So, is your solution pump actually stopping, or do you just have a pressure drop in the line after the solution pump.

I'll ask dumb questions....I assume you have nozzles of some type in the nozzle bodies?

Do you have the T-jet type quick-change rotatable nozzle bodies? If so, can you shut all nozzles to the OFF position except one per boom segment, then turn your valves on again & look for results?

Are you sure the solution pump itself is running fast enough? What method do you have on the tractor hydraulics to control the hydraulic flow to the pump motor?

Seems to me that if it runs at all, you should be able to maintain some type of pressure unless you have NO nozzles (tips) at all in the nozzle bodies.

Report back if you can. Good luck