Greg, The accumulator maintains pressure in the fuel system after the engine is switched off and has a smoothing effect on the gas flow while the engine is running. The primary pressure regulator in the fuel system maintains the pressure on the system while the fuel pump is running. The fuel pump delivers more gas than the system needs to run with and the primary pressure regulator will allow it to bleed back to the tank after about 5bar. I would look there for the pressure. John Hervey http://www.specialtauto.com/