1998 Buick Regal 98buick Regal no injector Pulse

Did you use a gage to check fuel pressure, with the engine cranking? Even without an rpm signal, there would be an initial prime, when you cycle the key.

Once the vehicle is cranking, if the computer doesn't see an rpm signal, it won't pulse the injectors and it won't energize the pump relay. My info didn't show an oil pressure switch in the pump circuit, so that doesn't apply here.

It is possible for the proper cam and crank signals to be present and the computer doesn't it.