Cadillac Repair: fuel pumps, fuel pressure regulator, wireing diagram

Question
I replaced both fuel pumps on my 1979 caddy but the new pumps do not seem to work I even replace the fuel filters. It doen not pump fuel from the gas tank. I replaced the pump on the frame on the pump in the tank. What am I doing wrong?

Answer
Hi Russell, I don't have access to a '79 seville wireing diagram. However the system should have a fuse and relay that needs to be checked. Then there is a fuel pressue tap on the rail that a gauge gets screwed onto to test fuel pressure. Sometimes on the older cars the fuel pressure regulator diaphram leaks allowing gas to go through the vacuum hose into the engine and will cause starting problems. The frame rail pump should be easy to test for power and ground. Maybe you have a broken wire or bad relay. The computors were also known for going bad and a special tester substituted for the ECU  turned on the pumps. You may have to have it towed to the shop but make sure they have the knowledge to work on it first. Sorry I can't be more help. Bill