Electromotive TEC3 tuning/repair

I have a custom setup. Rebello Big Bore, EFI, TEC3 ECU. Fuel delivery is from 1976 tank and 76 280Z electric fuel pump. The TEC3 normally activates the fuel pump with ignition on for 6-8 seconds to get fuel pressure to 40psi and enable starting. The fuel pump was new in 2022.

All has worked flawlessly until a few weeks ago, when the fuel pump stopped. Diagnosis is the TEC3 has quit sending power to it. Bypassing the wiring, the pump is perfectly fine. All relays and fuses check out good. At this point we are stuck.

Not sure exactly how the TEC3 was programmed to power the pump wiring. Maybe a GPO but things are on pause at the moment as I am away.

I realize the TEC3 is now ancient. I cannot find any support for it anywhere. The tuning app (WinTec3) runs on my equally ancient Dell Inspiron 8200 and Windows XP but is still operable.

I’m inclined to punt on the TEC3 and get a new ECU. But easier said than done. Wiring seems likely be a nightmare.

Ideas?