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 05-25-2015, 07:21 PM
Registered User
 
Join Date: May 2015
Posts: 3
Vacuum Nightmare

Hi.

I got a 1982 300sd with absolutely no vacuum lines.

I'm trying to figure out how to just get proper vacuum to the transmission, brake booster, and shutoff valve for the time being.

Forgive my ignorance as I have not worked on very many diesels. That's what fourms are for though, right? I'm here to learn.

Right now, I have a vacuum hose connected from the vacuum pump to the brake booster. In the middle of that hose, I have a T that I have connected to the VCV.

How and where do I hook up the line that goes to the transmission? Is there some sort of switchover valve that I have or should be using in this setup? As I understand, the connection on the bottom/side of the VCV is a vent. I don't understand how there's only one place for vacuum, and it's supposed to somehow be the input for vaccum AND the output for a seperate vacuum circuit to the transmission. What don't I understand?

Also - the shutoff valve. It works when I hook up my hand vac up to it, and shuts down the engine. However, my car will not start if it is hooked up. I have another T that goes to a connector on the firewall, that has a two wire plug, I assume for 12v voltage. The other vacuum hose on the connector goes to my shutoff valve.

I used my multimeter and I am getting only about 2 volts at those two wires when the key is on... should I be getting 12v?

Thanks, all.

Reply With Quote
  #2  
Old 05-25-2015, 08:27 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 51,180
Quote:
Originally Posted by Coatchawa View Post
Hi.

I got a 1982 300sd with absolutely no vacuum lines.

I'm trying to figure out how to just get proper vacuum to the transmission, brake booster, and shutoff valve for the time being.

Forgive my ignorance as I have not worked on very many diesels. That's what fourms are for though, right? I'm here to learn.

Right now, I have a vacuum hose connected from the vacuum pump to the brake booster. In the middle of that hose, I have a T that I have connected to the VCV.

How and where do I hook up the line that goes to the transmission? Is there some sort of switchover valve that I have or should be using in this setup? As I understand, the connection on the bottom/side of the VCV is a vent. I don't understand how there's only one place for vacuum, and it's supposed to somehow be the input for vaccum AND the output for a seperate vacuum circuit to the transmission. What don't I understand?

Also - the shutoff valve. It works when I hook up my hand vac up to it, and shuts down the engine. However, my car will not start if it is hooked up. I have another T that goes to a connector on the firewall, that has a two wire plug, I assume for 12v voltage. The other vacuum hose on the connector goes to my shutoff valve.

I used my multimeter and I am getting only about 2 volts at those two wires when the key is on... should I be getting 12v?

Thanks, all.
Someplace in the Repair Links there is links to sites with Vacuum Diagrams.
Fast navigation http://www.peachparts.com/shopforum/diy-links-parts-category/146034-fast-navigation-do-yourself-links.html
__________________
84 300D, 82 Volvo 244Gl Diesel
Reply With Quote
  #3  
Old 05-25-2015, 08:52 PM
Registered User
 
Join Date: Jul 2004
Location: Barrington, RI
Posts: 5,875
Or just do a Google search for your model and "vacuum diagram." All sorts of stuff comes up.
__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife
Reply With Quote
  #4  
Old 05-26-2015, 09:52 AM
tyl604's Avatar
Registered User
 
Join Date: Feb 2008
Location: Atlanta, GA
Posts: 3,641
Just so you know, your transmission will shift without vac. The upshifts will be perfect because the SD uses zero vac for upshift; however, the downshifts will clunk. SD uses vac for downshift only.
Reply With Quote
  #5  
Old 05-26-2015, 11:33 AM
Registered User
 
Join Date: Jun 2004
Location: West of Ft. Worth. TX
Posts: 4,186
Here are a few links that should help:

Mercedes-Benz 126 Service Manual Library
http://www.startekinfo.com/StarTek/outside/12253/program/Engine/617/14-050.pdf

The EGR diagram will have most of the engine area connections for vacuum (pg 7). Much of the EGR specific items can be bypassed "for testing".

More than likely, there is a line that directly connects the orifice (63) with the main orifice (62). Ensure that it is connected to the correct leg of the T-connection (62) and that orifice (63) is installed or there will be transmission shifting problems. Off the top of the VCV, you should have a 3-way connection to orifice (63) and the transmission. Off the bottom of the VCV, the connection (b) may go to the cabin vent line, eliminating the 3-way. The VCV causes a controlled variable vacuum between idle (high vac) and max acceleration (low vac).

Depending on your location, you may want to leave some of the EGR connections in order to pass inspections. Many do not have strict exhaust opacity tests but they do have regulations about removing emissions equipment. Since there is no testing, they do not know whether it is operational.

For the shut off valve, the connection should go inside the cabin to the ignition switch.

The switch on the firewall is for overboost protection. The lines for this should connect the the rear banjo-bolt on the rear of the intake manifold and to the alda compensator on the injection pump. Electrically, it connects to the boost pressure switch on the side of the intake manifold.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Last edited by SD Blue; 05-26-2015 at 11:57 AM.
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 03:00 AM.


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