When the beep goes steady the engine goes into safe mode. It will limit power to protect the engine.
You may have a problem that many of us have had when changing the pumps. Try this: when you start the cold engine, wait until oil pressure builds and then rev to 1500-1800 RPM until you hear an audible difference in exhaust tone (you can also just check for water flow). If that does not establish a good flow or you continue to have the problem you may have to have it checked by a pro.