fastest n/t...

[Tenshoa]

I just had my EGR valve replaced. You can block it off, but know this: 1) your CEL will stay on.. and 2) it doesnt make a noticable difference. So IMO its not worth it. Just change the valve. If you have someone else do it, it will run you about $250...and thats the lowest price I got around here. The dealer will get you for about $350. So if you can do it yourself, the valve will run you about $90.
Also to answer your question, when an EGR goes bad, it is generally stuck open, and held there by the carbon build-up. Sometimes you can take the valve off and clean it and that will do the trick for a little while.

 

[RACER-X]

thanks for the tip.

 

[Doug99RS]

Well that would tend to confirm that the EGR system may not be working properly. From what I've been told the EGR system was designed to cut down on NOx emissions. This is a biggy in large cities and Cali. Bear with me here cause what I'm about to say is nothing I can change and we're all just gonna have to nod our heads together and be upset together. But... I've been told that NOx itself is not bad. What it is though is a compound that makes the other pollutants in the atmosphere visible. So... you get rid of the component that makes the polution visible and then there's no more pollution right?? rrrrrriiiiiiggggghhhhttttt...... Kinda the osterich putting his head in the dirt and then all it's problems go away theory.

Anyways... on to something more substantial. The EGR system is designed to raise intake air temperatures by introducing exhaust gasses in to the intake air stream so that less gas has to be used (remember... 1 liter of cold air= 1Liter of air with a higher oxygen content, more oxygen means it throws more gas in, more gas and oxygen... the more you go). This helped to reduce NOx emissions. So... all that crud in your intake... well, it gets from your exhaust from your #4 cylinder exhaust port. It comes out of the cylinder, in to the port, in to the EGR valve, in to the tube that runs under your air snorkel and then to the back of the intake manifold. Well... this itty bitty tube from the valve to the intake is only about the size of one of those fatty pencils we used as kids (ok... I still use them but don't tell anyone). So as bad as it may seem inside your manifold... just think how bad it is inside this small, confined space in the tube. So... basically over time that tube and the egr valve get so full that it chokes off the exhaust flow. So now... you've rendered it inop and that's why you NOx has gone up.

As far as checking it... the only way you can really check the valve is by using a vacuum pump and applying vacuum to the diaphragm. The diaphragm should pull on that small metal pin you just barely can see. If it doesn't move... then the valve is stuck. In which position? Kinda hard to tell. But... just because the valve may move doesn't mean that the air way is clean. The valve could work fine just be clogged up before or after the valve.
Doug

 

[RACER-X]

so i should replace it then, right?

 

[na90dsm]

i would. thats probably your problem. i think im chaingin mine too with the build up i had in my intake mani.wasnt that bad but im gonna change it before it gets worse

 

[Bohica]

Originally posted by darkrage
how about fastest 1G n/a?

I'm working on that one.

 

[na90dsm]

im right behind you.