Fuel Pressure????

[gards]

I have a 1988 2.3 L 190E that is having a hard start after it is warmed up. We put the fuel pressure gauge on the distributor and found that the pressure was 5.2 Bar. I was told that it needed to be about 6.2 bar.

Does anyone know if that is true? If it is true what would be the part that controls that. I have already replaced the FP regulator and that did not increase the fuel pressure. I have also done a fuel pump volume test and it pumps plenty.

If any one has any ideas that would be great. I have been trying to solve this problem for six months and I have replaced almost everything except the wires, cap, and rotor.

Thanks,

Gards