I took off from San Diego once and the outflow valve in the 737 went full closed as we were saturated with clearance info so opened up the outflow valve fully to comply with ATC instructions with turn and altitude changes. since we were taking off to the east. Finally when we had time we used manual pressurization to complete our flight. My FO just looked at the ceiling so lost him for a few minutes. If you are below 10,000 ft just shut pressurization down and aviate.