q-jet problem

i put a brand new quadrajet on my g30 and it won't take fuel when the secondary opens. I have 14 psi fuel pressure while coasting, and it dips down to 10psi under acceleration, but then rises back up to 14 and the motor bogs down and backfires. It seems as though it can't take fuel when the secondary is open.

10-14 psi is really high fuel pressure for a Q-jet. Usually 5-9 psi is normal. (per my Haynes manual)

Excessive fuel pressure may mean the needle and seat are unable to shut off the fuel flow when required, resulting in a over-rich condition.

However, your problem is not related IMO.
I suspect the secondary metering rods are not adjusted properly or are disconnected.
These rods are lifted up off their seats when the secondary air doors (not the secondary throttle blades) are opened.

IMO whoever rebuilt the carb made a mistake