Now I know exactly how the fuel pump works. But its still a pump that's it role a pump. You also forgot the regulators and what about the bellows as well. Now the pump dose not drive the fcu The fcu drives the pump in both cases lyc and TCM. Flows from both pumps will increase as the rpm rises. Now also fuel flow can be changed via the mixture lever as well as throttle position. The Fcu leads the pump follows.
...no.
On the Lyc (Bendix) system, the pump is merrily pumping away, potentially supplying more fuel than the engine needs. The FCU simply limits that output via a diaphragm which responds to pressure drop across a venturi, to arrive at the desired flow. The pump can go as hard as it likes, but the FCU controls flow. That's why the flow doesn't change when you switch on the boost pump and raise the input pressure.
Sorry, but you lost me ages ago when you claimed that TCM and Bendix systems work the same.
Next ive ask everyone I know and no one ive talk to has any idea how you are getting fuel flow pre pump and pre fcu this includes some extremely smart EIR guys I know.
You didn't ask me, and I'm not even that smart.
Boost pump -> inline sender -> EDP -> FCU. The sender measures the flow through the pipe, on its way to the engine.