Several general thoughts here, although I am not familiar with the 144E. Do you have an electrical schematic or Volvo shop manual? Original Volvo shop manuals for 240 series were very detailed. If the 144E has the Bosch Mechanical fuel injection system, the early 240 shop manuals may be instructive....

“… now the fuel system will not pressure up for the normal 1-2 seconds when turning on ignition…”

Does the pump run once you start cranking the starter?

“….Fuel pump still works…”

Does it only run when you connect power directly to the pump?

Please make a photo of that you have under the hood. I belive it should be D-jetronic(I only once worked on this car and it was close to 20 years ago). However diferent cars can be equipped with K-jetronic or KE-Jetronic system. When the last time this car was running? Was it running fine? What was ...

Vova585: Yes, a ‘73 144E would be a D-Jet.

Macdnife: If you run power directly to the pump will the engine start?
Have you tried removing the fuses and cleaning their tips and contacts on the fuse block?