Wha is this?

Hiya guy's, sorry for probably asking a stupid question but only recently started to look into the mechanical side of things on car's. Just been looking around on the 300TDI (Dorothy) and was wondering what this is...

Thanks in advance

Alex.

lift pump

Cheers for the reply.

Any chance of explaining what it does? Sorry for being such a dimwit ha. :laugh:

Lifts fuel

It's a fuel lift pump. It pulls fuel from the tank into the engine bay then to the fuel filter. The fuel injection pump is capable of pumping fuel from the tank on its own but it will lower performance and increase the amount of work it has to do. Thus the lift pump does the heavy work, then the injection pump can do the 'precise' bit

I read in one of the monthly mags that you can test if the lift pump is failing by:-
' undo doing the bleed screw on the fuel filter. If no fuel drains then the lift pump is failing as fuel is just been sucked through'
Is this correct ?

no ,you can test pump works by pumping it and fuel flows but a poor seating valve that lets fuel run backwards overnight isnt so easy to see