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 07-04-2008, 10:35 AM
Registered User
 
Join Date: Dec 2003
Location: Festus MO
Posts: 762
What is this blue plastic pancake vacuum can?

I feel like I should know the answer to this, as I've been "into" these Benzes for quite a while. I have converted 2 1987 190D 2.5 Turbo's from automatics into 5-speeds, and on both of them, I have plugged the vacuum line that would normally go to the transmission.

This line originates at a blue plastic "pancake" style cylinder/can that is mounted on the firewall between the engine and the brake booster. I think it has 4 vacuum lines going to/coming from it.

I am having some other vacuum problems with my latest conversion, and I suspect that this blue cylinder is part of the problem. If this canister is only for the purpose of controlling the auto trans vacuum signal, I will completely bypass it. (The car has a manual trans now)

If it serves other purposes, then I'll do something else. Any help would be appreciated.

SteveM.
__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner
Reply With Quote
  #2  
Old 07-04-2008, 01:33 PM
280EZRider's Avatar
No Dumping
 
Join Date: Jul 2007
Location: Medford, OR
Posts: 1,444
Couldn't this be a check valve for the vacuum line to the A/T modulator?
__________________

Don't Chrome them; polish them
Reply With Quote
  #3  
Old 07-04-2008, 02:02 PM
TheDon's Avatar
Open Discussion Moderator
 
Join Date: Oct 2005
Posts: 13,208
I was told its a vacuum amplifier.
Reply With Quote
  #4  
Old 07-04-2008, 02:35 PM
Registered User
 
Join Date: Dec 2003
Location: Festus MO
Posts: 762
Amplifier.

I can believe that it might be a vacuum "amp". It's about 3 inches or so in diameter, and has 2 vacuum lines on the top (one clearly marked "Vac", and the other marked "tra" I believe). Then there are 2 more vac lines on the bottom of the device.

There is also a separate check valve, but it is only in the line from this blue device to the tranny.

SteveM.
__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner
Reply With Quote
  #5  
Old 07-04-2008, 02:45 PM
TheDon's Avatar
Open Discussion Moderator
 
Join Date: Oct 2005
Posts: 13,208
its actually a pressure converter
Reply With Quote
  #6  
Old 07-04-2008, 03:08 PM
Registered User
 
Join Date: Dec 2003
Location: Festus MO
Posts: 762
Any more info?

TheDon:
Any more info? What pressures does it convert? Is it only for the purpose of creating a vacuum signal for the auto trans?

SteveM.
__________________
'93 190E/D 2.5 Turbodiesel 5-speed (daily driver)
'87 190D 2.5 Turbo rustbucket - parts car
'84 Dodge Rampage diesel - Land Speed Record Holder
'13 Ram 2500 Diesel
'05 Toyota 4Runner
Reply With Quote
  #7  
Old 07-04-2008, 03:20 PM
Jeremy5848's Avatar
Registered Biodiesel User
 
Join Date: Mar 2006
Location: Sonoma Wine Country
Posts: 8,394
It combines pressure (turbo boost) and vacuum (from the vacuum pump via the vacuum control valve on the IP) to create a vacuum signal that mimics what the vacuum in a gasser's intake manifold looks like depending on load and throttle position. This allows Mercedes to build one tranny for both gassers and diesels. With a manual transmission you don't need the blue "flying saucer" and can remove it, carefully plugging the appropriate lines to prevent leaks.
__________________

"Buster" in the '95

Our all-biodiesel family
1995 E300D (W124) . .239,000 miles My car
1996 E300D (W210) . .313,000 miles Wife's car
Santa Rosa population 170,685 (2012)
Total. . . . . . . . . . . . 722,685
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970
Reply With Quote
  #8  
Old 07-04-2008, 03:24 PM
sixto's Avatar
smoke gets in your eyes
 
Join Date: Jun 2000
Location: SF Bay Area
Posts: 20,759
Check the vacuum diagram sticky. Maybe you can deduce it's function by how the vacuum lines are routed. Should be a similar arrangement in the 86-87 SDL and 87 D/TD if there isn't a 201 diagram.

Sixto
87 300D
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 10:10 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page