New fuel pump doesn't build enough pressure

What is your question?

I have a family van that sat for about 10 years, I began troubleshooting to get it running, so far it has ne ignition coils, spark plugs, starter, fuel tank and pump. I can get it to start for a second on starting fluid. When I checked the fuel pressure at the fuel rail it only builds 10psi when it primes, if you reprime it it will build up to 40, but if you purge it, it does not rebuild. I disconnected the fuel line before the fuel filter and turned the key and it just gave me a squirt. I'm at a complete loss and nothing on the internet seems to describe this.

What makes this problem better or worse?

Nothing

How long has your 2002 Ford E-250 Econoline had this problem?

A few weeks