How long have you had the Campsis? It takes about three years for it to establisha strong woody framework of branches before plants begin to flower well?

The problem might be lack of strong sun where you are - they flower best in areas where they can bake a bit in hot, bright sun for a few hours a day. Otherwise, do you prune and if so, when? The time to prune these (assuming its in the ground) is around early March, when you can cut them back quite hard - pruning at other times might mean you lose any possible flowers. Too much high nitrogen fertilizer too often can cause lack of flowering too.

The Campsis is three years in the ground and one year in a large pot before I planted it. It gets a lot of sun for most of the day. I prune it in late Feb early March each year. It flowered in the pot but refuses to flower now that it is planted out. I'll give it another year and if it does nothing i'll replace it with a Clematis which do very well on the same fence.

Oh, okay, so maybe you'll get flowers next year, its obviously been concentrating on expanding its root system since its been put in the ground, Otherwise, you're doing everything right...