I wonder if it is a pressure regulator, which will keep the pressure at the injectors around 55psi - 60psi, and it has jammed closed? The solution may be to do away with it, or at least take the innards out and buy an after market regulator which can be set at whatever pressure is desired.
All fuel injection cars need a regulator as the high pressure fuel pump sends the fuel around the system at over 100psi which could damage the engine and will overfuel it.
If you go down the aftermarket route, don't get one of those cheap £30 ones, they tend to fail, pay at least £50 - £75.
