Mini Copper s R56 2012

When the fuel Gage shows 1/4 tank, I run out of gas. the issue to the fuel levels not being equalized between the passenger side (fuel filter side) lobe and the driver side (fuel pump side) lobe. I have fully removed the fuel pump and fuel filter housing, checked and verified that both fuel level sending units are within specification . Excess fuel from the fuel filter housing is supposed to return to the fuel pump and suction transfer fuel from the passenger side lobe to the driver side lobe to keep both sides at the same level. I have verified this is not working as the driver side lobe is completely empty while the passenger side lobe still has a few inches of fuel.
is my lack of fuel transfer an issue of the solenoid or a valve>>>> ? do I need a whole new fuel system assembly?

 

This is the 3rd gen (F54, F55, F56, F57) area. Your R56 is a 2nd gen car, so you will have more luck with an answer in that area of the site.