I have no idea but I have a complete PS set-up (rack, pump, lines) I could send you for a low price. I'm converting to manual and the PS worked fine before.
A few possibilities: . Did you put the same pulley from the original pump? if not compare them. Sometimes pulleys get mixed up , i.e. water pump and power steering aren't the same. Other thing could be that it's the wrong pump. Or when you changed them some dirt got in the rack.
Does the pump make noises at all during operation? What about the fluid -- have you purged it by loosening the return hose and turning the rack lock-to-lock with the engine running? Did the fluid contain bits of metal when you replaced it? Clear or grimy?I had a bad PS pump on my 318 that whined like crazy just before it stopped working. Ended up replacing the pump, hoses and all the seals on the rack and steering has been dreamy since.
Repeat once more and then fill with new fluid.At this point you'll know that only fresh fluid is in the system.