I dont know where you live, but most codes that I deal with limit the use of Studor vents, they will go bad. If they do they will let the sewer smell into the dwelling, that would be my guess. I think that you have to check with your local code office and find out if this is a legal hook-up. If you used a contractor, it's their prob. to solve. Luck.

I also have the same problem.There is a nasty smell coming out of my sink. Im worried I am going to get sick from this?Do you think this is a health issue??