Charcoal Canister Experiment

[70spider]

Well, my daughter's complaints about the fumes got me to thinking about the disconnected charcoal canister (by the PO). I went through the manuals to see how it hooks up. So this is what I came up with:

The "open" tube thingy I think is supose to be connected somehow to the exhaust manifold. However there is no provision on my current exhaust manifold to attach it.


The result of connecting the upper canister hose to the intake manifold did some crazy stuff to my idle, it went from ~850 rpm to 1500 rpm and became "lumpy", for a lack of a better term.
I adjusted the Idle speed screw out as far as possible and little change, about 1300 rpm. I then adjusted the air-fuel mixture screw, I backed it out until the idle smoothed out, this decressed the idle to 1000 rpms. This is as low as I can get with the carb.
Any suggestions?
Also there is a distinct vacum noise now.

[70spider]

Update Instead of posting a new topic I resurected this one that got no replies with what happened today when I hooked up the charcoal canister.

[bradartigue]

In case anyone wants to do this -

The old metal barrel, two-port type canisters had the top port to the carburetor suction (small) and the mid port to the carburetor vent (big). The bottom port was open and aligned towards the exhaust manifold. Some cars IIRC had a short hose on the thing that extended it to the manifold somewhat, it was also wide open. Heat from the exhaust warmed the thing and made it function. With the car off the vapors are drawn into the charcoal. When you started the car the vapors were sucked back into the carburetor. A three-port variant (and some two-ports) would have a check valve in the trunk and be connected as well. But truthfully this was a half-assed system and if you've been around old cars long enough they just kind of stink. If you have a raw gas smell something simply isn't right, usually the fuel tank vent line is left open in the engine compartment; cap it.

The plastic type was a partially sealed system. The top port went to the carburetor mid section. The bottom port facing the firewall went to the carb vent. The bottom port facing the grille went to the fuel tank vapor return port. The cap on top is calibrated but not adjustable, maintaining a steady stream of air into the system. Without the cap you have an unmetered air leak, particularly in FI cars, and it causes poor idling.

Virtually any modern replacement charcoal canister can be adapted to do these jobs, and they work well.

[70spider]

Thanks Brad.

[So Cal Mark]

charcoal cannisters need a fresh air source into the cannister, otherwise the charcoal never gets purged of fuel vapors

[majicwrench]

Also the vast majority of them use a ported vacuum source, or some sort of soleniod so they are not sucking fumes at an idle. Many cars they will not suck fumes when engine cold either.
If it changes your idle, something is not correct.

Like was said above, if you have constant smell, likely something else is wrong.