My 90 GTU has been running like crap. Extremely rich and no power. I started looking for possible causes and saw that my Metering Oil Pump (MOP) lines where completely empty. When I tested the MOP it failed. The voltages at idle and when raising RPM failed by a long shot. All other checks of the pump passes i.e. the ECU and harness.

When I checked for codes all I got was 34 the BAC valve. I have the BAC valve blocked off so I know why that code is there. Does anyone know why this would happen? Why would my Electrical MOP stop pumping and ECU act like it is in limp mode without a code to back it up?

 

Any chance a previous owner swapped in an S4 ECU?

Good spot, catching the dry lines.
I assume you're premixing until you get it resolved.