EGR - can someone explain operation please ?

I have been wondering about this for a while, so can someone please
enlighten me what this does, and what are the pros and cons of it, and risks
if disconnected, if any ?

I have a 2.5 TDi V70 (1997 - Direct Injection) and am always looking for
more economy ( or more power ) so if anything useful can be done to this
engine I would be especially interested.

Thanks,

Nick

 

It returns exhaust gas to the air intake when the engine is running at
a load slightly above idle. It is supposed to cool the combustion and
therefore lower NOX emissions. I'm also wondering about whether it is
useful, as i get about 15% more economy (and a bit more power) with it
disconnected at the moment. When it was disconnected when i got the
car, it would have been like that for at least 2 years, with no short
term damage, i cant say anything about long term damage though.

 

Hi Josh - thanks for the reply...

Does it open at high vacuum levels do you know, and therefore controlled by
a vacuum hose, or
is the control a bit more complicated than that ? If so I could try a short
term test by removing a vacuum hose.

Thanks,

Nick

 

In my old 240 it is controlled by vacuum, turns on when the engine is
at low load, switches off at about half to full load. In other cars it
is computer controlled, to be honest, i have no idea about yours. Try
looking for a diaphram near the rear of the engine block, if it is
vacuum controlled it will have one of these that will lead you to the
exhaust. If you have a hand vacuum pump, connect it to the diaphram
and apply vacuum, if the engine battles its probably the EGR control.
If it doesnt, its probably computer controlled

 

OK - thanks for the info - I will take a look

Cheers,

Nick