I was wondering, in the stock Mercedes fuel setup, if one would block output port from filter, and also block return line from injectors and injection pump before it enters fuel filter, would fuel pumped by the stock lift pump find its way through banjo bolt into the return line to the tank?
MB w124 300TD, 1992, single tank Elsbett kit.
The banjo bolt on top of the filter housing has an orifice in it to bleed a very small portion of fuel back to the tank. A clever idea to keep air from getting to the injection pump, if a small leak develops in the suction side of the system. That is, between the tank and the pump.I had to block this hole on my SVO system. Maybe this will help.