Vehicle will not start after sitting for ten years

I got this vehicle from this guy who parked it ten years ago just parked it. And just never touch it again prior to parking he had some work done to the vehicle like timing and all that saw a receipt for $800.00 worth of work. Anyways, I flushed the motor, drain the tank, put fresh gas in it and now the fuel pump is not activating. I bypassed the relay and get the fuel pump to work, but it continuously pushes the fuel through the system and back into the tank. It does not build pressure. So I was wondering what would be the cause for that? The only way that I have been able to get vehicle to start so far is to spray some starting fluid down the throttle body. The vehicle is like a barn find never never had a bunch of people tinkering around with it. It is all straight factory dude parked ten years ago walked away without touching it again. Ran perfectly fine when it was parked so it should have been just flush the motor and the tank put a battery in it and it should have fired right up. Unless, there are a couple of steps I am missing? If you could give me your input though I will greatly appreciate it because I am getting tired of walking around town really could use a car right now.