Just got this 3 cyl diesel back together and installed. Stop engine lamp flashing while running. Checked the oil pressure at the oil pressure switch port beside the turbo supply and found about 3 psi. Throttled the engine up and the pressure came up to around 6 psi. This is a complete rebuild and I can't understand this. I pulled the 1/8" plug from the casting there at the oil pump drive and I have 55 psi oil pressure. I am wondering if the machine shop may have removed a plug at the front of the block that I missed or could it be something else. I did remove and reinstall the piston cooler jets in the main bearing webbings. I am just missing something. Has anyone got an idea where this oil galley leads?