As the post says is it electrically driven by the engine management system or is it driven off the back of the engine and has electrical input from the engine management system?

Advice please

What do you mean by Tandem Pump? The vacuum pump?

Or the hydraulic pump with electric motor?

It's belt driven. Not sure if/how it is controlled.

Its combined with the vacuum pump and driven off the end of the camshaft.

Its not controlled other than a pressure limiting valve.

i mean the 2nd pump that suppies the injectors. How is pressure controlled to the injectors as i assume they just pressurise the diesel so i assume its done on flow not pressure. sorry for the confusion

PD engines use a pump/injector which is a pressure-generating pump combined with a solenoid valve control unit and an injector. Each cylinder has its own pump/injector which means that there is no need for a high-pressure line or a distributor injector pump.

As with a conventional system using a distributor injection pump and separate injectors, the pump injection (PD) system must generate the high injection pressures required and inject fuel into the cylinders in the correct quantity and at the correct point in time.

Does that answer your question?

For more info on the PD sytem try this -

http://www.fabia-vrs.com/downloads/files/injection.pdf

PD engines use a pump/injector which is a pressure-generating pump combined with a solenoid valve control unit and an injector. Each cylinder has its own pump/injector which means that there is no need for a high-pressure line or a distributor injector pump.

As with a conventional system using a distributor injection pump and separate injectors' date=' the pump injection (PD) system must generate the high injection pressures required and inject fuel into the cylinders in the correct quantity and at the correct point in time.

Does that answer your question?[/quote']

pulled straight from the PD engine Spec PDF!

pulled straight from the PD engine Spec PDF!

I have the document but not the link - and a very interesting read it is too. .

The tandem pump is still driven off the engine as i said..lol

There are six pumps in the system in total.

1 x Lift pump in the tank

1 x Tandem pump on the engine

4 x Unit injectors.

I could quote the pressures if you like?