BMW Z4 windshield washer

I should add they do work if the car is stopped and sitting with the engine running or the engine off. Once the car starts moving a small amount of fluid will come out and then stops. I cannot hear if the pump is running while driving. I have removed the pumps to check to see if there is something floating around in the tank but I see nothing. The washer for the head lights works the same way as the windshield. This is a drop top so not rear window washer. Thank you for any help.