dirty pat

My 1981 Subaru GL Wagon 1.8L 2wd stopped running all of a sudden. After some diag work I found that I had spark to the plugs but no fuel to the carb. I put 12 volts to the pump and it turned on. After going to a Subaru dealer and getting what limited info they had on the car I tested the fuel pump circuit and found I was not getting voltage to the pump and there is 600 ohms resistance in the circuit. I was unable to locate a pump relay so I wired a switch to the pump to turn it on manually. Now I am getting less mpg than I was prior to the problem. Is the fuel pump turned on and off to get optimal mpg's? Any type of info would be appreciated.