been a while, but the pilot controlled valve shouldn't matter, the two pump check valves and the one after the FCU should be enough.
You have checked out the inline check valve after the fcu and before the nozzle right?
Also, as a final check, make sure all connections of flex tubes in the fuel cell are tight and that none of the pressure lines have chafed or have any small leaks.
Last edited by MLHeliwrench; 27th March 2011 at 18:39.