How many fuel pumps?

[nujon]

In addition to the mechanical lift and HP injection pumps on the front of the engine, my (sometimes dubious) Haynes manual says my W203 c220 cdi also has an electric fuel pump in the tank integrated with the fuel guage sender - anyone know if this is actually the case?

 

[grober]

In addition to the mechanical lift and HP injection pumps on the front of the engine, my (sometimes dubious) Haynes manual says my W203 c220 cdi also has an electric fuel pump in the tank integrated with the fuel guage sender - anyone know if this is actually the case?

Lift the rear seat cushions pull back the sound deadening and undo the large access panel and you will see for yourself ? A according to Haynes there are 2 sender units one with an inbuilt pump. In this pic the delivery unit=sender plus pump is item 50 and the sender alone is item 100. there may be minor differences in your model?

 

[nujon]

Thanks Grober

Daft question i know - but if there is a 'lift-pump' at the engine, what does the 'auxiliary pump' in the tank do?

 

[BlackC55]

Some have a pump in the tank and some don't. The early cars don't.

Best way to tell is to look at the fuel filter. Are the pipes on the fuel filter at a right angle?

 

[grober]

Sorry if I confused things- my diagram is from a later model car.

 

[nujon]

Thanks anyway grober - on investigation, whilst my car has both a fuel pump fuse and relay fitted in the rear SAM (which audibly clicks when the ignition is switched on) , the fuel tank connector has only the two pins for the fuel guage sender unit - so no pump fitted! (might have been one originally though?)

I wonder if pumps were later fitted to overcome airlocking following maintenance of the fuel supply system (e.g. fuel filter change?)

Regards