850 t5 fuel rail pressure

850 t5 fuel rail pressure 

when the feul rail is pressureized should it releve pressure down the return pipe ?before engine is started/ as mine isnt doing until the engine is started then it dose? ive tryed another filter,and 2 pumps plus changed rail pressure unit as i had probs last time with

Hi Powernut, The fuel pressure regulator is controlled by engine vacuum so it only allows fuel to flow back to the tank once engine vacuum is present. You should have full pump pressure with ignition and then the pressure will drop when the engine is started. Hope this helps, Paul.

cheers ,i just thought when the pump primed the fuel rail once up to pressure it releved some fuel in the return pipe ,,ill go check the rail pressures reason been have fault code fly up while driveing 231 ,and boost is rasieing slowley soon as i reset the ecu its off like a rocket for a while