300D 1983.

I seem to have some vacuum issues and was hoping someone could point me to the right page here. (searching for Vacuum doesn't help).

Is there a simple way in the engine compartment to isolate the various parts of the vacuum system in order to isolate the leak? I know that the climate control, locks, brakes, fuel delivery, and transmission all operate off this system.

Issues:
Door locks worked two days ago, now after letting the car sit for a few hours, all the door locks do not open.

Poor fuel delivery - car surges at low speeds (slow/fast)

Transmission is shifting poorly.


I know when everything is working well on the car, it does none of things and runs really strong.

Thanks
Doug

PS. I thinks its the EGR valve, has a rubber hose that a hard plastic vacuum hose goes into. The rubber hose is falling apart. What can I replace that with?

It sounds like something has just come loose if virtually everything isn't working...

The in built search function is not very good.

Try something like this in google

vacuum door lock site:peachparts.com

Otherwise you'll see many vacuum related threads in the DIY section

PeachPartsWiki: Do It Yourself Articles - Mercedes Vehicles

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Do you have a Mity Vac tool?

When you turn the key off, does the engine shut down as it should? (there is a vacuum actuator on the IP)

The fuel filler vacuum pod was the weakest link in the system.

__________________
DO IT RIGHT THE FIRST TIME, DON'T BE A HACK
Political Correctness is NOT part of my vocabulary
and finally FIGHT CRIME...SHOOT BACK

'82 240D Stick
'85 300D Auto
Drove my first MB at age 16 1960 300SL W190

Everything shuts down fine. What is the fuel filler pod?

I would pick up some vacuum hose from the parts store and replace the EGR line. Then do a visual inspection of everything you can see.

I had vacuum woes on my SD and found that this helped me isolate the different circuits:



Those little black "spider" deals get old and leaky and they don't improve after manipulating them during troubleshooting.

Good luck! Since everything was working before I'm sure you'll find it's something simple!

__________________
My occupational hazard bein'
my occupation's just not around...
1980 300SD
1980 300SD

Start by measuring the vacuum at the main line with the Mity VAc. If the vacuum is ok at the main line with the engine running, your vacuum pump is ok. You then need to pull a vacuum on the yellow line and then the green line. Yellow is locks, green is climate control. Pull the vacuum and see if it holds. You should get an answer with those three tests because it appears the shut-off system is fine if the engine is shutting down ok.
I'd check the lines that go the Vacuum Control Valve to control the transmission on top of the IP, since if you are getting hard shifts, you have low vacuum in that system.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

If I were to put a vacuum gauge on the system, how much vacuum should I see normally?

__________________
Own:
1970 Mercedes 250c, 1976 International Scout II, 1982 Mercedes 240d, 1997 Honda Accord Wagon, 1998 Acura Integra Type-R, 2009 Mazda5.
Owned:
1974 International 100 pickup, 1975 International Scout II, 1981 Mercedes 240d, 1985 Mercedes 300SD, 1988 Honda Accord, 1988 Ford Thunderbird, 1991 Honda Accord, 1996 Geo Metro, 1996 Ford F150, 1996 Dodge Grand Caravan, 1997 Honda Accord, 2003 Acura TL-S, 2003 Yamaha V-star.

Around 21 inches at sea level. Lower at higher elevations.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Here is a list of vacuum diagrams.

http://www.peachparts.com/shopforum/diesel-discussion/105297-vacuum-diagrams.html

http://www.peachparts.com/shopforum/diesel-discussion/160169-w123-vacuum-interlock-diagram.html


I doubt your EGR even works, probably plugged solid.
Charlie

__________________
there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

For the 83, the best place to start checking is on the engine side of the firewall by the brake booster. Everything branches from there.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Search function here could be better, but isn't that bad if you do an advanced search (I never use the basic search function). The basic search will search the whole content of all posts for the keywords you enter. If you do an advanced search you can narrow your keyword search to just titles, which is what I always start with and usually have success finding what I need (just have to think about how others will title threads related to the topic of interest). You can also tailor you search in other ways as well and sort the result in different ways.

I believe the search here is limited to returning up to 500 results, which is what you get if you search those words. A google search of those criteria returns over 10,000 links. A forum search (titles only) returns 29 results.

The key is picking the most relevant search terms, which sometimes involves thinking like other forum members. Of course, if you've been around long enough, you can also search by member if you know who probably has the answer you need.

Also if you use parentheses to bracket words you can search phrases. Whereas a search of the words "fuel" "hard" and "lines" will return a bunch of threads that just contain those words someplace in the text, a search of "fuel hard lines" will return far fewer threads that actually contain those three words together.

To me, the worst part of the forum search is the 20 second wait between searches, what's the deal with that anyway? Sometimes I want to try a phrase, but if I don't get what I want I would like to go back and try something else . . . . but you end up waiting until it's okay to search again. 15 or 20 seconds doesn't sound like much, but in the age of high-speed information, it is nearly an eternity.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

I built a custom thread with diagrams and pics combined. It may not be exact for your car if it's a Cali model. The diagrams are also for a coupe, so they have an extra line for the seat backs. http://www.peachparts.com/shopforum/diesel-discussion/295616-definitive-83-fed-300cd-vacuum-thread.html

Generically in the engine bay green is climate control, yellow is locks, white (light gray)is the engine. Check valves may/may not isolate these systems depending on whether the engine is running or not.

Uber-basic troubleshooting may be simply playing with the AC controls: do the symptoms go away in OFF, in DEFROST, etc. You may be able to isolate a leak there.

A to Q. from above: Fuel filler pod refers to the vacuum pod that activates the pin in the door over the fuel cap. It's connected to the locking system (yellow lines).

Where did you find the 5 way and the 4 way in the photo? Looks like a neat replacement for the black ones.

__________________
Joe

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1980 300SD - 495k miles - 'The Ambassador'
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Former Family Members
95 C280
73 280SEL
90 300D
87 300SDL (X2)
86 560SEL
84 300D
80 300SD

Here ya go Joe:

List: Vacuum Connectors - Straight | O'Reilly Auto Parts

I think they were in the "HELP" section near the rubber vacuum caps.

In this pic I vave the vac hooked into the blocked off port (for the gauge) and a vacuum pump made from a breast pump and some radio shack bits hooked up where the engine vacuum pump supplies vacuum.



It works well for troubleshooting vacuum stuff with the engine off. A better option would be a Ford truck electric vacuum pump but they are about $100.

__________________
My occupational hazard bein'
my occupation's just not around...
1980 300SD
1980 300SD

I have dumb question. In the picture on the 4 way vacuum splitter, there are pieces of black hose that accept the Mercedes hard vacuum hoses. What are these black pieces of hose called and where can I get some? My EGR adapter hose is frayed beyond, so that vacuum hose keeps popping off.