David,The pump cannot return more fluid than it takes out. It may be pumping air through a supply side leak and returning that.Good Luck and let us know what you find.
Blowing oil out the power steering pump is a classic indication that you are sucking air in the system, and if it goes away after it warms up, the seal has warmed up and started working. Bypass the power steering ram and see if the same problem happens, if so, it is your pump.--Geoff