Fuel Fuel pressure Issues / AFR


New Member
Mar 20, 2008
Dealing with a fuel pressure issue on my 89 fox. Recently installed a procharger p600b kit and trying to get it remote tuned. Tuner wants me to set fuel pressure to 39-40 psi. I have an aeromotive fpr and have backed the adjuster all the way out & can't get pressure below 43-45 with vacuum line off. When I put vacuum line on pressure stays the same. I am running a 255lph walboro pump with LU47lb injectors.

I have noticed if I plip the throttle fuel pressure drops. Should this happen? Also noticed my wideband is reading lean (+18)at idle, with my current setup and base tune if fuel pressure is at 43psi at idle.. If raise the fuel pressure to 65-70psi AFR goes to 17.5-16.5 at idle. However the car has to be pig rich like that because plugs are black and car reaks of fuel. Any help..thanks
  • Sponsors(?)