No fuel pressure precharge?

[MTF]

What in the actual F, the fuel pump does run continuously. There are two returnless fuel system designs, and Ford has used both.

1: fuel pressure regulator removed from engine and placed inside the fuel tank so the excess fuel was dumped right back in the fuel tank instead of traveling all the way to the engine and then back picking up heat from the engine along the way. This was in the early days of returnless systems and has been abandoned for #2 in the past 15ish years.

2: fuel pump speed (which equals flow/output) is controlled by a fuel pump controller that is controlled by the PCM (ECM is the same thing). The fuel pump speed is based on fuel volume demand. A fuel rail pressure sensor is used as a feed back to the PCM so that fuel requirements can be maintained.

I assure you the pump runs all the time the engine is running, The pump in any fuel system will run as soon as the key is turned to the run position. If the engine is not started then the PCM will turn the pump off after 2 secs (20 sec on a ford diesel).

PS. There is actually a 3rd design but it is a modification of design #1, where the regulator is in the fuel filter and return fuel is sent back from the filter and never makes it to the hot engine, so semi-returnless really.

??? You just said what I said!
Or did you only read the first sentence?

 

[Canuck714]

You may also want to look at the Fuel Pump Driver Module.
Its located in a super handy (cough) location on top of the frame crossmember by Drivers Side Rear tire