I have a 1990 300E which failed emission for high NOx. I found out that the vaccum pipes going from the EGR valve to the front right fender are broken. There are two solenoids with more pipes. I dont know where the EGR vaccum pipe should be attached to which solenoids. There is vaccum in one pipe which has been blocked by the ex-owner. Is some one can help me either with a diagram or otherwise, I will appreciate it.
Thanks

 

I figured it out. Should there be continuous vaccum at the EGR valve or is it controlled by the computer? At idle, I pulled the vaccum tube attached to the EGR but there is no vaccum although it is present at the solenoid located on inner sidepassenger side fender behind the windshield washer tank. At the solenoid, top feed is vaccum line and side feed goes to the EGR valve. Thanks.