OEM fuel pump questions

[Scullies]

1 - How does the OEM fuel pump know when the system is pressurized?

I assume there is some kind of sensor in the pump or the priming process is only based on a certain amount of time the pump stays on before it stops the priming process.
If there is some kind of sensor, then question 2 applies

2 - With a surge tank fitted, how does this sensor register a pressure? As the fuel is being pumped into the surge tank, which has an outlet that allows the fuel to flow directly back to the tank.

 

[<tuffty/>]

The fuel system has a fuel return, the pump will always be flat out but by design will draw more current as load increases to keep up with the extra pressure as boost is applied to the FPR..

On initial priming the pump is just run for a set amount of time... won't make any difference that you have an inline pump or surge tank in the way... it will pump the same but won't draw as much current to do it...

<tuffty/>

 

[Scullies]

Awesome, and as always thanks for sharing your knowledge