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  #31  
Old 01-15-2008, 01:57 AM
Craig
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This would be the diagram that would help, but it appears to be out of service at the moment:

http://home.comcast.net/~phantoms/vacuum/fuel_egr_240d_manual.jpg
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  #32  
Old 01-15-2008, 02:05 AM
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the line that goes to the electric switch on the right fender then proceeds to the firewall. the line that goes from the thermo switch to the electric switch on the fender enters the top and then there's one black vacuum line leaving the switch to the firewall. i don't see any lines that might be coming off the top of the engine directly to the thermo switch. the line that goes from the thermo switch to the egr ends there. i don't see any more lines near the egr.

can someone identify the components in this picture for me? it would really go a long way towards deciphering what i'm looking at.
http://www.peachparts.com/shopforum/attachments/diesel-discussion/17426d1081619744-pictures-vacuum-diagrams-w123-w126-diesels-vacuum-6-240d-man-trans-diagram.gif
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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP
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  #33  
Old 01-15-2008, 02:16 AM
Craig
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Good, that helps:

6 = the box on top of the valve cover containing vacuum valves (controlled by throttle position)

15 = your broken thermo switch

7 = switch on right fender

9 = EGR (under air filter)

That diagram appears to agree with my car. Do you have that box (#6) on your valve cover with 3 vacuum lines and the throttle linkage connected to it?
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  #34  
Old 01-15-2008, 02:40 AM
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i have that. but the line that looks like it's supposed to go to the thermo switch from the throttle piece, instead leaves the throttle piece and couples into a black line by itself that goes directly through that big junction at the firewall on the driver's side. what's more, the electric switch has only two lines connected to it. it's missing the line that goes to the egr. the junction on top of the throttle also has an additional black line coming from the number five position that meets at a "t" with the other black line coming from the number 2 position on that same throttle piece. that "t" is connected directly to a little white plastic module that sits on the fuel injector. on the other side of that module is a brown line with a blue stripe that then goes to that big junction at the firewall

the white line coming off the number 1 position on the throttle goes directly to the check valve in the main vacuum line between the vacuum pump and the power brake module (without going through the "T" first like in the diagram)

this is starting to seem really wrong to me.
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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP

Last edited by mechanicalman; 01-15-2008 at 02:43 AM. Reason: clarity
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  #35  
Old 01-15-2008, 02:59 AM
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allright, if someone can identify the rest of the crap in that vacuum diagram picture, i'm going to take some good clear pictures of the elements in my vacuum system and post them with descriptions of what's connected where and how, because my descriptions just aren't cutting it. everytime i peak at it and post, i notice something else that looks abnormal. i'll have to wait until tomorrow to post though because my camers has a really lousy flash.

i already owe you guys a lot.
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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP
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  #36  
Old 01-15-2008, 09:30 AM
Craig
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I agree, it doesn't sound correct, this diagram has all the parts labeled:

http://home.comcast.net/~phantoms/vacuum/fuel_egr_240d_manual.jpg
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  #37  
Old 01-15-2008, 10:03 AM
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Quote:
Originally Posted by mechanicalman View Post
allright, if someone can identify the rest of the crap in that vacuum diagram picture...
1 is the mechanical switchover valve on the valve cover, operated by accelerator, prevents EGR operation at closed throttle by venting vacuum
2 is the vacuum control valve on the injection pump
3 is a vacuum surge damper
4 are three-way connectors
6 is the connector for the mechanical switchover valve (#1)
7 is the electrical switchover valve. It vents vacuum when speed is above 46mph and/or engine rpm is below 1300 to prevent EGR operation under those conditions. It is controlled by the EGR control unit (not shown in the diagram) in the cabin, located in the passenger footwell.
9 is the EGR valve
11 is the EGR valve duct
15 is the thermo valve, which prevents EGR operation whan coolant temp is below 17C.

The black vacuum lines are vent lines. The are usually routed into the cabin so they have a source of clean air. Don't be surprised when you discover that they connect to nothing!!!
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  #38  
Old 01-16-2008, 12:50 AM
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okay, guys. i'm getting to the bottom of this. it looks like the egr was already disconnected. the line that would normally go from the mechanical switchover to the thermo switch just couples directly to the black vent line that goes through the firewall on the passenger side. meanwhile, there's an extra black line coming from the number 5 position on the mechanical switchover valve that connects to a three way with the other black line coming from the mechanical switch at the number 2 position right before they both enter the vacuum control valve on top of the injection pump.

finally, the white line coming from the number one position on the mechanical switch just connects directly to the front most connector on that little check valve looking thing that sits right on the main line coming from pump. does that all sound right?
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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP
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  #39  
Old 01-16-2008, 01:12 AM
Craig
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Quote:
Originally Posted by mechanicalman View Post
the line that would normally go from the mechanical switchover to the thermo switch just couples directly to the black vent line that goes through the firewall on the passenger side.
That doesn't sound OK, it seems like having that line vented would cause a vacuum leak. I would plug that line.

Quote:
Originally Posted by mechanicalman View Post
finally, the white line coming from the number one position on the mechanical switch just connects directly to the front most connector on that little check valve looking thing that sits right on the main line coming from pump. does that all sound right?
That main line is the vacuum supply to the entire system. Plugging that line should take the "mechanical switch" completely out of service and eliminate any leaks there. If you can plug that white line without affecting the transmission shifting, you will eliminate lots of potential leak points. I would give that a try and see what happens.
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  #40  
Old 01-16-2008, 01:23 AM
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Quote:
Originally Posted by Craig View Post
If you can plug that white line without affecting the transmission shifting, you will eliminate lots of potential leak points.
Impact on a manual transmission should be....minimal. Very minimal.
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  #41  
Old 01-16-2008, 01:28 AM
Craig
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Quote:
Originally Posted by tangofox007 View Post
Impact on a manual transmission should be....minimal. Very minimal.
Duh, I forgot we were talking about a manual.

Yup, try blocking that white line. Hopefully that will isolate the vacuum leak, at least it will narrow it down.
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  #42  
Old 01-18-2008, 08:16 AM
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okay, i tried pluggin the line coming off that first check valve that's supposed to feed the central plug on the mechanical switchover valve. when i took the line out, the rubber coupler sucked on the tip of my nitrile glove, so i can confirm vacuum, but it seemed kind of weak to me. after plugging the line with a nail that fit just right, i went into the car and tried operating the locks with the engine running. they all worked a few times but seemed really lethargic. more exciting though, when i turned the key the engine shut ITSELF off, instead of having to use the choke switch in the engine compartment! happy day!

i tried to replicate all this. when i tried operating the locks with the engine running, the locks only responded once. when i took the nail out, there was no longer any vacuum. when i turned the key, the engine remained running. i waited awhile and tried starting it again. there was vacuum, but it seemed really weak like before.

i'm going to guess that my vacuum pump is failing. any seconds? it's important to note that i don't have anything to compare and tell me if the vacuum is weak or not, i just thought that it should have been stronger.
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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP

Last edited by mechanicalman; 01-18-2008 at 07:48 PM.
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  #43  
Old 02-08-2008, 03:28 AM
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Found!

Alright, so I finally got my vacuum pump from northern tool. I started in the engine compartment and found that the leak was not coming from the main connector on top of the valve cover, neither was it coming from the reservoir or the shutoff valve. Great! It's something in the interlock system. I also noticed that the interlock system wouldn't only retain vacuum if the main switch at the driver's door was in the 'lock' position.

At this point i pulled up the floor mats in the driver and passenger side of the car to get at the four and three-way connectors. At this point is found that only the yellow/green line wouldn't hold vacuum, the "lock" lines if you will. After a lot of fiddling. I finally isolated the problem to the lock actuators in both rear doors. The fact that I had two leaks made tracking this down a lot more time consuming.

So to fix that, i removed both actuators from the doors and plugged the vacuum lines with golf tees. Now everything works like it should except for the cruise control (and the back door locks obviously).

The part that actually failed was the thin little boot around the plunger. Both actuators failed the same way. Each had a single little tear in them. New actuators look like they'll cost about $30 a piece. Can you guys tell me if there's anyway to just replace/repair the boot or am just going to have to buy new ones?

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1983 300SD Grey on Grey 220,000 miles

if i'm asking for a part/maintainence/repair information, assume i'm asking about the car above.

1982 240D Manual Trans. RIP
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  #44  
Old 02-08-2008, 05:02 AM
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if there is a pick n pull nearby you can get those for probably 5 bucks a piece
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  #45  
Old 02-08-2008, 05:10 AM
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I once repaired a vacuum dashpod with a bicycle tire patch. But the surface of these are ribbed, which makes them more difficult to patch. If you can find a realy thin type of rubber patch, and just put alot of pressure on it when its glueing, it should seal. Or maybe just find some realy thin rubber, and super glue it over the rip.
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