I experienced something similar. We had a website with several products that seemed fairly similar, so we were concerned that people might have trouble deciding which one to get, and not buy as a result.

So we made a product advisor applet where the user would answer a few questions and it would suggest one or two products that would be best for them. Getting the applet right took a bit of work, but once it was done it worked very well.

We put it live on the site and.... conversions dropped precipitously. We A/B tested it and yep, it definitely hurt conversions. I still don't know why it hurt conversions, but it did. So we moved it from the homepage to a FAQ section of the site, and hardly anyone ever used it at all.