What is the difference between the two? I have a fabia 1.9tdi comfort est & are looking to change????

The 1.9 is a PD engine.

Longer: The 'old' style PD Pumpe Duse engines use one pump and injector unit per cylinder. The new CR common rail engines have one pump for all cylinders and different injectors.

http://en.wikipedia.org/wiki/Unit_Injector

That may confuse you LOL

http://www.tracking4u.co.uk/styled-2/styled-16/

That may be a little easier to understand.

"Pompe Duse" (PD) is VAG's own brand name for a unit injector engine, which combines a separate hp fuel pump for each cylinder with the injector. It's not really an upgrade; just different technology.

Pumpe Duse is a fuel management and delivery system that places a pump injector at each individual cylinder producing a finer spray for better and more efficient combustion. Instead of a pre-combustion chamber found in most diesels, fuel is injected directly into each individual combustion chamber under terrific pressure at precisely the right moment.

The PD works like an overhead cam system, using cam lobes to determine the timing and amount of the spray into each cylinder. The new system reduces heat loss, results in a quieter, cleaner engine, faster cold weather starts and improved low-end torque

A diesel engine with the PD pump injection system has the following advantages over an engine with a distributor injection pump such as found on the original 1.9L TDI engine.

Depending on you budget common rail diesel is the newest tech...

However, there's much more to come: two engines that look to maximise the benefits of both diesel and petrol engines are currently under development.

VW's new petrol engines will use highly accurate fuel injection and a new type of combustion process, known as GCI (gasoline compression ignition). With GCI, exhaust gases are mixed with petrol to create an explosive charge without the need for a spark plug. The results are greater fuel economy and a significant decrease in emissions.

Similar experimental technology is being brought to bear on a diesel-based engine known as the CCS (combined combustion system), which, along with even greater fuel efficiency, will be able to run on the new biofuels.

Edited 5 February, 201313 yr by corfyboy

The PD system has a little pump for each injector, the pump is pressurised by a cam, and at the right moment piezo controlled valves allow fuel into the cylinder.

The main issue as far as I know is that the cam can wear down due to the forces involved, but as long as you use the right oil you should be fine.

Common rail means you have one pump pressurizing the "rail" which is "common" to each injector, the injectors jut pulse open and shut to allow fuel to enter. Pressures are higher and the electronics allow precise control, and sometimes several squirts of fuel a few milliseconds apart to give less knock.

Main issues here are the cost of the injectors if they go wrong.