Fuel system question for 24V 6 cylinder W202 and W124
 

I see a Schrader valve near the top of the engine which is used to check fuel pressure with a gauge. I have a fuel system bypass tool kit that would introduce fuel into that valve under pressure allowing the car to start with a bad fuel pump. The question is, does the fuel pump have a one way check valve so that the fuel I put in there, wouldn't just all go back into the tank?

Yes each fuel pump has its own check valve.

Ok thanks.