i having problems starting/running my rotor. i suspect it may be due to low fuel pressure.

what sort of fuel pressure should i have when i have the ign on (fuel pump turns on, but engine not running)? i get around 40psi, then when the fuel pump cuts out it drops relatively fast until it reaches roughly 20psi where it continues to drop slowly. does this seem right? what sort of fuel pressure should i have while cranking?

this is on a s5 13bt, with some 600hp internal bosch fuel pump, malpassi fuel pressure regulator, stndard FPR removed.

cheers
Felix

 

40 psi is normal but i think it should hold the pressure longer than that.