I failed emissions a second time, so I took my 93 to a local shop to have them smoke test it. First, they said all the PCV hoses were shot (not a huge surprise to me), and second, that the entire charcoal canister was shot as well. The main tech said there was stuff just rattling around in it ("like charcoal?" I said) and that a replacement is $$$.

Yesterday my Bentley arrived, so I got the car back today without them doing anything and started testing everything I could. I started with the CC lines. I pulled each line, plugged one end and vacuum tested it with my MityVac. Both the fuel tank line and upper valve line (the skinny one) tested fine. The fat lower valve line wouldn't hold a vacuum, so I tested a spare line I'd pulled at the JY just for some hose. Same deal, my spare was leaky as well. So I cut the hard end of the line off (the end at the manifold), and voila, it holds a vacuum now!

Progressing on to the actual CC, I pulled it and brought it to my bench. There is nothing rattling around it ;) I attempted to follow the Bentley test procedures, but on the first step "Plug the vent at the bottom of the canister", I hit a snag. My CC has a central nipple on the bottom, as well as two other holes around the circumference of the bottom. I don't know how I could seal this.

Well, if I couldn't do the first step because I couldn't plug the vent, then at least I could do the second. Bentley says to pull a vacuum off the *lower* valve port, and blowing through the fuel tank line you should get air out of the top valve port. Well, I couldn't even pull a vacuum on the lower port, but I could pull one on the upper port. Even then, I got no air through it (venting out the bottom).

So I pulled the valve apart (it just snaps together) and my suspicions were confirmed. The upper vac port controls the purge valve. What was also interesting was that the lower port has a very small bleed hole to the canister, so it's never completely sealed off. The purge valve connects it to a much large vent port, but regardless, you'll never pull a vacuum on the lower port because of the bleed hole.

FWIW, my recommendation for the charcoal canister would be to inspect it to make sure it's not split and leaking charcoal, then test that the upper port holds a vacuum. If that's good, blow some very low pressure air through the tank port and lower port to make sure they're not plugged up. That's it. The Bentley procedure is bogus and will fail every CC that gets tested using it AFAICT. And if you do have a problem with it, take the valve apart, clean it and test it again. Else just get one from the JY, unless it's completely ruptured, there isn't much to the vapor canister so I'm not sure why Volvo is charging $200+ for a new one.

Z
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93 240 170k, 97 850GLT 165k