hmmm, first paragraph here says you should prime the system via feeding pressurized oil in through the oil pressure sensor port. Engine Lubrication

 

I like the other way " Lube the new seals on the new pump, dump oil in the pump to prime it (it will not prime itself)", I guess you just fill it up and then dump it out and put it on the engine?

Also, the pump that was on the car had plenty of oil inside the pump, so I don't think that was the issue either.

 

Seems like overkill. Some say to pack the oil pump with grease or vaseline to ensure that the pump primes on first start-up.