On Wednesday, April 26, 2006 at 3:43:19 AM UTC-10, Nehmo wrote:
> I successfully changed the fuel pump on my 2001 Ford Ranger 3.0L 126"
> wheelbase, flex-fuel truck [1]. But I have some unanswered questions,
> and they'll plague me the rest of my life if they remain so.
>
> Is there a fuel pump timer? How does it work, and where is it?
>
> If indeed, the pump is cooled by fuel going *through* the pump, what's
> the advantage of placing the pump *in* the tank?
>
> How come Ford has different pumps for different wheelbase trucks that
> are the same otherwise? How can the wheelbase, differing by a few
> inches, have anything to do with the pump?
>
> [1] The "flex-fuel", meaning can take either methanol+gasoline mix or
> straight gas, part is indicated by the 8th character of the VIN, V for
> flex-fuel, U for only straight gas. Apparently that detail is needed to
> get the correct pump.
> --
> (||) Nehmo (||)

It's simple enough to find out if the fuel pump is running with the engine off - you just listen for it. You can stick your ear against the body to hear this.

The fuel pump is probably located in the fuel tank so that it still operates even when there's vapor in the lines. It's probably faster and cheaper to install.

The main reason for different pumps is to supply different flow rates. The bigger the engine, the bigger a pump it will require.