E70 35D Stall while driving crank no start

[Phil C]

Originally Posted by Clavurion

Always during start and during running when coolant temp under 19 C flow control valve is fully closed (max flow to pump, no leak off from flow control valve) and pressure control is done by pressure regulator at the rear end of fuel rail.

https://www.pss-autosoft.net/diagram..._FBDDE6RDR.htm

Thanks for that. Do you happen to know if there is an internal bypass in the pump eg for cooling that will also be discharging into the return line? What I was hoping to do is to diagnose a non-closing flow control regulating valve by checking for discharge to the fuel return line while the valve is electrically disconnected.