EGR Cleaning Question

[andy]

Hi all,

I'm trying to address the P0401 code my 96 SC has been throwing for some time now. I went through the process of cleaning the EGR system as described in this great blog post using zenseeker's photos--->


http://reactionprevia.blogspot.com/2...ode-p0401.html


My inlet tubes and were pretty blocked up with crud and I cleaned them out. My question is regarding the exhaust tube routing up and over to the EGR valve. Should I unbolt this and clean out the metal tube? I have a spare gasket for this connection but haven't seen any specific direction with this piece....My van has always had a high idle and I'm wondering if the EGR code has something to do with it....maybe it's a vacuum leak somewhere or the EGR valve itself is malfunctioning? I’m just trying to check things off the list.

Thanks!
05-egr_exhaust_tube.jpg

[John Kaufmann]

It has been years since I did that job and my memory is not the greatest, but I recall deciding that I could not pull that tube without dropping the engine, which I did not want to do for just that. I ended up running a cable back through the tube from the valve end to convince myself it was not blocked. That must have been the case because the code cleared after the rest of the cleaning -- of which the worst parts were the coolest areas (on the intake side). If you find a way to remove that tube without dropping the engine, please post.

[eastman51]

I see that you have an SC van, so I would take a guess that your high idle is actually likely to be the black flakes in the coolant T-junction by the IAC and air intake hose underneath the front hood.
All the EGR does is redirect exhaust gases into the intake manifold, which allows the engine to run partly on unburnt fumes in the exhaust; thus the fuel trims can back off and you consume less fuel overall. It also improves emissions for the same reasons.

[Jonny]

Whenever the EGR system has a problem it must be verified that the vacuum modulator / solenoid is functioning. It is this component which is the brain for the EGR valve itself, and it commonly fails eventually. Take it out and see if there are "coffee grounds" under the fiber filter in the top, and whether you can blow any air through the large orifice on the bottom. If the answer is yes to either your modulator/solenoid is shagged. Search vacuum modulator on here and you will get more info.