Evap Valve Keeps Going Bad

[True Swede]

Hi

I have been battling this da?n emission system ever since I bought the car two years ago. The first year I spent close to $1000 to get the car through the inspection here in TX. That included the evap valve (changed twice), charcoal cannister, shut off calve and some other stuff. The car passed but the CEL came back within a month. I decided to keep driving and when it was due for inspection the following year I took the chance and figured if I got caught I would simply pay the fine. Well of course I got pulled over eventually, on my way to the airport to go to Europe on top of that, and given a ticket. When I got back I took it to a shop and after a couple of tries they had isolated the problem to the evap showing a resistance of 3 ohm. Had that replaced with OEM parts and it passed the inspection. Now about a month later that freaking CEL came back again. Pulled the code and it's P455. I can almost bet my life that it's the evap valve gone bad again.

My question is, is there something specific on the car that is known to cause this evap to go bad so many times? The car passed a smoke test and the gas cap also passed the test.

Car is -98 S70 T5.

TS

[Mike 97 850 GLT]

It shouldn't fail that often. On our '97, there's a filter between the cannister and the purge valve to keep crap from clogging or sticking the valve open. See if you have the filter in the hose going towards the cannister.

[backfoot100]

I've spent the last couple weeks battling the same CEL. I would clear it and it would be back in two days religiously. I replaced the purge valve, checked the hoses on the charcoal canister, replaced the hoses on the rollover valve and was getting nowhere. I replaced all my vacuum lines two years ago with silicone so I knew that they are good.

Today, I pulled off the two check valves coming off the purge valve. There is a tee connection next to the purge valve and one line runs through a check valve to the intake tube and the other line runs through a check valve to the intake manifold. The one to the intake manifold was bad. I could blow really easy through both ends. The other check valve was just one way like it's supposed to be.

I won't know for couple days if it really fixes it, but I have a really good feeling about it. At least it's the first time I've been able to actually find a problem instead of just shotgunning one part after the next and hoping that fixes it. Check it out and let us know what you find.