If youre missing the VCV, youre going to need to go junkyard diving for one. They are $196 new, and there is NO reason that they should be. Ive taken a few apart in my trials and tribulations and there isnt much to them.

To test, remove all of the vac lines and clip off the ball joint that connects the VCV to the throttle linkage. Try not to disconnect the plastic clip that attaches the VCV to the throttle linkage, I broke mine, and Im assuming you need this part anyway.

Attach your MityVac to the top port and pull the throttle connection down all the way. This closes the VCV.

Now pump up to 20 mmHg or so. With the rack closed, it can bleed vacuum up to a rate of about 2mmHg per second. If it passes this test, slowly push the VCV open, the vacuum should drop to zero as you go up.

Hope this helps, let me know if you need more clarification...

dd

__________________
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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

Noah - Thanks for pointing my failing mind!
So if the vacuum diagram you selected from the Peter Schmid WebSite is for your car, then you should have one of those $200 plastic Vacuum Control Valves (VCV). Both of our 1980 models [ 240D & 300D ] have the same one and I have verified that VCV(s) were first installed on these cars either late in 1979 or the early 1980 models... and most likely they were probably installed on the first 1980(s) models that rolled off the line and from then on.
On your car, who knows, your IP might have been changed... but on the chance you have the original IP or another just like it, look for the two mounting machine screw holes. That makes the most sense as to the first thing you should do. IF your IP has the holes, then DD is right, it's probably time to do some salvage yard diving! You are probably also missing the linkage for hooking the VCV to the throttle. And while you are salvaging, IF you happen to find one of the vacuum "dashpots" [a small plastic chamber], pick it up too for these were NOT installed on the 1980 models and it will help soften the 1-2 shifts. If you don't happen to find one salvaging, not to worry for you can purchase these for less than $5.00 OnLine. Take a look at a 1981, 1982, 1983 etc vacuum diagram on the PeterSchmid.Com WebSite and you will see they install on the top of the VCV.
See: http://www.peterschmid.com/vacuum/1977_1985/616_617_91/616_617_91.jpg where the "dashpot" is #72.
Regards,

Thanks you guys--

I could have made it clearer: there's definitely no VCV in the engine compartment, although there are some other parts in there that don't match the vacuum diagram. I will look for a VCV; it appears that it's the same part for different years, although it looks like it has different MB part numbers (?). The FI pump has four screws on the top, one in each corner--no extra for the VCV--I assumed the VCV would mount on two of these. I'll try to find another (more complete) Benz to get an idea what should be going on.

If the VCV isn't the same part for different years (and different transmissions) it'd be great to know before I go shopping.

Thanks!
-noah

__________________
1980 300D (non-turbo, 421k miles)
1984 300TD (turbo, 305k miles)
1985 Vanagon (170k miles)

I scoured a large variety of VCV's during my hunt. The same VCV that was on my 82 300D was also on W115 chassis 300SD's, W126 SD's, W123 240d's and of course all 300D's that I saw. A local yard 79 240D I have seen had the exact same VCV as my 82.

I think theyre all the same...I think. If you know a local MB parts place they will be able to tell you the part for your year and match it to the later models to verify.

dd

__________________
-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

I went out and got a MBZ p/n off my old VCV - 1230700046, and then did a new part's source search including this FORUM's sponsor and came up with price$ that vary from $166 down to $110.
I also have some hi-resolution pics of how this VCV mounts on both my 1980 240D and my Son's 1980 300D [they both use the same VCV]... and I can share the new parts source info with you IF you will contact me via this FORUM's Private Mail or direct. More later... got to run!
Regards,

After checking out a friend's W126 and orienting the VCV mount, I've determined I don't have the same kind of VCV mount on my FI pump--see attached. Off to the junkyard.

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__________________
1980 300D (non-turbo, 421k miles)
1984 300TD (turbo, 305k miles)
1985 Vanagon (170k miles)

It's CRITICAL... how you set your transmission's vacuum system on your diesel MBZ...

Incorrect vacuum to the transmission will cause differential wear over time. This is what occurs after years of no vacuum and hard shifts.

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Thanks for the input for this is a somewhat different slant on this subject of setting up the vacuum shifting systems for these AutoTrannies!
Regards

Hey fellers -- just to add to the confusion, I have a 1980 Euro 300D. No EGR, thus a very different 3-2 valve arrangement (just one valve, so I'm not real sure what you'd even call it). Three lines go to this valve arrangement, and one of them goes straight to the transmission, with no little green dashpot that I can find. My transmission flares and shifts early, and I'm not really sure where to start, even. I do have a MightVac. Anyone mind taking a look at some pics if I can shoot a couple? Thanks in advance!

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Despite the fact your 1980 300D is a Euro model, maybe we can help you out... but first we need some further clarifications:

Q1 - Have you looked at what I believe is going to be the closest "Engine/tranny" vacuum diagram we are likely to readily find... the diagram at: http://www.peterschmid.com/vacuum.htm: and then: http://www.peterschmid.com/vacuum/1980/617_912.jpg ?

Looking at this diagram, identify for us each of the numbered vacuum components that you actually have on your 80' model 300D Euro MBz... e.g. I believe what you call the 3/2 valve is shown on this diagram as #64 and called a "Switchover Valve" and is on top of your valve/cam cover. PLEASE identify [from this same diagram] every component that you have... by #___ & "name" as shown in the diagram. We need this supplemental information for we could spin a lot of wheels [not to mention minds] needlessly.

While you look at this diagram, also NOTE #63 a small "orifice" and #62 a plastic Tee also shown as an "orifice". IF you have read the earlier POSTS on this somewhat lengthy THREAD, you will know that I'm big on the subject of these restricted orifices which I believe were MBZ's way of doing the final tuning of the vacuum control systems on these vintage diesels that had automatic trannies.

Q2 - You did indicate "flares" which usually means you must have an auto tranny!??

Yes, I will take a look at any pictures but please first go through the I.D. drill I have requested above.

A final question that should be included in the above I.D. drill:

Q3 - Are you telling us you do not have a vacuum control valve [VCV] which is incorrectly shown as a "vacuum modulating valve"?

Yes, you will see some of these vintage cars' vacuum components with names that are NOT what we in the U.S. know them as!!
Regards,

Thanks for the reply, Sam. To answer your questions:

1. Yes, I looked at those diagrams, and the print is too fine on my laptop to read. When I save it to desktop and try to increase it, the font is just blurry. I'll post pics of what I have, but there is *no* EGR, and what appears to be the 3/2 vavle on other engines (the two valves on top of the valve cover, under a black plastic cover) consist on ONE valve on my car. I took a pic of this. The line coming off from the far side, making a "U" back toward the driver's side of the engine compartment, appears to be the line to the tranny. The two going into the "switchover valve" from the driver's side run down to the IP. There is no green dashpot in it that I can see. Yes, I did see your comments on the orifices and suggestions against drilling them out; the car is new to me so I cannot speculate on whether or not that (or anything else) has been done to it.

2. Yes, automatic transmission, of course.

3. Yes, if I understand correctly, the VCV is the green dashpot, correct? I see none.

Thanks again!

Chris

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__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

Chris,
I have been assuming your Euro 300D is the smaller W123 chassis, NOT either a W116 or W126 model, both which would be the equivalent of our 300SD models. So:
Q1a - Which is yours?
Q1b - Does your engine have a turbocharger?

As to your 3/2 valve... I looked around and the triple-connection vacuum switchover valve you show is what I know and see at parts WebSites as a "3/2 valve". Only the 1980 W126 300SD models have a double [2 separate] valves arrangement. Seeing all three of your connections on your 3/2 valve in use is a bit unusual for our 1980 300Ds and 240Ds that are both W123 chassis only use two of these and this is born out by the diagrams you are having trouble seeing and/or reading.

Your center photo shows what appears to be a VCV [a VCV is not the same as a dashpot ]... well this photo raises more questions than gives answers. First, the 1980(s) models W123 chassis delivered in the U.S. did NOT have a green dashpot at all so don't worry for now about there not being one there. What I see as possibly a strangely located VCV, this device has a " Y-shaped " vacuum connector on top of it and I must assume that the black w/green striped vacuum line that comes down from above to one side of the " Y " comes from the 3/2 valve up above.
Q2 - Where does the 2nd vacuum line go that is connected to other [right side in photo] branch of this " Y " connector?

Q3 - Why don't you try a little "Simple Green" or other degreaser spray solvent and then wash off some of the "GUCK" !?

For future reference, it appears to me that your IP [injection pump] appears to be a " MRSF " type ... and it appears that just maybe you have a vacuum line attached to your " ALDA " on top of the IP

Hi Sam -- yes, my new car is a 1980 300D (thus W123 and normally aspirated). Sorry for the lack of detail! Yes, the green/black line goes to the valve. The other line you see coming from the "Y" that the green/black line shares runs up to another junction, which is visible in the last pic. It's the line running up just in front of the filter housing in the pic. You can see that it attaches to a connector that is fed by the main line from the vacuum pump, and also feeds the lines that run through the firewall (door locks and whatnot, I presume).

As for the gunk... I just got the car Friday morning, about 5 minutes before I left for work. I was gone all day Friday and again all day today, and it's near freezing to boot... so I have yet to wash the car at all, let alone detail the engine! Sorry for the dirt and grime in the pics; I know it doesn't help identifying details! Tomorrow I'll take a better pic of the lines near the ALDA/IP. It's certainly different than any other arrangement I have seen, I believe!

Thanks again,

Chris

__________________
1992 300D 2.5T
1980 Euro 300D (sadly, sold)
1998 Jetta TDI, 132K "Rudy"
1974 Triumph TR6
1999 Saab 9-5 wagon (wife's)

I now believe that what I thought was an ALDA on top of your IP is probably the IP's round vacuum actuated IP/engine shut-down device... and the vacuum line that leads to this device comes through the firewall from the ignition switch.

I have also made out what looks like a restricted orifice between the " Y " connector and what I believe is your VCV on the left side of the IP [ an unusual location for VCVs].

Regards,

Chris/cscmc1,
Q1 - Is this the same car we are talking about?:
http://cgi.ebay.com/ebaymotors/Mercedes-Benz-300-Series-Mercedes-300-1984-Mercedes-Benz-300D-Magnificiently-Priced_W0QQcmdZViewItemQQcategoryZ6330QQihZ013QQitemZ230113670135QQrdZ1QQsspagenameZWDVW

Q2 - IF you answer yes to Q1, do you think it really has a new tranny?

As a "Euro" car, we might have some difficulties working out this engine/tranny vacuum control system. I believe you will not only have to do a lot of cleaning, but because it is a "Euro" you should really document thoroughly with "pics" anything that you have to take apart for cleaning... this way you can use your photos to put things back... all the while realizing that something might not be correctly assembled as it is!

I'm particularly interested in what I'm all but positive is a Vacuum Control Valve [VCV... aka vacuum modulator valve in some diagrams] that is mounted on the left side of the IP. If this was my car, I would start [one at a time] start removing just such vacuum components to clean them thoroughly and pick off any P/N(s) I could find. Such info might just prove invaluable. I know proper functioning of this VCV is critical to the tranny's shifting and so IF the tranny is "new", then you might try to find out who did the replacement!

What is really puzzeling is that I have access to some old "MBZ of N. America" shop manuals that show this exact VCV and it appears to be on a 617.91 series engine. I see you have been shopping around for such a diesel for some time... can you confirm for us the VIN and other specs for this car? So you might luck out and find many of the parts on these "Euro" models are the same as on U.S. delivered cars... let's hope so!

Regards,