i think my egr valve is malfunctioning b/c when i put the vacuum pump on the egr valve w/the engine idling the engine does not react at all. so does this mean it is bad? if so can i do w/o the egr valve?

 

If it does not open when you put vacuum to it, basically you are "doing without" the EGR, now (as long as it is not stuck partially open). You can do without it, but it does have some benefits as far as lowering combustion temperatures and controlling detonation.

EGR info

 

Ok, since this came up... I had the EGR tube break *between the manifold and the intake* So I blocked it off. Do I need to remove the valve? or do you recommend replacing that tube? I frequently ran the car hard... and I dont know if it will effect anything. Also will a different cam change this decision?

 

Just because you put vacuum to the EGR valve with the engine running and it doesn't open does not mean the valve is bad. Our car have an EGR valve with a "vacuum transduser" (sp) in it. When I was trying to sort out all of my EGR problems I took my brand new EGR valve in my hand and applied vacuum to it. It opened normally. I then put it on my car, let the car idle, and applied vacuum again. The valve DID NOT open. Boy did that blow my mind, until I took it off again and had a close look at it. In the end of the valve exposed to the exhaust gases when the valve is closed, I found a small valve that when opened "bleeds off" all the vacuum on the diaphram, causing the valve to close. This is exactly why our cars have EGR problems with free flowing exhaust. Our cars need no or some back pressure for the EGR to function properly, but when we add headers and maybe even a cat back it is possible with the better scavenging of the exhaust that the EGR valve will see a slight, and it doesn't take much, vacuum on the exhaust side. The valve will NEVER open, even though there is nothing wrong with the system. I modified my valve (welded up the end where the second valve is) so that no matter what, when vacuum is applied to the valve it will open. I still had EGR problems because the ecm did not see enough rise in MAP when the valve opened.

 

Just an update for those that are throwing the ses code 400
EGR (MALFUNCTION). i had mine removed and the code deleted, car runs great, no stumbling or pausing between 1200 -
2000 rpms.
zoso