LOL. I think there's your answr EricHanson. I was gonna say you may be coming on too strong and you didn't list in your OP how you look for their responses or cues - it seems like you are "throwing everything you have at them". And that's terrifying/annoying/incomprehensible for shy people regardless of their type. As an 'E' I can still be very private about certain topics or get moody and get very cautious in certain environments and people trying to pry information out of me or being 'pushy' makes alarm bells go off and I withdraw even harder/avoid.
There are really basic and time tested books and articles about 'how to win friends and influence people' (lol) but the basics apply regardless of the 'type' of person you are talking to. Find something they want to talk about or are interested in and engage them. A lot of times genuine interest and friendliness goes a long way.
Also, introverts do not respond in the same way as extroverts - you are probably looking for more obvious extravert responses like smiling widely, laughing, verbal agreements, lots of talking -- you don't need nor should you expect these responses from a shy person. You're not necessarily trying to turn the person in front of you into an extravert or you (...or are you? LOL?)
They may actually like what you are saying or be interested in you but you just dont' realize it because you're looking for them to respond to you the way you think you'd respond to someone if interested.
Also, matching people's wave lengths goes a long way. I personally try to monitor my energy levels and presentation to not overwhelm or be too out of step - sometimes of course being naturally E and spastic this is hard. On the flip, you can't totally try to be like the person in front of you, there is nothing wrong with being more chatty or energetic or perkier than the person you are talking to, you also want to show peopel what you are about and not fake it. There are people who are always themselves regardless of the social situation and they do fine socially, self-assurance also goes a long way.
PS "self-assurance" and "pushy" are not the same thing.

In fact, being at ease with yourself often puts others at ease. The fact you seem like you are trying so hard to get something from the introvert probably puts them on the defensive. If you are more on the mind set of trying to have a good time or genuine interest in the person in front of you it goes a long way to paving the way.
PPS Maybe you can start a thread on grooming your tert Fe. Fe can successfully break down social doors much better than Te/Ne.