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  #1  
Old 09-04-2004, 07:33 PM
webwench
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Questions about my w123 1985 300D... what the heck is this stuff?

After referencing my Haynes manual, I'm still unable to determine what these are/where they go. Can you point me in the right direction? (If the images are problematic on the forum, they are also posted here.

First, in the front right portion of the engine compartment, I have a couple of wires/leads that are loose, but clipped down. What are they, and should they be this way?


Secondly, here is a thing between the fuel filter and what I think is the power steering pump. It is labeled VDO and the throttle linkage links up to it. It was making a funny noise today when I was trying to start the car up for the first time in a few days, sort of a electrical clicking rattle. However, once the car started and ran a bit, the noise disappeared. I wondered what this is and why it would make such a noise.



Finally, after changing the oil, which entailed kind of manhandling around some various vacuum lines and such to get at the oil filter housing, I now have a black line, maybe a vacuum line and maybe not, which is floating around not hooked up to anything on one end. The other end is hooked up via a black boot to this yellowish part, which seems to be part of the fuel injector pump. The car runs (exceedingly well, actually), but I am concerned about this line. What is it for, and what if anything should it be connected to at the other end?


Any help would be very appreciated. The car is running great with fresh oil, new fuel filter and prefilter, and air filter, but I'm obviously still learning the basics.

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  #2  
Old 09-04-2004, 07:45 PM
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#1 Possibly to the alarm horn. The connectors are after-market, not MB.

#2 That is the cruise-control actuator.

#3 Can't tell from your picture.
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  #3  
Old 09-04-2004, 07:45 PM
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It looks like those wire leads in the first picture are for the electric auxilliary fan. They're supposed to plug into a sensor on the a/c drier (the black piece with the hoses and the other electrical connection), and is supposed to turn the fan on when the refrigerant gets too warm.. From the picture, it looks like the sensor's missing...does your a/c work? I'm guessing not; IIRC it's impossible to remove that sensor without draining the system...

Quote:
The connectors are after-market, not MB.
Actually, unless hers and my car were worked on by the same person at some point (or there's a really eerie coincidence somewhere), those are factory. I agree that they don't look like M-B (don't know about you, but I've never seen that connector anywhere else on the car), but I've got the exact same connectors on my '85...and, BTW, I actually jumped these two wires to get my aux fan to spin whenever the key's on (because my engine-driven fan's temporarily dead).

The second and third pictures are of your cruise control actuator. This is what physically moves the throttle linkage (that's why it's connected) where the CC brain box tells it to to maintain speed. Given the corrosion on the outside, I would imagine that it's bad...

The fourth picture...if you're referring to the line at the lower side (as opposed to the oen on top), mine goes through the firewall into the passenger compartment. I've been blessed in not needing to play with the vacuum system on my car all that much, so that's all I can offer there...sorry.

Hope this helps some...good luck!
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Last edited by The Warden; 09-04-2004 at 07:50 PM.
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  #4  
Old 09-04-2004, 07:46 PM
JMH JMH is offline
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what is this stuff?

Webwench,
First of all, I am very impressed that you are doing your own work! I love doing my own stuff... most people think I'm crazy for doing so much of mine on my own!

The wires hanging down there, I don't remember that on my 84 300D but the other items, the VDO part, goes to your Cruise Control. You could disconnect the linkage that goes over to it and disconnect the electrical wires to it and you'd be fine. The black tubing coming off of the injector pump I believe is the vacuum system vent tube that usually goes through the rubber boot of your firewall and vents to the cabin..... it is easy to pull that piece or other vacuum lines loose or out when changing the oil... would seem Mercedes could've designed a better way to get the vacuum lines routed around the Oil Filter housing.....

I have a crude diagram of the 1985 model vacuum routing (A close friend of mine bought a 1985 and since I help him fix it when needed, the vacuum was a mess on his when first purchased.

Let me know if you need more info....... as for those wires, you might check to what branch of the wire harness they come out of and then check your schematic in the Haynes manual in the back schematic section.....

Good luck and I hope this helps!

JMH
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  #5  
Old 09-04-2004, 08:05 PM
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Quote:
Originally Posted by The Warden
I agree that they don't look like M-B (don't know about you, but I've never seen that connector anywhere else on the car), but I've got the exact same connectors on my '85...
All the courtesy lights on the doors of W126s and the dome lights (above rear view mirror and the one in the back center or the rear windshield) have the same connector.
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  #6  
Old 09-04-2004, 08:24 PM
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First Picture

The connectors in your first picture are supposed to connect to the temperature switch on the AC Dryer...These are standard Mercedes Connections and are the same on the 116, 123 and the 126 Diesel Turbo's..This temperature switch is removeable without draining the system...if you want to remove or exchange the pressure switch on the dryer then you must bleed the system....If your AC is not working then you need to see if your clutch activates on the compressor by pulling the other 2 wires from the dryer and touch them together when your engine is running...this is just a test and remember to put the wires back on the same terminals on the dryer...you can test your auxiallary fan by tracing the wires from the fan and disconnection them at the connector..use 2 jumper wires from the battery...if the fan works then reconnect the wires back to the connector and then connect the 2 wires in your first picture to each other..The fan should work...all of this should be done while your engine is running...if the fan works then you can wire the 2 wires in the first picture back to the temp. switch on the dryer...the most you can do is maybe have them on backwards...the auxiallary fan should not come on unless the system is pressurized(Heat activates the temp. switch) when these 2 wires are hooked up and the clutch on the compressor will not work unless the system is pressurized and it gets 12 volts from the pressure switch on the dryer....I will look at your vacuum system but your picture does not show me enough but I will look....JIm Harris
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Old 09-04-2004, 08:25 PM
webwench
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Quote:
Originally Posted by The Warden
It looks like those wire leads in the first picture are for the electric auxilliary fan. They're supposed to plug into a sensor on the a/c drier (the black piece with the hoses and the other electrical connection), and is supposed to turn the fan on when the refrigerant gets too warm.. From the picture, it looks like the sensor's missing...does your a/c work? I'm guessing not; IIRC it's impossible to remove that sensor without draining the system...

...The second and third pictures are of your cruise control actuator. This is what physically moves the throttle linkage (that's why it's connected) where the CC brain box tells it to to maintain speed. Given the corrosion on the outside, I would imagine that it's bad...
Thank you very much. You're right that the cruise seems not to work (either that or I just don't know how to operate it )... either way, i don't feel the lack, and now that I'm enlightened, maybe I'll just disconnect it from the throttle linkage entirely?

The AC oddly enough does work, blowing coolish but not cold. I will investigate the missing sensor further, thanks much.

JMH, don't be too impressed, you should see how badly I botched the oil change I'm very glad for this forum, though, I've spent hours reading it and probably learned more than I could from devouring the Haynes manual in its entirety.
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  #8  
Old 09-04-2004, 08:39 PM
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Auxiallary Fan

If your fan is not working the AC system will not get as cold as it will with the fan working..It can make a 10-15 degree(and maybe more) difference...You can test your fan by jumping it direct from a battery and if the engine is running and your AC is on you will feel an immediate difference in the AC Temperature in the car...If you do not feel any difference in temperature then your systems charge is low..Maybe not much but is does not take much to create a big difference in temperature..JIm
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  #9  
Old 09-04-2004, 10:20 PM
123c
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I see that your car is missing it's 'Cigar Hose', which is the return line which goes from the top of the fuel filter housing toward the firewall. It is important that you use the cigar shaped hose, or you might run into some problems down the road, or that's what I have been told...
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Old 09-04-2004, 10:30 PM
webwench
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Quote:
Originally Posted by 123c
I see that your car is missing it's 'Cigar Hose', which is the return line which goes from the top of the fuel filter housing toward the firewall. It is important that you use the cigar shaped hose, or you might run into some problems down the road, or that's what I have been told...
Thanks, Eric. I will look for more info on that, and replace the hose. Should the return line terminate anywhere in particular?

Quote:
Originally Posted by jim16671836
You can test your fan by jumping it direct from a battery and if the engine is running and your AC is on you will feel an immediate difference in the AC Temperature in the car...
Thanks Jim. I'm going to do as you say and report results.
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  #11  
Old 09-05-2004, 12:26 AM
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the black vacuum hose coming off the back of the ip is a vent hose; it is open.
the cigar hose goes from the top back of the cannister fuel filter where you have a 3/8" (?) hose and is used to releive pressure surges in the fuel return line.
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  #12  
Old 09-05-2004, 10:41 AM
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The yellow unit on the rear of the injection pump is a vacuum regulator, and should be tee'd to the transmission, the switchover valves on top of the valve cover, and the main vacuum supply. How does your car shift? beneath that little plastic dome is an adjustment. You'll notice that the regulator is also linked to the throttle. What happens is the more you push on the throttle, the more vacuum is bled off from the transmission, resulting in later and firmer shifts. When you are accelerating slowly without depressing the pedal much more vacuum remains resulting in earlier and smoother shifting. The line coming off the regulater should definitely go somewhere..

Here's a link to how the regulator is involved in the transmission adjustment process..

http://transmission.articles.mbz.org/adjust/
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Old 09-05-2004, 10:10 PM
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Webwench,

I can't help you any more than the others already have, I just have to congratulate you on doing it yourself.

I have some friends that just moved out to Atlanta and their 123 300D had transmission failure....if they had a friend like you out there, they might not have had to buy that sorry excuse of a rice burner they now call tranportation.

Interesting website, by the way. Some of your links are great!!

Was saddned to see that Mercedes Shop wasn't on your list of most used...maybe that'll change soon.

Good luck finishing up this job and driving the car!
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  #14  
Old 09-06-2004, 01:18 AM
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'doh

Your 'cigar hose' died an untimely death in a torrential downpour in New Jersey during my test drive. It had probably been leaking for some time, but it actually ruptured, so it was replaced at a truck stop. The p.o. did a temp fix with the line you see installed now. Since I was using biodiesel, I wanted to see for myself how the rubber lines would hold up, so I didn't go out and get a new cigar hose until after I ran the b100 for a while. Then, I got fixated on converting the car to SVO, and while collecting those parts decided the cigar hose would be replaced anyway, and so I didnt ever put it in. Naturally, I came across the SDL and decided to convert that car, and forgot about that cigar hose... sorry!

Those vaccuum lines over/around/under/on top of the oil filter housing gave me fits everytime. grrr.

Love your website, and it's fun to see the changes taking place! Glad she/he/it found a good home and a caring owner!
k

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