I won't be of much help but a couple questions: What is Auto and Service? Not familiar with that filter. Also, what did you take apart 2-3 times? Filter or pump? Could there be a blockage on the pressure side? If there is then the pump may or may not prime, depending on how much water flow is initially achieved. Keep in mind these self priming pumps can only pull a little vacuum to start water flow. If anything such as too high of a lift on the suction side or a blockage on the pressure side then it may have trouble priming. Any way to disconnect the pump outlet from the system and see if it primes and pumps water ? Best I can do for now.
Al