Thank God!!! I am vary happy to hear that your determination has finally paid off.Jack Rock wrote:It PASSED! Finally. A combination of two things, first, my original Volvo cat was definitely shot which was replaced by a muffler specialist with a inadequate aftermarket cat the size of a large coffee. That was replaced with a very used Volvo cat which fixed my NOX readings immediately. Next, my Volvo specialist replaced all sensors and plugs etc with OEM parts from a donor which made no difference. He removed the EVAP line from the manifold and capped it which made it pass. We haven't gone into diagnosing what exactly is wrong but I think it could only be the purge valve. At one point early in the saga I had removed and cleaned the purge valve - it was definetly stuck open, even so, never would I think that there are enough vapours to make the car fail emissions so bad. The attachment indicates that the canister gets emptied at the appropriate time, this leads me to think that as long as all the lines and the canister itself are in good shape that only leaves the valve. I guess what I'm trying to say is, can the charcoal in the canister get saturated or can the canister become non functional?
With aftermarket Cat's, I steer clear of anything that uses the word "universal". Even if they work when first installed, they won't by the time your next e-test is due, they're just useless. For future reference, if you have to go aftermarket, always go with a 'direct fit' cat.
As far as the purge valve goes, it will have a huge effect on emission if it's stuck open, the computer will cut fuel as much as possible and still have a rich condition. If the valve is stuck open I wouldn’t go any further, just replace it and you should be good. I would have suggested checking the valve in my last post but I honestly thought we had eliminated that earlier. Now a canister can get saturated, and if it does it's done and will need replacement, basically there should be no liquid fuel within the canister, if there is it's toast.
Also on that note, here's a little tech tip many people are unaware of.
When the pump at the gas station stops while filling the top portion of the tank, you need to stop!
Many saturated canisters are due to excessive filling of the tank forcing raw fuel into the evap system. While it's true there is room for up to 5 litres or so above the filler neck opening in the top of the tank, that area is needed for fuel expansion.
Anyways it's a good thing you finally got this thing to a mechanic who is comfortable and competent with Volvo's