Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-17-2017, 10:27 PM
Registered User
 
Join Date: Apr 2017
Posts: 5
EGR pressure converter valve function - 1984 300D

Hello all, the EGR pressure converter valve on my 1984 300 Turbo seems to run (make noise) for about two minutes after I shut the car off. This is the valve hanging on the right front inner fender under the hood behind the headlight.

I've been searching quite a bit and can't seem to figure out why! Any insight would be greatly appreciated.

Click image for larger version

Name:	IMG_2635.JPG
Views:	212
Size:	327.0 KB
ID:	142280

Reply With Quote
  #2  
Old 05-17-2017, 11:34 PM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Posts: 6,025
It has a vacuum diaphragm in it that's likely leaking. What you're hearing is probably the vacuum bleeding down.

Block off the vacuum line coming to it from the vacuum pump with a BB or ball bearing and don't lose any sleep over it.
Reply With Quote
  #3  
Old 05-18-2017, 08:21 AM
Registered User
 
Join Date: Dec 2006
Posts: 3,941
That's exactly correct (except the part about blocking the line). The valves often don't completely seal at shutdown, and they allow the vacuum to gradually bleed down. I'm not sure why this is, but I've gone through several used transducers and they all have the same behavior. Despite this apparent leak, they do work correctly when everything is energized.
Reply With Quote
  #4  
Old 05-18-2017, 07:58 PM
Registered User
 
Join Date: Apr 2017
Posts: 5
You are both correct, I verified and it's definitely vacuum leaking down. As long as it doesn't represent a leak during operation, I suppose I'll just disregard! Or perhaps an excuse to disable the EGR in its entirety.

P.S. Thanks for the quick responses, I guess peachparts will be my new go-to. My benzworld post fell on deaf ears!
Reply With Quote
  #5  
Old 05-18-2017, 09:37 PM
Registered User
 
Join Date: Dec 2006
Posts: 3,941
Quote:
Originally Posted by dmarti02 View Post
Or perhaps an excuse to disable the EGR in its entirety.
There's really no reason to do that. I should have added that the way to test the function of the transducer (and the entire EGR control system) is to add a "T" to the EGR vacuum line. Run a temporary vacuum gauge off the T and bring it into the cabin through the passenger window. Whey you drive, EGR should be near zero at idle or at full throttle. The only place you will have peak EGR vacuum is at steady cruise. This tells you that the EGR system has minimal impact on performance. It's turned off as soon as you get on the pedal.

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 03:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page