Finally found where my second vent pipe exits the house. The first vent pipe that services the upstairs bathroom and kitchen seem to work fine. The 4" vent pipe runs from the basement (in the area of the sewer discharge line) up about 6' then makes a 90 turn and exits the house (about 2' above the level of the lawn). The vent pipe is just an opening on the side of the house facing east. Dosen't this vent pipe need to extend out of the house somewhat and upwards? Could this be why we may be getting some blockage and a foul odor in the basement. I also want a plumber to do a smoke test on the pipe to see if there is a hole in it and clean it out seeing that there is nothing to prevent debris or an animal from getting into it. We moved into this house a few months ago so just learning about all the surprises. Any help would be appreciated.