I just finished installing my Racetronix fuel pump and wiring harness. With the key on and engine off, the pump will prime to 50 psi then settle at 38 psi when the pump stops. At idle, the fuel pressure will stay steady at approximately 41 psi. With the vacuum line disconnected from the regulator, pressure jumps to approximately 49 psi. This is normal ain't it? I read that with the KOEO, the pressure should be 41-47 psi. Is there something wrong?

 

The GM specs for fuel pressure are 41-47psi at idle with the vacuum compensation line off. The "best" pressure would be 43.5psi, since that is the pressure the GM LT1 injectors are rated at. Reconnecting the vacuum line will drop the rail pressure proportional to intake manifold vacuum, so a drop of 6-8psi from the "no vacuum" reading would be expected for a stock cam. Less drop for a more aggressive cam.

The slghtly higher pressure (49psi) will result in the injectors flowing about 6% more fuel than they would at 43.5psi. The long term fuel corrections should be able to compensate for that error.

Appears you do not have any significant mods at this time?