Lift pump

[Misternw87]

As has been pointed out several times, unless your 2001 TDI ALH engined vehicle has been altered it never came equipped with a "pump" in the tank ever and you are not only incorrect in your assumptions but also posting in the wrong forum area.

No your wrong Colonel Sanders

 

[pedroYUL]

No I know the difference what I was asking about has never changed. I never once asked about a fuel pump OR sending unit which I did state the difference in my original post a little reading goes a long ways like you It’s always been about a lift pump. Someone else made it about a fuel pump. Aka sending unit

We call fuel pumps any or all of these (different flavors): tandem pump, injection pump (VE type), high pressure fuel pump HPFP. A sending unit doesn't pump anything

 

[Misternw87]

We call fuel pumps any or all of these (different flavors): tandem pump, injection pump (VE type), high pressure fuel pump HPFP. A sending unit doesn't pump anything

WHAT ARE YOU EVEN TALKING ABOUT. Your kidding right. All of those things you named off are different. The sending unit absolutely pumps fuel and sends it too the injection pump where it it converts 100psi to 19,000psi per injector. For every quarter turn on the pump collar (could be wrong on that one, it maybe called something else look up a diagram of you Injection pump if want specifics) however the cam inside the IP will have done 4 rotations sending fuel through the injectors and any excess fuel is returned to the filter to be filtered out and reused.