Did you ever get this problem resolved? It seems as if both of us are having trouble eliminating the positive pressure. I have the intake off one last time, and I'm replacing a lot of stuff. If it still smokes after all this work, she's getting put up for sale because I am tired of wasting my weekends on this.

 

What alot of people don't understand either is on turbo cars you only have negative crankcase pressure till the turbo kicks in. When the turbo kicks in the vaccum turns into pressure.

 

Which is odd, because I only have the smoke at idle. The little vacuum hose is the one that is supposed to put vacuum on the PCV by being connected to the intake manifold though a small nipple on the side, and I am thinking that maybe as the engine wears and blowby increases that this small hose cannot handle the amount of pressure being created. I was thinking that it may be possible by increasing the diameter of the hose to increase the vacuum being put on the PCV at idle. The only thing is the plastic nipple down at the turbo intake is really small, but I was also thinking that a T could be placed in the larger vacuum line which goes into the oil trap and hook that T up to the new larger line going to the intake. Anybody think this could work?

 

Oh...sorry I forgot to update this thread. Well I ended up having to replace the EGR valve,problem solved!!! It had alot of gunk when I took it off and cleaned it and I guess either the clean job or the valve was defective to begin with. My indie mechanic who has long experience with these volvos was nice enough to check out for me. He also told me that volvo aventually did away with the egr valve for several reasons one of which the valve sometimes caused the positive back pressure which a novice assumes it is the PCV system...sometimes doesn't throw a code or cause irradic idle. Anyway, mine needed to be replaced and the valve fixed the problem.

Thanks again everyone.

 

That makes sense. I wonder if it is possible to just block off the valve. I know on Mercedes diesels that is one of the first things to do when you buy one so that all the grease doesn't gunk up the intake. I suppose I could fill the hole going into the intake, should have left the carbon in it!

 

If you just plug the hole and remove the valve you will always have a check engine light on though.

 

What about just plugging the whole and leaving the EGR in place? Basically that's how it was before I cleaned it, and the light never came on. I'm thinking I could also plug the vac line with no effect on the light. Is there a way to check and clean an EGR? I sprayed carb cleaner in it, but I can't even get the valve off the pipe in order to drain the cleaner out. I undid the nut that I thought was holding it on, but it would not budge off that pipe. I could rotate it, but not pull it off.

 

Sometimes it is a real pain to get the pipe out.
What I do is with the intake still in place I loosen the nut and then tap the pipe with a hammer and srewdriver to pop it loose.
Eventually a code will set for EGR flow to low if you just put a block off plate in there.

If you eventually plan on doing a ECU upgrade I would get the one with the EGR delete.