Charcoal Cannister

Is the charcoal canister necessary? It has been there since the car was new I am sure, and not even sure it is functional any more.

It's not necessary by any means. I removed the ones off my 72 and 70 California emissions. HOWEVER, the canister should have a line running to the gas tank to vent it so if you plug off the line after you remove it then you'll need to get a vented gas cap. You'll also want to plug the line going to your air cleaner if you use a stock air cleaner or aftermarket with the 1 inch-ish vent tube.

Well, I guess you don't NEED to get a vented gas cap but it's highly recommended since your gas tank won't have any air flow to help push the gas. You can by the standard 69-70 gas cap w/o emissions from CJPonyParts. Check this forum for discussions on vented & non-vented gas caps.

I would like to have my cannister working but there is no place to attach it on the current air cleaner.

If I am not mistaken, vented caps are a must on our cars.

mike

the charcoal canister can be removed from the car as it will not cause any immediate issues, as long as you vent the tank.

you can vent the tank by using a earlier 1970 style gas cap that is vented to atmosphere this is assuming you plug the vapor return line at the top of the fuel tank that goes into the charcoal canistor

however the canister does provide a few useful functions on the car.

First if your fuel tank has not imploded from vacuum caused by the fuel pump sucking the fuel into the carburetor, then yes the charcoal can is working fine. 71-73 cars used non-vented fuel caps thus if the charcoal can was clogged up it would cause a vacuum to form inside the fuel tank. As the fuel level dropped the vacuum would raise, and BOOM fuel tank implosion.

1) emissions; it reduces the amount of evaporated fuel vapor in the air. you get that fuel smell if a car is sitting a long time.

2) the charcoal can acts as a filter between the air base and the fuel tank and carburetor fuel bowls, it provides a constant flow of exchanged air to the fuel tank and carb fuel bowls. this constant change of air sucks out the moisture build up you get inside the bowl and fuel tank. it reduces or eliminates internal corrosion(depends how much you drive the car) thus rust does not form inside the fuel tanks and form scale that falls into the bottom of the tank that either gets stuck against the fuel filter sock clogging the fuel inlet to the fuel line, or gets into the fuel line gets up to the carburetor and clogs all the small fuel bleed circuits.

3) since the tank is not vented when the car is sitting the fuel cannot evaporate, and will take much longer to go bad if the car sits for years.

Basically the charcoal canister is the PCV of the fuel system. the function is similar. a PCV sucks the extra vapors from the valve covers and reduces oil varnish from forming it also creates a slight negative pressure inside the engine that stops small leaks of oil. the charocal canister is located in the air base, so there is an exchange of positive and negative air pressure as you drive, the pcv is located after the carb in the intake manifold so it will always see negative pressure.

so there is an emissions aspect to the charcoal canister, it reduced the millions of gallons of fuel lost as vapor to the atmosphere its introduction improved air quality just as a PCV did the same for oil leaks and clogged up engine oil. but the charcoal can also keeps your fuel system in better condition removing moisture build up and preventing rust formation inside the fuel system.

you can also buy an elbow for an aftermarket air filter base, drill a hole in the air cleaner body and pop a hose connector into it then you will have a pcv vent connection and a fuel vapor can connection. the pcv is a controlled vacuum leak so the vent for one valve cover gets fresh air through the air cleaner base, and the other side is connected to the pcv and goes to full manifold vacuum.

the charcoal canister can be removed from the car as it will not cause any immediate issues, as long as you vent the tank.

you can vent the tank by using a earlier 1970 style gas cap that is vented to atmosphere this is assuming you plug the vapor return line at the top of the fuel tank that goes into the charcoal canistor

however the canister does provide a few useful functions on the car.

First if your fuel tank has not imploded from vacuum caused by the fuel pump sucking the fuel into the carburetor, then yes the charcoal can is working fine. 71-73 cars used non-vented fuel caps thus if the charcoal can was clogged up it would cause a vacuum to form inside the fuel tank. As the fuel level dropped the vacuum would raise, and BOOM fuel tank implosion.

1) emissions; it reduces the amount of evaporated fuel vapor in the air. you get that fuel smell if a car is sitting a long time.

2) the charcoal can acts as a filter between the air base and the fuel tank and carburetor fuel bowls, it provides a constant flow of exchanged air to the fuel tank and carb fuel bowls. this constant change of air sucks out the moisture build up you get inside the bowl and fuel tank. it reduces or eliminates internal corrosion(depends how much you drive the car) thus rust does not form inside the fuel tanks and form scale that falls into the bottom of the tank that either gets stuck against the fuel filter sock clogging the fuel inlet to the fuel line, or gets into the fuel line gets up to the carburetor and clogs all the small fuel bleed circuits.

3) since the tank is not vented when the car is sitting the fuel cannot evaporate, and will take much longer to go bad if the car sits for years.

Basically the charcoal canister is the PCV of the fuel system. the function is similar. a PCV sucks the extra vapors from the valve covers and reduces oil varnish from forming it also creates a slight negative pressure inside the engine that stops small leaks of oil. the charocal canister is located in the air base, so there is an exchange of positive and negative air pressure as you drive, the pcv is located after the carb in the intake manifold so it will always see negative pressure.

so there is an emissions aspect to the charcoal canister, it reduced the millions of gallons of fuel lost as vapor to the atmosphere its introduction improved air quality just as a PCV did the same for oil leaks and clogged up engine oil. but the charcoal can also keeps your fuel system in better condition removing moisture build up and preventing rust formation inside the fuel system.

you can also buy an elbow for an aftermarket air filter base, drill a hole in the air cleaner body and pop a hose connector into it then you will have a pcv vent connection and a fuel vapor can connection. the pcv is a controlled vacuum leak so the vent for one valve cover gets fresh air through the air cleaner base, and the other side is connected to the pcv and goes to full manifold vacuum.

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H, this is a damn fine write up - well done - rep points coming

Don

Thanks for the info. I always wondered what this did. The one on my Mustang is not attached to anything as far as I can tell and nothing bad has never happened, so figured it was not a critcial component. The one on my Bricklin (ford engine) seemed to not be hooked up (no stock air cleaner) so I removed it to make room for the crusie control.

most people rip the stuff off. on a daily driver you can imagine stuff like that would make a big maintenance difference, most of our cars are garage kept now and we drive very little so the corrosion is controlled and very little occurs now. also over 40 years all the hoses and connections fall apart or parts get changed out and there is no way to reconnect the original parts so people just leave them vented and no harm done. Unless you ever flip your car over. if you flip your car over without that canister and the line is vented fuel will come pouring out of that pipe and you could start a major fire raging until the fuel tank blew up.

the sad thing is it could happen, friend of mine had a 71 vert, he was screwing around lost control in a turn, recovered hit the curb and the car went right over, crushing the windshield traping him inside the car, amazing he wasn't killed when the windshield collapsed on him. his drivers seat back broke and he ended up in the back seat... the engine was still running, trying to get his lap belt off. fuel was pouring out of the vent line and poof fire started. the car did not burn to the ground and he got out, but that aged him many years. car was sold for parts and he gives me the stink eye when i drive my mach 1. hee hee

the canister would of restricted the fuel pouring out of the vent and it would of been more contained inside the original air cleaner as it drained. instead he had a bottle rocket of fuel shooting upsidedown all over the engine bay spraying the hot exhaust manifolds, one spark is all you need.

had he plugged the vent tube and used a vented gas cap he would of been much safer as well, the fuel would of then leaked out the fuel filler neck and out the vent of the fuel cap from the rear of the car.

most people rip the stuff off. on a daily driver you can imagine stuff like that would make a big maintenance difference, most of our cars are garage kept now and we drive very little so the corrosion is controlled and very little occurs now. also over 40 years all the hoses and connections fall apart or parts get changed out and there is no way to reconnect the original parts so people just leave them vented and no harm done. Unless you ever flip your car over. if you flip your car over without that canister and the line is vented fuel will come pouring out of that pipe and you could start a major fire raging until the fuel tank blew up.

the sad thing is it could happen, friend of mine had a 71 vert, he was screwing around lost control in a turn, recovered hit the curb and the car went right over, crushing the windshield traping him inside the car, amazing he wasn't killed when the windshield collapsed on him. his drivers seat back broke and he ended up in the back seat... the engine was still running, trying to get his lap belt off. fuel was pouring out of the vent line and poof fire started. the car did not burn to the ground and he got out, but that aged him many years. car was sold for parts and he gives me the stink eye when i drive my mach 1. hee hee

the canister would of restricted the fuel pouring out of the vent and it would of been more contained inside the original air cleaner as it drained. instead he had a bottle rocket of fuel shooting upsidedown all over the engine bay spraying the hot exhaust manifolds, one spark is all you need.

had he plugged the vent tube and used a vented gas cap he would of been much safer as well, the fuel would of then leaked out the fuel filler neck and out the vent of the fuel cap from the rear of the car.

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Great post! Methinks Ford got it right the first time. If it calls for a

charcoal cannister you should use one. Fuel delivery is a serious

concern.

mike

Since no one mentioned the $10,000.00 fine for removing factory emission equipment....I will.

All this talk of the charcoal canister made me wonder what the P/O of my car did. Looks like he kept the gas line vent but capped the other line that went to the air cleaner.

Now having said that I noticed a couple of connections that I forgot about and was wondering if anyone can identify them for me.

Since no one mentioned the $10,000.00 fine for removing factory emission equipment....I will.

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Sounds like I'm in for $20K then.

Since no one mentioned the $10,000.00 fine for removing factory emission equipment....I will.

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Sounds like I'm in for $20K then.

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LOL

Since no one mentioned the $10,000.00 fine for removing factory emission equipment....I will.

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Well not quite that high don...but it is quite a big fine.

WARNING: Federal law makes it illegal for ANYONE to tamper with, disconnect, remove or otherwise render inoperative ANY emissions-related control device. The Environmental Protection Agency and most states have actually been rather lax about enforcing this rule on motorists, but they haven't hesitated to nail professional service facilities that have been guilty of tampering. Even so, the fines can be hefty. A violation may make you liable for up to a $2,500 fine!

No Tampering

The federal anti-tampering law does not, however, apply to race cars that are not operated on the street, other full-time off-road vehicles, show cars that are not street driven, or vehicles not factory equipped with emission controls (most 1967 and earlier vehicles). So that exempts all antique cars, and most classic cars and muscle cars.

The Clean Car Law (RCW 46.16A.060) requires vehicles across Washington State to be certified to California emission standards. Starting with 2009 models, vehicles must meet these strict clean air standards to be registered, leased, rented, licensed, or sold for use anywhere in Washington.

Types of vehicles that must meet Clean Car standards

•All new passenger cars, SUVs, vans, and pickup trucks with a model year of 2009 or newer must be certified to California emission standards. New vehicles that don’t meet California emission standards cannot be registered, leased, rented, licensed, or sold for use in Washington.

•Used vehicles must be certified to California emission standards if: ◦The vehicle is a 2009 or newer model.

◦The vehicle has less than 7,500 miles on the odometer.

◦The new owner is a Washington resident.

◦The vehicle isn’t exempt (see below).

So in washington state...long as you dont have a 2009 you dont have to pass cali emission's...But that is diffrent from state to state

those disconnected lines might of been for OEM electronic spark control.

some cars had them. I've only seen them once before. i think inside the dash would be a little box that is the brains of the controller then there would be a little solenoid control that would of been by the coil and distributor on the passenger side of the motor. that controlled a vacuum line and adjusted the distributor vacuum canister. some states required more emissions like cali and i think it was part of that, there would of also been a smog pump too i think.

I'm fuzzy on operation but i know the brains monitored the RPMS of the engine and it would add extra adjustment to the vacuum canister on the distributor to advance or retard spark and lower emissions, depending on engine load.

Getting into the smog pump era i intentionally stayed away from late 72-73 cars. when i researched smog pumps, i know at this point 90% of them don't work any more and there wasn't a way to rebuild them, i remember people gutting the smog pumps then putting them back on cars to get concourse points the unit was all show with nothing inside and the gases would just feed back to the intake i think.

The emissions enforcement is all over the place in the north east anything older then 25 years old just needs a safety inspection they don't even look under the hood or care. if you have 4 tires and they hold air your lights and horn works they pass you. in other states like Arizona, if you do not declare your car as antique(which forces a limitation of 2000 miles a year or you pay another fine(tax)) then you must pass the emissions test for the year of manufacture as a normal road vehicle or you can not get the car registered, they are insane at these state testing places in AZ a lot of people drive out into the wastes away from the cities to find places that will pass them. If your in Phoenix and you have to go for emissions if your car was a Cali car with a V2 carb, and you show up with a V4 carb they instantly fail you. you have to keep the original equipment for testing after that they don't care. I lived in tucson and it was hell back in the 1990s you had to keep all the original bolt on equipment for your car before test day you scrambled around the car to put the original carb and emissions equipment back on. then we used to lean the hell out of the carbs, the cars would barely run right and we would add tons of fuel cleaner to the fuel tank and retard the timing way back till the engine was on the verge of overheating. because they would test emissions at Idle on the older cars. so you wanted the exhaust manifolds freaking Cherry red and the intake super lean just to pass CO2 and NOX then you limped a block away from the testing place and brought everything super rich again. Limped home and replaced all the original parts for your performance parts or just better parts then what was all worn out after 20 years at the time. urg it wasn't fun.

in 1991 i bought a 50$ 1970 oldsmobile off a Indian just because i needed a car asap. i could put my hand through the sheetmetal it was so rusted out, but the big concern was arguing with the emissions official that the correct 2 barrel carb was on the 350 engine. the bumpers were held on with rope that was nothing compared to passing emissions hahahaha. I passed.

All this talk of the charcoal canister made me wonder what the P/O of my car did. Looks like he kept the gas line vent but capped the other line that went to the air cleaner.

Now having said that I noticed a couple of connections that I forgot about and was wondering if anyone can identify them for me.

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Just removed the canister from my car and was ready to throw it in the garbage when I figured I'd see if it had any actual use. Thanks to 72HCODE for the great write up. I will be cleaning it up and putting back where it belongs. So much useful info on this site, thanks too all who contribute

Is the charcoal canister necessary? It has been there since the car was new I am sure, and not even sure it is functional any more.

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I would leave it on there unless you want a fuel smell coming from under the hood. Now if your fuel vent on the top of the tank is clogged up then the canister becomes useless.

By the time our Mustangs came to market, the government was having the car companies lower their emissions. One of those is hydrocarbons (think gas fumes). To help keep the hydrocarbons down the gas tank was no longer vented to the atmosphere. Then (as today) the fuel tank "breaths" through the charcoal canister. As the heat of the day warms the gas in the tank the hydrocarbon vapors from the expanding liquid fuel are captured by the canister and held there by the charcoal to be released to the engine when it is running. So this doesn't really cost you horsepower other than the weight of the system but it does save you money by keeping that expensive gas you are paying for from going into the atmosphere. Also, if you are messing around with that vapor system you could also create a fire hazard.