Bryans12v

I did the EGR passage cleaning about 3 months ago. During the process I made a booboo. On the upper portion of the manifold, theres a linkage on the back that connects to the vacuum unit for the manifold. I sort of bent it. Grabbed a pair of needle nose pliers and tried to straighten it and in the process pulled the whole linkage off of the unit.

I managed to somehow re-attatch the linkage to the manifold but now everytime I come to a stop a few seconds later the rpms will drop all the way down and kick back up again, sometimes even stall. I believe the problem to be related to that linkage and the vacuum not holding or releasing when the car will kick down to idle. I know the linkage is still somewhat nat as straight as it should be or not following the same line of travel it should.

I sourced another complete manifold for a 100 bucks out of a boneyard which is a pretty damn good deal. Which brings me to my next question..

The vacuum unit that the linkage connects to, does the position of the vacuum unit make a difference when I reconnect it or will it move into its proper position when the car is started?

I think this diaphram valve is an open or closed only valve, am I wrong? If so, does its open or closed position make a difference when the car isnt running, like will it default as soon as it goes into vacuum?

Its been one thing after the other with this car lately, though, I still love her dearly.

wolfman_dc

The changeover valves inside the manifold are open-close only. There is no throttling. The vacuum servo should only fit on the manifold one way. The linkage will adjust itself to the proper position.

Mr.D-'97 A4q 12v

the correct position.

Be very careful removing the "servo" from the junkyard manifold. The plastic for the ball end becomes very brittle with age and breaks easily. I broke mine trying to remove it and had to buy a new one.

One other note, if you find it necessary to replace the top part of the manifold you can't while it is on the car. There are four long bolts through the bottom of the manifold which screw into the top. The whole manifold needs to come out.

Your problem may be your ICV.

audijim113

was looking at them (actually feeling them) when i cleaned the egr port out. i wondered what they do? what ports do they open or close and when?

moribundman

... for optimizing torque at low and high RPM via a shorter and a longer intake runner path.