Charcoal Canister (1 Viewer)

[gcrump01]

1980 FJ40 - Ok, I've read the a bunch of desmog stuff on here - some say cap the lines to charcoal canister, some say remove the whole canister, some keep it, etc. The more I read, the more confused I get. Question is with Trollhole carb what do I hook the line in the pics to if I remove the smog stuff it was plugged into?


I assume that line is there to deliver excess fuel or fumes back to the canister?

 

[kruisinkid]

are you doing a full desmog? if so, with a THC, remove the circled line.

 

[gcrump01]

Yes, full desmog with Trollhole carb. If I remove the line, I assume I should plug that port on top of the canister and leave all other canister lines as they were originally, right?

 

[kruisinkid]

when i did mine last fall, i bought a new charc can with only tank and purge ports from autozone. marshall said to hook the hose running from the evap separator to the purge port and i left the tank port open. all seems to work fine. i kinda wish i had a vacuum to suck vapors through the can into the air cleaner, just before the carb. i bought parts to actually plumb it but havent yet, perhaps never will.

 

[scrapdaddy]

Kruisinkid,


On your new charcoal canister from Autozone, do you have part number, etc. to ask for.


Thanks,

 

[1973Guppie]

check the 80's section, there is a charcoal canister a bunch of guys are using, it's cheap, like 60 bones, and available at the local parts store. Just hook one line to the tank vent and the other to the intake manifold vacuum. The canister should have the ports marked. Easy peasy lemon squeezy.

 

[kruisinkid]

autozone p/n VC120
$36. super cheap. have at it.
EDIT: it wont fit in the old bracket. you will need to fab something. i used silicone cushioned loop clamps from mcmaster.

 

[Fast Eddy]

1980 FJ40 - Ok, I've read the a bunch of desmog stuff on here - some say cap the lines to charcoal canister, some say remove the whole canister, some keep it, etc.

I assume that line is there to deliver excess fuel or fumes back to the canister?

As far as I know that line is where fumes are sucked out of the canister into a vacuum source. No?

are you doing a full desmog? if so, with a THC, remove the circled line.

More details please. What does the carb have to do with it?

A "full desmog" should never result in removing the charcoal canister or you'll end up with a cloud of gas fumes around your rig forever after. F' that.

To the OP: Keep the evap system. No question.

 

[scrapdaddy]

Thanks Guys,


I'm trying to figure my evap system with a 50 gal tank and a 5.3 vortec, in my 55. I guess you need some vacuum in order to pull the fumes trough the canister.

 

[gcrump01]

Fast Eddy,

you are probably right that the line is where fumes are sucked out of the canister. I was just guessing that it went the other way, excess fumes coming from the exhaust & smog stuff, going into the canister. I'm not a mechanic & a newbie with FJ40s for sure. So where does that line attach on the drivers side of the engine bay if I remove the smog stuff? Some place on the manifolds, maybe? I don't see any other options to attach that line.

Not sure the carb has anything to do with it - just figured that would be one of the first questions I got back.

I do plan to keep the canister & the evaporator system including all the lines under the tub.

 

[1973Guppie]

the charcoal canister basically is just a fumes storage area, pressure changes in the tank cause fumes to be pushed out, this way they are burnt and not vented to the atmosphere. If you are desmog you can simply vent to the atmosphere but personally I think it is a cleaner solution to use a new charcoal canister.

 

[kruisinkid]

Greg,
There is no where to attach the line that comes OUT of the canister if you do a full desmog. The evap system technically is not part of the emissions/smog system, but you will see the EVAP system in the emissions FSM. Marshalls fix when using his carbs, and thus having to do a full desmog, is to let the fumes vent through the canister to atmosphere. BUT!! You have to move the hose coming from the vapor sep from the 'tank' port to 'purge' port on the canister to defeat the internal check valves.

 

[Fast Eddy]

There is no where to attach the line that comes OUT of the canister if you do a full desmog. The evap system technically is not part of the emissions/smog system, but you will see the EVAP system in the emissions FSM. Marshalls fix when using his carbs, and thus having to do a full desmog, is to let the fumes vent through the canister to atmosphere. BUT!! You have to move the hose coming from the vapor sep from the 'tank' port to 'purge' port on the canister to defeat the internal check valves.

Sorry, but this is terrible advice and rife with errors. The evap system is part of the emissions/smog system. If you do a full desmog there are still places to attach the output of the charcoal can. Letting fumes vent to the atmosphere is wrong in so many way. The check valves can work to your advantage.

Just run the evap as normal and take the purge side of the charcoal can and run it to a vacuum port, or at least to a port on the air cleaner.

If you are desmogging, and you still have BVSVs filling holes in the thermostat housing, it is a very clean solution to run the purge side through a BVSV so that the evap system is normally closed off to the atmosphere when the rig is parked. If you desmog, there should be several manifold vacuum ports available to purge the evap system.

 

[kruisinkid]

well you'll have to take it up with marshall. thats the advice i got from him. the point of putting the line from the vapor separator to the purge port is so that the fumes go into the canister and dont come out, because of the way the check valves INTERNAL of the canister work. so my setup is not really venting to atmosphere.

 

[Fast Eddy]

There has to be some motivating force for fumes to move around. Just having the can connected to the tank won't do much. I can imagine that in your setup expansion within the tank could push fumes through the charcoal, but then the tank would get negative pressure due to check valves not allowing air back in.

The connection to vacuum sucks all the fumes from the tank when the engine is running and allows only a little circulation, through the charcoal, when the engine is not running.

 

[kruisinkid]

i agree with you on all of that eddy. it SHOULD probably be connected to vacuum (not necessarily manifold, could create a large vac leak i would think), but does not NEED to be, and in my case, works just fine letting the charcoal absorb fumes that have been PUSHED out of the gas tank through the vapor separator, into the charc can. like i said in my earlier post, i bought parts awhile ago to plumb into the air cleaner just before the carb throat to suck the excess fumes back into the system to be put to good use. havent, and may never, get that done.

 

[scrapdaddy]

This has been a good discussion. Learning a lot.

 

[PabloCruise]

Thanks Guys,


I'm trying to figure my evap system with a 50 gal tank and a 5.3 vortec, in my 55. I guess you need some vacuum in order to pull the fumes trough the canister.

Ron, Is your 50 gal tank have the same 4 vents that the stock tank did?
If yes, I'd keep the factor separator, make sure the check valve is not cracked, and then plumb the charcoal can purge line into manifold vacuum, so when vac is highest (coasting) it will aspirate the vapors from the can.

 

[PabloCruise]

Sorry, but this is terrible advice and rife with errors. The evap system is part of the emissions/smog system. If you do a full desmog there are still places to attach the output of the charcoal can. Letting fumes vent to the atmosphere is wrong in so many way. The check valves can work to your advantage.

Just run the evap as normal and take the purge side of the charcoal can and run it to a vacuum port, or at least to a port on the air cleaner.

If you are desmogging, and you still have BVSVs filling holes in the thermostat housing, it is a very clean solution to run the purge side through a BVSV so that the evap system is normally closed off to the atmosphere when the rig is parked. If you desmog, there should be several manifold vacuum ports available to purge the evap system.

All this. In a hot climate the vapors will fill the can and eventually come out the port on the bottom that is open to the atmosphere. Then your rig will stink bad!

 

[scrapdaddy]

Pablo,


Yes, mine has all the vents. I need to find the different vacuum ports on the 5.3. I'll need the one for the brake booster. After reading all this, I guess running the line to the air cleaner canister isn't the best idea.


Thanks guys and didn't mean to hijack the thread.