I spent all day yesterday at the dyno trying to figure out what the problem is. Maybe you guys can help me out. The problem is that my fuel pressure is not increasing with boost. I got the walbro 255 42# inj. aero. press reg. The pressure only goes up about 5 psi and it should increase 10 psi, cause that is how much boost im pushing. The press. reg. is a 1to 1 ratio. Do I have some vac. issues or what??????

 

sounds like a vac issue to me. see if you cant pressure test everything. that will let you know right away of any leaks.

another way would be to spray carb cleaner over the vac lines. any idle change will tell you there is a leak

 

Is the Aeromotive adjustable fuel pressure regulator boost sensitive?

Hooking up a hand held vacuum pump (available at Sears and most auto parts stores) will allow you to apply a controlled amount of vacuum to the regulator to verify the fuel pressure changes accordingly (check the fuel pressure with the car running and vac pump hooked up to the regulator). Likewise, you need to apply a small controlled amount of air pressure to the regulator as well and check for a fuel pressure increase (this could be done using a bicycle tire pump that also has a pressure gauge built into it).