I have recently replaced all rubber fuel lines on my 1978 450SL (cis) fuel delivery system. I also replaced the fuel filter. I put approximately 5 gallons of gas in the gas tank. When I turn on the ignition switch there is no voltage to the fuel pump. When I attempt to start the car I get 10 volts across the fuel pump but the car does start. After I release the ignition switch I can hear the fuel pump still running for a few seconds. Am I missing something obvious here.