Still no joy. I have replaced just about everything I can think of.
New fuel pump,
New fuel filter,
New accumulator,
New pressure regulator.

When I fired everything up, still no start. I have 0.4 bar of differential pressure and was holding 4.9 to 5.3 bar of pressure. Shut the FP off and checked the accumulator for leaks. Found some fuel and I was able to tighten one more flat of the nut and the leak was fixed.

When I started the FP again the pressure would only reach 4 bar and no differential pressure.

Is my new FP defective?