I'm finishing up the LT1 intake swap. I installed the fuel rails, injectors, new lines, and new AFPR last night. I removed the core from the schraeder valve and installed a permanent gauge. I turned the key on/off/on to pressure up and check for leaks and noticed only 25 psi on the gauge. I can't remember, but is it possible to adjust the FP with just the key on. I tried with no luck. I know I used to get full pressure when turning the key on before, but this setup has never had any vacuum on it. I'm still a few hours away from getting everything ready to fire this thing up, so I'll know if I have a problem then for sure.

 

The fuel pump only pulses on for a few seconds when the key is turned on. This is to prime the system. When you adjust fuel pressure you need a constant pressure supply from the pump or you will have an effect similar to trying to up the pressure on an air compessor tank with the power off and the tank at half the pressure that you are trying to achieve.