EGR and By-pass Valve - PeachParts Mercedes-Benz Forum

billhard · #1 02-02-2010, 10:22 PM

I am sorting out Vac issues on my 1985 CA version 300D. I attached a pic of the vac diagram on the car. What I want to know is item 14.20 labeled Electric vacuum control valve appears to do nothing but run the egr. If one want to disable this nasty thing for "testing" would simply not supplying this valve any vacuum be a satisfactory way?

Also what is 5.8 listed as By-pass Valve? This appears to be on the turbo housing.

Thanks for the help

dadette123 · #2 02-02-2010, 10:30 PM

Pic did not attach

billhard · #3 02-02-2010, 10:33 PM

OOPS ok i fixed it.

jt20 · #4 02-02-2010, 10:35 PM

yes, you can remove it.

make sure not to interrupt any signals to the trans or leave any new openings for vacuum to be lost.

DeliveryValve · #5 02-02-2010, 10:47 PM

This thread has some good information and diagrams (post #8 and #28) to help you out.

http://www.peachparts.com/shopforum/showthread.php?t=264272

.

LUVMBDiesels · #6 02-03-2010, 06:50 AM

I yanked mine and removed all the vacuum lines that cross in front of the engine. The car runs MUCH better!

I removed the four way "Tee" and replaced it with a "Y" if i remember correctly. No vacuum leaks

Oh and if you take the EGR off the manifold, you will see that a quarter (.25) will fill the hole perfectly! I put in my quarter and then bolted the EGR back on the manifold.

billhard · #7 02-03-2010, 09:31 AM

Thanks everyone, but what is item 5.8 listed as By-pass Valve? This appears to be on the turbo housing.

LUVMBDiesels · #8 02-03-2010, 09:52 AM

That valve releases boost into the atmosphere keeping boost pressure low in the intake when the engine is cold if I recall correctly. It was promptly disconnected on my SDL...

It is not the same as the wastegate.