egr valve

[kmaysob]

i dont get this. if its better to block off the egr, then why would you even bother cleaning the soot that is blocking it? wouldnt it work just the same?

[rwthomas1]

If the soot is blocking the EGR then it is also likely blocking some of the intake passages as well. Cleaning it out and then making a block-off plate cures the problem permanently. RT

[kmaysob]

on mine the only thing that looked blocked was the hole where the egr mounts was the only thing that looked really sooted. but then again i probably should pull the manifold and soak it in my parts washer full of diesel. i just need to get the gasket. does it perform any better with the egr functioning

[wolf_walker]

Performance is generaly better with it NOT functioning. And it's the crud you can't see that is bad. It's a stupid thing to have on a diesel, VW is haveing trouble with it to this day.

Originally posted by kmaysob
does it perform any better with the egr functioning

All a diesel needs is clean oxygen to burn fuel. Anything else will help (oil vapor) or hurt (Carbon dioxide) combustion. The EGR lets already burnt exhaust gasses back in. This just lowers combustion temps to reduce NOx formation. Since exhaust is oxygen poor, it can only hurt performance.

[kmaysob]

then why dont they make it legle to take off

[wolf_walker]

Because, while it works, it lowers Nox in the exhaust, one of the few things diesel is high on the polution scale with. Thank you EPA..

Originally posted by wolf_walker
Because, while it works, it lowers Nox in the exhaust, one of the few things diesel is high on the polution scale with. Thank you EPA..

Exactly why the Cummins Signature series (600hp) of the pre '02 are such a rare and wonderful engine over the water-cooled EGR version (550hp).

http://www.cummins.com/na/pages/en/products/trucks/isx.cfm

"The ISX uses cooled exhaust gas recirculation (EGR) to reduce emissions, without sacrificing customers’ needs for performance, reliability, and fuel economy."