fuel pump help

[t930928]

Bringing 77 930 back to life. Not run since 89. I cleaned fuel tank, cleaned screen. Car started and idled great but lots of noise from pumps and would blow fuse. Would not rev over 3k. Replaced both pumps. Have trouble bleeding system. Fuel lines will only sing intermittently. Both pumps audibly operating. After bleeding Car will start and run for a few seonds then dies. removed fuel line from filter to fuel distributer to check output of pumps. It pumps great for a few seconds then dies to nothing. Put a hand vacum pump on line and it pulls gas easily. disconnected forward pump discharge and get good flow. disconnected after pump discharge and get good flow. disconnect at fuel distributer and get good flow for ten seconds then it dies to nothing. What am I missing?

[David]

How did you clean the tank? After sitting that many years I would expect a lot of rust.

[t930928]

The tank had been left with fuel in it to minimize rust. I removed the tank, Cleaned with degreaser twice. Hot soap and water twice. With the tank out I could really slosh the liquid around in the tank. A good ten minutes of vgorous sloshing each time. After a good dry with forced air from vac I sloshed oshporic acid around the inside to convert any small rust spots into ferrous nitrite. then washed one more time and gave a good dry. Looking through sender unit opening the tank looked brand new inside.
Further trouble shooting today makes me think the rebuilt forward pump is the problem. It was making Alot of noise and when i totally disconnected the output line it did not have much output. After removing the pump I took a suck on the tank with a hand powered vacumn pump to check for rust and found fuel was clean and clear.

[David]

These are usually relatively quiet pumps so that may be the problem. Have you checked the amps on the pump?