to work the charcoal canister system, but with an overload valve to allow it to vent to atmosphere if that pressure becomes excessive (so as not to damage or rupture the thin sheet metal gas tank).
As a vacuum relief, it takes almost no differential to suck air back into the tank through the valve. As a pressure relief it's got a spring-loaded one-way valve that takes some considerable pressure to open. More than you could possibly generate trying to blow through it with your mouth.
As such, those valves typically serve TWO purposes. 1. As a vacuum relief- allowing air into the tank if a vacuum should develop 2. As a tank pressure control valve- holding in some pressure to work the charcoal canister system, but with an overload valve to allow it to vent to atmosphere if that pressure becomes excessive (so as not to damage or rupture the thin sheet metal gas tank).
As a vacuum relief, it takes almost no differential to suck air back into the tank through the valve. As a pressure relief it's got a spring-loaded one-way valve that takes some considerable pressure to open. More than you could possibly generate trying to blow through it with your mouth.
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Re: Fuel Tank Vent Breather??
Thanks! So I should get away with installing a filtered one-way check valve, and vented cap it seems.
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Re: Fuel Tank Vent Breather??
Yes that should be ok. Just another thought, I removed mine and cleaned it up and actually broke it free. I read somewhere that it should only take 1pound of pressure to collapse the diaphram. Perhaps you could remove the old one and try to get it broke loose. But as I stated above I left mine completely off.
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Re: Fuel Tank Vent Breather??
The remote vent valve on a 3rd gen serves a similar purpose to a vented gas cap. For emissions reasons, the factory doesn't want fuel vapors just wafting out of the tank into the atmosphere. They want them to push up the line that goes to the charcoal canister under the hood where it is captured and then purged and burned in the engine the next time you drive it.
As such, those valves typically serve TWO purposes. 1. As a vacuum relief- allowing air into the tank if a vacuum should develop 2. As a tank pressure control valve- holding in some pressure to work the charcoal canister system, but with an overload valve to allow it to vent to atmosphere if that pressure becomes excessive (so as not to damage or rupture the thin sheet metal gas tank).
As a vacuum relief, it takes almost no differential to suck air back into the tank through the valve. As a pressure relief it's got a spring-loaded one-way valve that takes some considerable pressure to open. More than you could possibly generate trying to blow through it with your mouth.
As such, those valves typically serve TWO purposes. 1. As a vacuum relief- allowing air into the tank if a vacuum should develop 2. As a tank pressure control valve- holding in some pressure to work the charcoal canister system, but with an overload valve to allow it to vent to atmosphere if that pressure becomes excessive (so as not to damage or rupture the thin sheet metal gas tank).
As a vacuum relief, it takes almost no differential to suck air back into the tank through the valve. As a pressure relief it's got a spring-loaded one-way valve that takes some considerable pressure to open. More than you could possibly generate trying to blow through it with your mouth.
#9
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Re: Fuel Tank Vent Breather??
Correct. Leaving it vented to atmosphere will not hurt the functioning of the engine in any way. Your car will likely have more "fuel smell" if you park it in the garage after driving it for a while, but if you can deal with that, you're fine.
#11
Re: Fuel Tank Vent Breather??
Hey, I know I'm a little late to this, but I was wondering if this fuel vent had anything to do with the charcoal canister, or if it connects to something else besides the fuel tank? My 91firebird failed arizona emissions for not holding pressure, and I'm trying to get it registered again. Thanks if anyone replies!
Last edited by Roger91; 06-04-2020 at 07:44 PM. Reason: Title
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Re: Fuel Tank Vent Breather??
Welcome aboard thirdgen.org.
That valve has its own connection on top of the tank. It isn't otherwise connected to the charcoal canister.
Not sure where they are pressurizing your system for the emissions test (in Colorado, they test the fuel tank cap itself to verify it holds pressure). Can you describe the test you're failing in more detail?
That valve has its own connection on top of the tank. It isn't otherwise connected to the charcoal canister.
Not sure where they are pressurizing your system for the emissions test (in Colorado, they test the fuel tank cap itself to verify it holds pressure). Can you describe the test you're failing in more detail?
#13
Re: Fuel Tank Vent Breather??
Hey guys so I don’t have this vent breather at all and my garage smells like straight fuel so question could I block that hole off and just get a venting gas cap if I was reading that right and could stop the issue?? I have a 1988 camaro
#14
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Re: Fuel Tank Vent Breather??
The system is designed to vent the vapor into a charcoal canister, and the vent valve in question HOLDS pressure (and vacuum) in the tank unless the pressure or vacuum is outside of the specifications of the valve, causing it to open.
The proper components are difficult to find, but even one that's not perfect can be made functional - a little cleaning and maybe some fabrication:
https://www.thirdgen.org/forums/tech...ent-valve.html
GD
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Re: Fuel Tank Vent Breather??
Just checking if anyone knows of a viable option to put on this as the original is not available? Perhaps another years?
#16
Re: Fuel Tank Vent Breather??
I just cleaned my fuel tank valve as described above, and I am still getting a very strong odor of gas emanating from around the gas tank. Nothing is dripping, it's just fumes, but it reeks. What is the next step?
#17
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Re: Fuel Tank Vent Breather??
If you actually sure it is coming from the gas tank, your going to have to get under there to check everything out. Lift the rear end like your going to change the fuel pump and get everything blocking your inspection out of the way (heat shields, etc., probably even have to drop the rear end and such) DONT WORRY, it's easier than it sounds, plenty of vids if your unsure. The fuel smell has to come from fuel, so inspect everything that has the fuel/vapors in it. check your tank over real good. Check your fuel lines/sending unit coming out of the tank (these do have rubber lines between the lines under the car and to the sending unit). Your vent lines. Remember, if you haven't changed anything on this, it's probably 30 or so years old, so the rubber is most likely shot/something cracked/rusted - something along those lines... If you don't find it there, keep following the fuel/vapor lines to the front til you do find it.
#18
Re: Fuel Tank Vent Breather??
If you actually sure it is coming from the gas tank, your going to have to get under there to check everything out. Lift the rear end like your going to change the fuel pump and get everything blocking your inspection out of the way (heat shields, etc., probably even have to drop the rear end and such) DONT WORRY, it's easier than it sounds, plenty of vids if your unsure. The fuel smell has to come from fuel, so inspect everything that has the fuel/vapors in it. check your tank over real good. Check your fuel lines/sending unit coming out of the tank (these do have rubber lines between the lines under the car and to the sending unit). Your vent lines. Remember, if you haven't changed anything on this, it's probably 30 or so years old, so the rubber is most likely shot/something cracked/rusted - something along those lines... If you don't find it there, keep following the fuel/vapor lines to the front til you do find it.
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