73 Charcoal canister
04-17-2014, 06:00 AM
#1
73 Charcoal canister
On the 73 I believe there is a charcoal canister that connects to a return line on the left side of the fuel tank. I think the effect is to reduce vapor lock. While I have the engine out of the car, should I replace anything with this canister? New hoses for sure, thanks for the help.
04-17-2014, 06:44 AM
#2
Drifting
I think there is a filter (flat round) on the bottom. I have not removed mine. I thought it was on the drivers side of the car? Never gave it much thought since the car has been hacked up over the years.
04-18-2014, 04:41 AM
#3
Canister Filter
Thanks very much for the information. Looks like an easy thing to keep in operation.
Hi Frank,
The charcoal canister is part of the emissions control system. The fumes from the gas tank are brought into the canister by vacuum supplied by the engine while it's running rather than being vented to the atmosphere.
The is a 'pancake' filter at the bottom of the canister that can be replaced by removing the bottom lid.
It doesn't really have anything to do with vapor lock.
Regards,
Alan
This is the canister and it's mounting bracket laying on it's side.
This is the bottom lid that pops off.
The charcoal canister is part of the emissions control system. The fumes from the gas tank are brought into the canister by vacuum supplied by the engine while it's running rather than being vented to the atmosphere.
The is a 'pancake' filter at the bottom of the canister that can be replaced by removing the bottom lid.
It doesn't really have anything to do with vapor lock.
Regards,
Alan
This is the canister and it's mounting bracket laying on it's side.
This is the bottom lid that pops off.
04-18-2014, 08:08 AM
#4
Race Director
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Location: North of Toronto - Ontario
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And here's the little filter cloth under that lid, just stuffs under the cross rod.
If you search around you can find some who have cut the grill out and replaced the charcoal (new stuff available from pet stores, ie fish filters)
I didn't have that kind of enthusiasm
If you search around you can find some who have cut the grill out and replaced the charcoal (new stuff available from pet stores, ie fish filters)
I didn't have that kind of enthusiasm
04-18-2014, 08:36 AM
#5
Drifting
will this work as a good "vent to air" canister for a fuel tank that needs a vent? On my C2 resto-mod, I have a TPI setup and it has a small tube charcoal filter about 1" long vented to air. It doesn't collect the fumes at all, so my garage always smells. I've often thought about adding a charcoal canister like this one which has tons more filtering capability.
Thoughts?
Thoughts?
04-18-2014, 06:52 PM
#6
Race Director
Hi CW,
My understanding is that this canister only gathers the gas fumes from the tank because it has 2 hoses hooked to the carburetor which provide a vacuum source to pull the fumes through the 'separator' mounted on the driver's side of the tank and then forward to the canister.
I'm not sure how well it might work without a vacuum source hooked to the canister.
Regards,
Alan
My understanding is that this canister only gathers the gas fumes from the tank because it has 2 hoses hooked to the carburetor which provide a vacuum source to pull the fumes through the 'separator' mounted on the driver's side of the tank and then forward to the canister.
I'm not sure how well it might work without a vacuum source hooked to the canister.
Regards,
Alan
CW...In addition...due to C2's did not have a vapor return line....and if you plan on doing this you might want to consider this part also.
http://www.ebay.com/itm/1970-74-corv...-/181385446521
The fuel tank for a 1974 ...for example has a bracket welded to the side for this above part....and this part makes it so sloshing fuel...when the tank is full...does not easily get sucked into the vapor return line...which it can if this part is left off.
The tank is the same size and will fit if you choose to try to install this system...not knowing what you have currently for a fuel tank/sending unit/etc.
The reason that this set-up will aid you is that ...in conjunction with a proper vented cap...will not allow fuel vapor to be able to escape. Unless the engine is running and vacuum from the canister is connected PORTED vacuum and the supply from the tank connected and the large 1/4" hose getting tied into your PCV that would have a "T" at the end of it (one for a 1984 Corvette will do)...you should have NO fumes.
DUB
04-18-2014, 10:01 PM
#7
Drifting
My setup has a vent tube from the tank with a 1" charcoal filter that was vented to air. My cap is a vent style. It always smelled the garage full of gas fumes.
I ended up plugging the filter to see what it would do. Immediately the gas fumes went away. At that point my tank has built up pressure. When I take the cap off, I gave to do it slowly to release the pressure.
I'm assuming I need to reattach some sort of filter vented to air to eliminate the smell and back pressure.
That's the issue and why i was wondering if the c3 canister could work, vented to air.
Thoughts???
I ended up plugging the filter to see what it would do. Immediately the gas fumes went away. At that point my tank has built up pressure. When I take the cap off, I gave to do it slowly to release the pressure.
I'm assuming I need to reattach some sort of filter vented to air to eliminate the smell and back pressure.
That's the issue and why i was wondering if the c3 canister could work, vented to air.
Thoughts???
04-18-2014, 10:38 PM
#8
Burning Brakes
The canister is useless. It merely filters fumes that are fed into the carb to be reburned.
Throw it and all plumbing away. Plug any lines.
Buy a vented gas cap.
If your car stinks of gas you have some other problem.
Throw it and all plumbing away. Plug any lines.
Buy a vented gas cap.
If your car stinks of gas you have some other problem.
04-19-2014, 09:02 AM
#9
Burning Brakes
[QUOTE=Alan 71;1586695516]Hi cw,
You don't notice the smell of the gas that a vented cap allows until you have the car parked in an attached garage and your wife wants to know why your house smells like gas.
Regards,
Alan
/QUOTE]
A vented gas cap works by using a one way pressure release valve.
Simply put, as gas is used in the car, the vented cap allows air into the tank to equalize pressure. It doesn't vent as it sits parked.
There are very little, if any gas fumes vented to the garage. IF you smell gas in your garage, you have an opening to your gas tank somewhere.
(there is also a vent return line on Corvette fuel pumps)
Unless you are running your car in the garage for hours at a time draining the tank the allowing the air to equalize in the tank, you won't have gas fumes in your garage. (exhaust gas will have long killed you anyway)
There are literally millions and millions of cars. trucks, motorcycles, yard tractors, lawn mowers, hedge trimmers etc with vented caps.
You don't smell gas fumes.
The system is utterly useless for any practical purpose on the car. It does not improve performance. It does not reduce gas smell. It does little, if anything, for the environment.
If you want the system for historic purposes, by all means use it.
You don't have to go through all the expense and trouble of actually rebuilding it. Just hang it there for looks, and run all that extra plumbing to your carb.
To compare these early systems to modern eco systems is just
You don't notice the smell of the gas that a vented cap allows until you have the car parked in an attached garage and your wife wants to know why your house smells like gas.
Regards,
Alan
/QUOTE]
A vented gas cap works by using a one way pressure release valve.
Simply put, as gas is used in the car, the vented cap allows air into the tank to equalize pressure. It doesn't vent as it sits parked.
There are very little, if any gas fumes vented to the garage. IF you smell gas in your garage, you have an opening to your gas tank somewhere.
(there is also a vent return line on Corvette fuel pumps)
Unless you are running your car in the garage for hours at a time draining the tank the allowing the air to equalize in the tank, you won't have gas fumes in your garage. (exhaust gas will have long killed you anyway)
There are literally millions and millions of cars. trucks, motorcycles, yard tractors, lawn mowers, hedge trimmers etc with vented caps.
You don't smell gas fumes.
The system is utterly useless for any practical purpose on the car. It does not improve performance. It does not reduce gas smell. It does little, if anything, for the environment.
If you want the system for historic purposes, by all means use it.
You don't have to go through all the expense and trouble of actually rebuilding it. Just hang it there for looks, and run all that extra plumbing to your carb.
To compare these early systems to modern eco systems is just
04-19-2014, 09:18 AM
#10
Drifting
Guys
The issue is not the vent cap. It's the fact that my tank has a vent tube, vented to air. That's where the smell came from. Once I plugged it, the gas smell went away. The vent cap let's air in like it's supposed to.
The problem now is the tank builds up back pressure especially on hot summer days. If I unplug the vent line, the tank breaths but then the fumes are back. I'm wondering if there is a better vent system that doesn't go back to the carb(EFI in my case), that will minimize the fumes.
The issue is not the vent cap. It's the fact that my tank has a vent tube, vented to air. That's where the smell came from. Once I plugged it, the gas smell went away. The vent cap let's air in like it's supposed to.
The problem now is the tank builds up back pressure especially on hot summer days. If I unplug the vent line, the tank breaths but then the fumes are back. I'm wondering if there is a better vent system that doesn't go back to the carb(EFI in my case), that will minimize the fumes.
04-19-2014, 09:38 AM
#11
Team Owner
Member Since: Sep 2006
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O.K., Commander you're right.
Regards,
Alan
Regards,
Alan
04-19-2014, 12:03 PM
#12
Burning Brakes
Guys
The issue is not the vent cap. It's the fact that my tank has a vent tube, vented to air. That's where the smell came from. Once I plugged it, the gas smell went away. The vent cap let's air in like it's supposed to.
The problem now is the tank builds up back pressure especially on hot summer days. If I unplug the vent line, the tank breaths but then the fumes are back. I'm wondering if there is a better vent system that doesn't go back to the carb(EFI in my case), that will minimize the fumes.
The issue is not the vent cap. It's the fact that my tank has a vent tube, vented to air. That's where the smell came from. Once I plugged it, the gas smell went away. The vent cap let's air in like it's supposed to.
The problem now is the tank builds up back pressure especially on hot summer days. If I unplug the vent line, the tank breaths but then the fumes are back. I'm wondering if there is a better vent system that doesn't go back to the carb(EFI in my case), that will minimize the fumes.
The following is a picture from the 71 Assembly Manuel. Not sure how the 73 differs, if it does.
It sounds like someone might have "adjusted" the left side of your tank where the lines are. You should not have a "vent" line to atmosphere at all.
You may have a defective vented gas cap if plugging the "vent" line builds up some sort of pressure in the tank. That shouldn't happen.
Our Vettes have a very rudimentary smog system.
Modern cars have fuel tank pressure sensors connected to the Computer in the car to monitor the system for fume leaks. Some allow the tank to pressurize a few pounds, or contribute vacuum, to aid in recirculating the fumes to the fuel injection. The computer is constantly adjusting this according to altitude, temperature and a plethora of other conditions.
04-19-2014, 05:00 PM
#13
Race Director
If you modify or get your fuel vapor system to be like what is pictured above...using the separator that I posted in my post.
IF the fuel vapor line is good...fuel cap does not allow air to blow through it...but if sucked on...the valve opens to allow air into the tank...and you connect the charcoal canister to your car...you will not run into a fuel tank pressure issue...due to every time you step on the gas pedal...fuel vapors are being drawn from the tank and into the engine.
I service NUMEROUS C4 Corvettes yearly whose vapor return line have been plugged....and often times froze up and split the tubing. And once the system is put back as designed...no more fuel smell. And the fuel tank is NOT under pressure...because the fuel cap ALLOWS air into the gas tank...but NOT out. So if I possibly mistakenly wrote a "vented cap" I do NOT mean that it vents out to the atmosphere. I apologize for any confusing if that came across as if it vents to the outside air. Thanks Pete.
The charcoal canister is NOT useless...it has a purpose. Some may feel otherwise...and that is there choice...but it does work....and is still being installed on 2013 Corvettes. Go figure.
I do not know if your car has a fuel return coming off the fuel pump. I have had some Corvette (C2 era) that would have a fuel tank pressurizing issue so badly ...that it would actually allow fuel to seep past the needle and seat and drip profusely into the carb when it was shut off...and when the fuel cap was removed...it would stop immediately.
I am sorry but I have to comment on issues that I feel are not quite correct.
Then what should someone do in your opinion? I am interested in what you think...because if you have a system that works..I am all ears.
DUB
IF the fuel vapor line is good...fuel cap does not allow air to blow through it...but if sucked on...the valve opens to allow air into the tank...and you connect the charcoal canister to your car...you will not run into a fuel tank pressure issue...due to every time you step on the gas pedal...fuel vapors are being drawn from the tank and into the engine.
I service NUMEROUS C4 Corvettes yearly whose vapor return line have been plugged....and often times froze up and split the tubing. And once the system is put back as designed...no more fuel smell. And the fuel tank is NOT under pressure...because the fuel cap ALLOWS air into the gas tank...but NOT out. So if I possibly mistakenly wrote a "vented cap" I do NOT mean that it vents out to the atmosphere. I apologize for any confusing if that came across as if it vents to the outside air. Thanks Pete.
The charcoal canister is NOT useless...it has a purpose. Some may feel otherwise...and that is there choice...but it does work....and is still being installed on 2013 Corvettes. Go figure.
I do not know if your car has a fuel return coming off the fuel pump. I have had some Corvette (C2 era) that would have a fuel tank pressurizing issue so badly ...that it would actually allow fuel to seep past the needle and seat and drip profusely into the carb when it was shut off...and when the fuel cap was removed...it would stop immediately.
I am sorry but I have to comment on issues that I feel are not quite correct.
A vented gas cap works by using a one way pressure release valve.
AGREED
Simply put, as gas is used in the car, the vented cap allows air into the tank to equalize pressure. It doesn't vent as it sits parked.
YES to allowing air in...but if pressure is building upo due to no vent on the tank...air can not be pulled in...and by what means would it be able to be pulled in...and YES...the cap will not allow fuel vapors to pass by it to the outside.
There are very little, if any gas fumes vented to the garage. IF you smell gas in your garage, you have an opening to your gas tank somewhere.
YES..if you smell fuel...you have a problem ...somewhere
(there is also a vent return line on Corvette fuel pumps)
NOT a "vent return line...but a fuel return line...which is why the fuel tank can build pressure due to the fuel is being circulated and agitated. Those of you who do not believe me..It occurs with lacquer thinner...as many painters know. Put some thinner in your paint gun..seal the lid...close the vent hole in the lid...shake it up a few times...and the pressure from the thinner will shoot out of the gun when the trigger is pulled...and TRUST ME...GAS does the same thing but even more exaggerated. This is how yoru fuel tank is getting pressurized...circulating fuel and summer temps. BUT do not believe me.
Unless you are running your car in the garage for hours at a time draining the tank the allowing the air to equalize in the tank, you won't have gas fumes in your garage. (exhaust gas will have long killed you anyway)
?
There are literally millions and millions of cars. trucks, motorcycles, yard tractors, lawn mowers, hedge trimmers etc with vented caps.
I do not know where you were going with this statement...but each of these examples...many of which..I guess only apply if the comment was in regards to the system was designed to its entirety to NOT allow fuel smells to escape.
You don't smell gas fumes.
?
The system is utterly useless for any practical purpose on the car. It does not improve performance. It does not reduce gas smell. It does little, if anything, for the environment.
I disagree...because charcoal canisters are still being installed for a reason...and it would seem pointless if these systems.. in your opinion...which is fine.... were/are useless...then why are they still being used and installed on new Corvettes?
If you want the system for historic purposes, by all means use it.
Not so much for historic...but because the system will work due to allowing vapors to be pulled into the engine...thus stopping any pressurization of the fuel tank.
To compare these early systems to modern eco systems is just
But the 2013 Corvette still uses a charcoal canister...how much more "modern" does someone have to go?
AGREED
Simply put, as gas is used in the car, the vented cap allows air into the tank to equalize pressure. It doesn't vent as it sits parked.
YES to allowing air in...but if pressure is building upo due to no vent on the tank...air can not be pulled in...and by what means would it be able to be pulled in...and YES...the cap will not allow fuel vapors to pass by it to the outside.
There are very little, if any gas fumes vented to the garage. IF you smell gas in your garage, you have an opening to your gas tank somewhere.
YES..if you smell fuel...you have a problem ...somewhere
(there is also a vent return line on Corvette fuel pumps)
NOT a "vent return line...but a fuel return line...which is why the fuel tank can build pressure due to the fuel is being circulated and agitated. Those of you who do not believe me..It occurs with lacquer thinner...as many painters know. Put some thinner in your paint gun..seal the lid...close the vent hole in the lid...shake it up a few times...and the pressure from the thinner will shoot out of the gun when the trigger is pulled...and TRUST ME...GAS does the same thing but even more exaggerated. This is how yoru fuel tank is getting pressurized...circulating fuel and summer temps. BUT do not believe me.
Unless you are running your car in the garage for hours at a time draining the tank the allowing the air to equalize in the tank, you won't have gas fumes in your garage. (exhaust gas will have long killed you anyway)
?
There are literally millions and millions of cars. trucks, motorcycles, yard tractors, lawn mowers, hedge trimmers etc with vented caps.
I do not know where you were going with this statement...but each of these examples...many of which..I guess only apply if the comment was in regards to the system was designed to its entirety to NOT allow fuel smells to escape.
You don't smell gas fumes.
?
The system is utterly useless for any practical purpose on the car. It does not improve performance. It does not reduce gas smell. It does little, if anything, for the environment.
I disagree...because charcoal canisters are still being installed for a reason...and it would seem pointless if these systems.. in your opinion...which is fine.... were/are useless...then why are they still being used and installed on new Corvettes?
If you want the system for historic purposes, by all means use it.
Not so much for historic...but because the system will work due to allowing vapors to be pulled into the engine...thus stopping any pressurization of the fuel tank.
To compare these early systems to modern eco systems is just
But the 2013 Corvette still uses a charcoal canister...how much more "modern" does someone have to go?
DUB
04-19-2014, 07:40 PM
#14
Burning Brakes
I service NUMEROUS C4 Corvettes yearly whose vapor return line have been plugged....and often times froze up and split the tubing. And once the system is put back as designed...no more fuel smell.
I agree fully. The system will not smell of gas if working properly. BUT, neither will it smell of gas if the extra stuff is removed
And the fuel tank is NOT under pressure...because the fuel cap ALLOWS air into the gas tank...but NOT out. So if I possibly mistakenly wrote a "vented cap" I do NOT mean that it vents out to the atmosphere. I apologize for any confusing if that came across as if it vents to the outside air. Thanks Pete.
The OP stated that his issue was some sort of vent line on the side of his tank. He stated that when he plugged it pressure builds up in the tank and he has a vented cap. He should not have a separate vent at all. It is essentially a closed system.
The charcoal canister is NOT useless...it has a purpose. Some may feel otherwise...and that is there choice...but it does work....and is still being installed on 2013 Corvettes. Go figure.
Environmental regulation began in the early 1970s. Cars have had evaporative emission control (EVAP) systems ever since. These systems are designed to store and dispose of fuel vapors before they can escape into the atmosphere.
The modern systems work much better because the computers are much better, there are more sensors and combined with fuel injection, work better.
You can find everything you want to know about the canister system here:
http://technologyinterface.nmsu.edu/5_1/5_1e/5_1e.html
You can also find out how to rebuild your canister here:
http://www.i-car.com/pdf/upcr/procedures/em/em11.pdf
Then what should someone do in your opinion? I am interested in what you think...because if you have a system that works..I am all ears.
I don't use one on my classic sports car. Therefore the car works perfect.
I am sorry but I have to comment on issues that I feel are not quite correct.
DUB
I agree fully. The system will not smell of gas if working properly. BUT, neither will it smell of gas if the extra stuff is removed
And the fuel tank is NOT under pressure...because the fuel cap ALLOWS air into the gas tank...but NOT out. So if I possibly mistakenly wrote a "vented cap" I do NOT mean that it vents out to the atmosphere. I apologize for any confusing if that came across as if it vents to the outside air. Thanks Pete.
The OP stated that his issue was some sort of vent line on the side of his tank. He stated that when he plugged it pressure builds up in the tank and he has a vented cap. He should not have a separate vent at all. It is essentially a closed system.
The charcoal canister is NOT useless...it has a purpose. Some may feel otherwise...and that is there choice...but it does work....and is still being installed on 2013 Corvettes. Go figure.
Environmental regulation began in the early 1970s. Cars have had evaporative emission control (EVAP) systems ever since. These systems are designed to store and dispose of fuel vapors before they can escape into the atmosphere.
The modern systems work much better because the computers are much better, there are more sensors and combined with fuel injection, work better.
You can find everything you want to know about the canister system here:
http://technologyinterface.nmsu.edu/5_1/5_1e/5_1e.html
You can also find out how to rebuild your canister here:
http://www.i-car.com/pdf/upcr/procedures/em/em11.pdf
Then what should someone do in your opinion? I am interested in what you think...because if you have a system that works..I am all ears.
I don't use one on my classic sports car. Therefore the car works perfect.
I am sorry but I have to comment on issues that I feel are not quite correct.
DUB
(there is also a vent return line on Corvette fuel pumps)
NOT a "vent return line...but a fuel return line...which is why the fuel tank can build pressure due to the fuel is being circulated and agitated.
Yes, it is a fuel and vapor return line. It is there to prevent vapor lock due to the temperature changes you describe. Especially after the car is shut off and the engine gets hotter
There are literally millions and millions of cars. trucks, motorcycles, yard tractors, lawn mowers, hedge trimmers etc with vented caps.
I do not know where you were going with this statement...but each of these examples...many of which..I guess only apply if the comment was in regards to the system was designed to its entirety to NOT allow fuel smells to escape.
It is simple. Harleys have vented gas caps. And no gas smell. If you have a gas smell, something is wrong, but not because of a vented cap.
The system is utterly useless for any practical purpose on the car.It does not improve performance. It does not reduce gas smell. It does little, if anything, for the environment.
I disagree...because charcoal canisters are still being installed for a reason...and it would seem pointless if these systems.. in your opinion...which is fine.... were/are useless...then why are they still being used and installed on new Corvettes?
Disagree all you want. The system does not in the least, tiniest bit affect the operation of the car if removed.
The amount of gas fumes vented to the atmosphere is like cow farts. Now the Government wants to regulate cow farts. I guess if you are a farmer soon you'll have to hang charcoal canisters on the butts.
http://www.foxnews.com/science/2013/...ries-spew-gas/
The fact of the matter is, I drive a 33 year old sports car to shows and on Sunday to take the wife or grandkids for ice cream. I don't consider the gas "fumes" to be a significant contributor to air pollution.
In fact, I know some people that should have charcoal canisters attached to their butts.
NOT YOU NOT YOU....dont' take it personal, just a joke.
Last edited by commander_47; 04-19-2014 at 07:43 PM.
04-20-2014, 06:56 PM
#15
Race Director
Commander 47.
I am in agreement with much of what you commented on...and I also know the newer systems...being computer controlled are much more efficient.
The only issue that I have encountered MANY times. Is that when the charcoal canister/vent line system are NOT working or intact. That I have had Corvettes have an issue with the fuel tank being under pressure. And I know it does not apply in the original posters problem...but...I work on a lot of C4's...which have a plastic bladder in the fuel tank...and the vapor line is "T"'d off so the vapor line going to the charcoal canister is pulling from BOTH sides of the plastic bladder....and knowing that the fuel cap can allow air to be drawn in when needed...but not out...it keeps the system in balance.
I understand that the charcoal canister does nothing for increasing engine performance.
What gets me is all the "stuff" I have to do to maintain and keep and emission EVAP system operational on these Corvettes. When re-programming and such on some of the "bullets" I work on and how I am "controlled" in what can be done on a street car and still be emission compliant...which I am all for. AND what is really WEIRD...if you stop and think about it....with all of the concerns on what a car has on it...it is ODD that the gas stations..who SELL the fuel...do not have to have catalysts for the VENT PIPES that go into the atmosphere for all of the underground fuel tanks...FUNNY AIN"T IT!
IT ALL ADDS UP.
DUB
I am in agreement with much of what you commented on...and I also know the newer systems...being computer controlled are much more efficient.
The only issue that I have encountered MANY times. Is that when the charcoal canister/vent line system are NOT working or intact. That I have had Corvettes have an issue with the fuel tank being under pressure. And I know it does not apply in the original posters problem...but...I work on a lot of C4's...which have a plastic bladder in the fuel tank...and the vapor line is "T"'d off so the vapor line going to the charcoal canister is pulling from BOTH sides of the plastic bladder....and knowing that the fuel cap can allow air to be drawn in when needed...but not out...it keeps the system in balance.
I understand that the charcoal canister does nothing for increasing engine performance.
What gets me is all the "stuff" I have to do to maintain and keep and emission EVAP system operational on these Corvettes. When re-programming and such on some of the "bullets" I work on and how I am "controlled" in what can be done on a street car and still be emission compliant...which I am all for. AND what is really WEIRD...if you stop and think about it....with all of the concerns on what a car has on it...it is ODD that the gas stations..who SELL the fuel...do not have to have catalysts for the VENT PIPES that go into the atmosphere for all of the underground fuel tanks...FUNNY AIN"T IT!
IT ALL ADDS UP.
DUB
04-21-2014, 08:12 AM
#16
Burning Brakes
I just want to try and bring this back to the OP's dilemma.
The car should not ever vent to atmosphere at all.
If it has a non vented gas cap, but a vent to atmosphere, then you will smell gas in your garage.
If the system is sealed, and you have a vented gas cap it won't smell of gas.
IF the system is 100% stock it should NOT have a vented gas cap, and it won't smell of gas. The stock system is designed so that motor vacuum will draw the fumes into the canister for burning in the motor.
Some things you might want to do:
Check to make sure your vented gas cap is working.
Consider removing the entire fume recovery system on your 73. A little known secret is that these early systems are not very effective for the environment. Losing the system and keeping your car well tuned and healthy will have nominal, if any, affect on the environment.
If keeping the system make sure all lines are NOT plugged. The charcoal in your canister is long played out. But the charcoal doesn't restrict air flow anyways, unless it is plugged up for some reason. (very unlikely)
I suspect in your case, someone just vented the tank to atmosphere by opening up one of the connections numbered 1 thru 5 in the diagram. If they did that, you may still have a non vented cap.
The car should not ever vent to atmosphere at all.
If it has a non vented gas cap, but a vent to atmosphere, then you will smell gas in your garage.
If the system is sealed, and you have a vented gas cap it won't smell of gas.
IF the system is 100% stock it should NOT have a vented gas cap, and it won't smell of gas. The stock system is designed so that motor vacuum will draw the fumes into the canister for burning in the motor.
Some things you might want to do:
Check to make sure your vented gas cap is working.
Consider removing the entire fume recovery system on your 73. A little known secret is that these early systems are not very effective for the environment. Losing the system and keeping your car well tuned and healthy will have nominal, if any, affect on the environment.
If keeping the system make sure all lines are NOT plugged. The charcoal in your canister is long played out. But the charcoal doesn't restrict air flow anyways, unless it is plugged up for some reason. (very unlikely)
I suspect in your case, someone just vented the tank to atmosphere by opening up one of the connections numbered 1 thru 5 in the diagram. If they did that, you may still have a non vented cap.
04-22-2014, 12:12 PM
#17
Charcoal canister
A lot of interesting discussion on this topic. Thanks for all the input. I'm going to keep the system in service. Shouldn't be a bad thing if GM designed it. I so look forward to finally driving my Vette!
I just want to try and bring this back to the OP's dilemma.
The car should not ever vent to atmosphere at all.
If it has a non vented gas cap, but a vent to atmosphere, then you will smell gas in your garage.
If the system is sealed, and you have a vented gas cap it won't smell of gas.
IF the system is 100% stock it should NOT have a vented gas cap, and it won't smell of gas. The stock system is designed so that motor vacuum will draw the fumes into the canister for burning in the motor.
Some things you might want to do:
Check to make sure your vented gas cap is working.
Consider removing the entire fume recovery system on your 73. A little known secret is that these early systems are not very effective for the environment. Losing the system and keeping your car well tuned and healthy will have nominal, if any, affect on the environment.
If keeping the system make sure all lines are NOT plugged. The charcoal in your canister is long played out. But the charcoal doesn't restrict air flow anyways, unless it is plugged up for some reason. (very unlikely)
I suspect in your case, someone just vented the tank to atmosphere by opening up one of the connections numbered 1 thru 5 in the diagram. If they did that, you may still have a non vented cap.
The car should not ever vent to atmosphere at all.
If it has a non vented gas cap, but a vent to atmosphere, then you will smell gas in your garage.
If the system is sealed, and you have a vented gas cap it won't smell of gas.
IF the system is 100% stock it should NOT have a vented gas cap, and it won't smell of gas. The stock system is designed so that motor vacuum will draw the fumes into the canister for burning in the motor.
Some things you might want to do:
Check to make sure your vented gas cap is working.
Consider removing the entire fume recovery system on your 73. A little known secret is that these early systems are not very effective for the environment. Losing the system and keeping your car well tuned and healthy will have nominal, if any, affect on the environment.
If keeping the system make sure all lines are NOT plugged. The charcoal in your canister is long played out. But the charcoal doesn't restrict air flow anyways, unless it is plugged up for some reason. (very unlikely)
I suspect in your case, someone just vented the tank to atmosphere by opening up one of the connections numbered 1 thru 5 in the diagram. If they did that, you may still have a non vented cap.
