I've got zukes in the garden, zone 3, and have harvested about 7 this year but production is picking up now. The plants are wimpy? How wimpy? Are they stunted? Pics with scale? I've no idea if it's the weather, your soil or what that's causing the situation, but if they're as big as they should be and just not fruiting, then yeah a soil test and correction with the appropriate nutrients, probably non-organic unless you can get ahold of a liquid compost tea would be your best bet to kick start them into fruiting. Make sure the females aren't shrivelling up under your nose from lack of pollination. However, if the plants are stunted or just not growing then perhaps the prognosis is less optimistic for the rest of the season, depending on where you live and the length of your growing season, how hot it gets where you are, etc. Hot weather (high 80's-90's) consistently can harm production. If the soil was tilled well enough, loosened up so it's not packed so hard that the roots don't have room to grow, then you should be able to fix your problem if the plants are growing, just not fruiting... but your yield will obviously be hindered as some of us have already harvested a few fruits by now.

I've heard that in most new construction, the soil is highly compacted (and sometimes filled with crappy soil)
I would start fresh with a couple loads of compost, even some topsoil for regular landscaping.
Get a tiller and load up the compost from the dump (or a landscaping place)
You might want to terrace and/or do raised beds in the hilly area.
But for your current situation, can you find someone who has compost tea? (something you might consider starting, a compost pile!) I just found a place that gives it away (2 gal, able to dilute it up to 10 gal!) To buy the stuff is quite expensive, but if you can find a source......Nancy Good luck and happy gardening!