Fuel pressure regulator- hard start

[Caribbean ZJ]

Just changed this part 2 days ago due to gas leakage. Followed all instuctions and relieved fuel pressure by removing the gas cap & pressing valve on the fuel rail. After install,turning the key took about 3 seconds longer to crank. i expected this since fuel pressure had to be built up in the rail. However 2 days after it still starts like this wether hot or cold. The jeep never behaved like this before changing the part. Is this behaviour normal & would get better with time?
Is there someway of rebuilding gas pressure after install that i didnt do?
What does this part do anyway?
i did noticed a little bit of smoother idle & better gas milage

[glennco1]

The fuel pressure regulator routes gasoline back into the tank if the pressure goes above a certain amount. (this changes based on engine configuration)

When you turn the key to the on position the fuel pump should turn on momentarily until the fuel pressure builds. After this time, you should never see the issue again. If you see it every time you start, you are bleeding pressure back into the tank.

[Caribbean ZJ]

Break it down some more Glenn, how do i stop bleeding pressure back into the tank. Is the part not doing its job. The original looks silver but the replacement is black, Straight from dealer. Think i got the wrong part?