MBZ5.0

Hi everyone, I have a 5.0 in my 1984 190E with the original Mercedes fuel pump. I want to use a Ford pump but they are all in-tank applications (unlike the mercedes unit) and I'd rather not have to fab one into the Mercedes tank if I can help it. Is there any way to modify an in-tank Ford fuel pump to run externally? The ecu shows a failure in the fuel pump diagnostic because it needs the Ford pump to communicate with so I'm hoping someone here can help me out on how to proceed. BTW I can hear the ecu turning on the fuel pump but the result is the car won't start when cold without starting fluid, once it's been run it can be turned off and restarted just fine. The next morning though, it'll take a shot of starting fluid to fire up. Thanks for the help!