Hello everyone,
I've recently partially desmogged my 1987 22r, and I decided to leave the double charcoal canister system in order to properly vent the gas tank. In removing the stock carburetor however I had to remove the hose running from the lower (final?) charcoal canister to the carb, leaving that larger port on the canister open. Here are some potentially helpfully images of my setup (taken from another reason, and don't display the lower charcoal canister)










My current setup is kinda stinky, so I'm wondering if I can run a hose from that lower canister to the air filter on the carb (I have an extra hole in it) in order to burn off those stinky fuel fumes. Would the resulting vacuum be to much for the EVAP system or would that VSVS valve handle it?

Also, in the third image (assuming these images show up) there's a device with a gold top just bellow where the radiator hose connects to the intake manifold. I pulled the resonator off of it and left it open as I don't really know what it is. What is it, and what should I do with it?

Let me know if yall have any insight,
Thanks!
-Jackson

 

Bumperoo, anybody?

 

Help me, please, somebody.

 

Why leave the canister? I removed it on my 87 22r, plugged the line coming from the tank and eliminated the return line from the fuel pump. I read that the canisters get plugged up and cause problems so out it went. Runs great.

 

Doesn't the tank require some sort of vapor purge? There's definitely a reason why gas tanks aren't just plugged to begin with.

 

a vented gas cap. i did the emission removal on both mine.

 

Doesn't work that way. The vented gas cap only allows air IN, to keep the fuel pump from crushing the tank. But when it gets warm, the fuel turns to vapor and the CAP won't let it get out. The vapor goes out through the vapor canister, which holds it until the engine sucks it out and burns the vapor as fuel.

If you don't have some connection to the vapor canister or replacement (if you've just plugged the fuel return line), then you have a leak in your system (or will soon, as the vapor pressure will create one).

 

Yeah, this is my understanding. So given this, could I route the final canister back to the air filter, burning it off? Or would the carburetors vacuum be too strong or varied? (the vacuum will vary via throttle)

 

I'm only 62, so carburetors are before my time.

But I suspect your canister works the same as others. Hooking up the output line to the air cleaner should work fine. Varying vacuum doesn't matter; it just has to "eventually" pull out the vapors. The EFI versions have a thermal vacuum valve which closes off the vacuum when cold, to improve drivability. If you don't have such an expensive valve, be prepared for a little trouble keeping it running when cold. (or not; some on this site report bypassing the TVV without issue).

 

Hmm, I don't think I have a thermal vacuum valve, just the VSV that both canisters are hooked up to. I'll give it a shot and see how it works. Does anyone know what the VSV is/how it works?

 

what Chaser said...vented gas cap. Been running mine like that for many years. No leaks or blown up tank as stated above.

 

I blocked off my OVCV (float bowl vent) and have the tank venting off the hardline that comes up on top of the passenger fender. No evap canisters or VSVs left. Probably the wrong way to do it but no death and dismemberment yet.

 

Yeah, the tank definitely needs a vent, I'd just love to find a way to deal with the fumes.

 

Thermal vacuum valve: So does my 87 carbed truck but its a california model. The air cleaner hook up sounds best.

 

Where is your TVV in your setup/what's it look like? I think I'm going to simply run a vacuum line (possibly with a filter) from the lower canister to the hole on the bottom of my weber air filter. I'll let you know how ot works, and will possibly do a little write up on it.

 

Hey Sweitzer, did this end up working out for you? I just stuck a weber in and would like to keep the charcoal as well but I don't want to vent to atmosphere.

Also, what did you do with the PAIR system/reed valve and air pump? I capped the little vac lines on the PAIR but the big hoses are just hangin out there... everyone says 'just cap it off' but I'm not sure they make vacuum caps that big lol

 

FWIW (88 fed 22r) I yanked both canisters and have never smelled gas fumes even with my head in the engine bay.

I believe the stock system connects both charcoal canisters to manifold vacuum once the engine gets up to temp. It's using a green "temp switch" by the thermostat, and a VSV on the fender.

My PAIR valve is just hanging out above the oil filter, with all the stupid hoses gone. Air pump was removed, but the bracket is still on since it bolts through the motor mount.

 

Interesting. I left the green temp switch in, and the charcoal is still hooked up to its VSV; however I capped the top VSV port that used to run to that little tree of vacuum nipples (also capped off) so its likely not working anyways. When you pulled your canisters was your tank empty, and how did you block the fuel lines? Worried about gas gushing out of the hard lines.

Thanks a bunch. Been reading pages and pages of desmog stuff but there are always little things you run into when actually doing it yourself

 

The vent for the tank is a hardline that runs to the passenger fender well (with the other fuel lines) and then a hose goes to the canister. I took the hose off that hardline and have never seen or smelled gas coming from it. It's ugly but has worked so far.

Here's the best pic I have (huge resolution)

https://i.imgur.com/WFBKOnE.jpg

 

Awesome, that helps a lot. Thanks!