Someone recently posted about a mock orange not blooming. Both of these are plants that are notorious for failing to bloom for some of the same reasons. You didn't tell us much about the conditions it's in, age etc, but here's some things off the top of my head:
*how old is the vine? wisteria can take between three and seven years to get established enough to bloom (10 -15 years if grown from seed)
*is it in full sun? Lots of plants that like full sun will grow and look thriving in less, but won't bloom
*pruning - wisteria requires regular pruning to keep it from getting totally out of control and taking over your yard, but if you are pruning off the flower bearing spurs, you can cut down the blooming.
*how is it fertilized? Is it in, or next to a lawn? Lawn fertilizer can run off and it is usually high in nitrogen. Nitrogen tends to encourage foliage growth at the expense of flowering (for lawn grass we want leaves not flowers). If you think high nitrogen fertilizer could be the problem, balance this out by giving it high phosphate fertilizer in the fall or early spring.
*it likes rich moist but well drained soil
If none of these seem to be the problem, one thing I have seen recommended a number of places is root pruning - just plunge your shovel a foot or so down into the soil a bunch of places around the plant at a distance of a couple feet away from the trunk. This severs some of the outer roots and can shock the plant into blooming. You would do this in late fall, to prepare it to bloom next year.
Part of the message is that plants tend to reproduce more when times are tough to be sure if they don't survive, a next generation will. If you make times too easy, they relax and just grow...
Let us know a bit more about the conditions yours is in and if any of this seems like it might be the problem.