Please Help: Vacuum Issues
 

I just bought a 1983 300cd and I have convinced myself, after much research on this site and the internet, that the vacuum lines on the car are not currently hooked up right. I am having shifting issues, etc. Some of them are probably not vacuum related but from everything I have read this is the place to start. I can't seem to find anywhere a vacuum diagram that matches the setup in the car. Some aspects of what I have found posted are correct but once the lines hit the vacuum control valve i'm guessing. Can anyone lead me to proper vacuum diagram routing for this model car? I have a 5 way splitter off of the check valve that is confusing me the most. I beleive I know where everything goes off of the seccond orifice, down to the dashpot to the vacuum control valve. to the transmission line. I just need some help.

One invaluable tool you will need is a MightyVac.

Mine came used from ebay at about 15% of new price.

If you don`t get it ironed out, bring it to the GTG May 22.

http://www.peachparts.com/shopforum/diesel-discussion/275432-northern-california-drive-may-22nd-roll-call.html

this site might be of some help

http://www.peterschmidtransmission.com/vacuum.htm

Charlie

Another link
 

This one was helpful for me if you are troubleshooting the side that goes to the door locks:

http://ericandkat.com/mercedes/W123VacDoorLockDiag.JPG

Also if you look under the front carpets, driver and passenger side, you can see where they split off and go to the various actuators in the doors, gas flap and trunk -- isolating each branch and using the trusty MityVac is a helpful way to do it.

-Chuck

Vacuum diagrams
 

Here's what I found when I did a search here(hint, hint;))

http://www.peterschmidtransmission.com/vacuum.htm

See: http://www.peachparts.com/Wikka/Trans722VacModhttp://www.peachparts.com/Wikka/Trans722VacMod for how to check if the trans is adjusted correctly.

The five way splitter goes to the HVAC (green, probably), ignition shut off (brown), door locks (yellow check valve) and seat back lock (blue).
On the top of the VCV one line should go to the transmission, that's all I have as I've bypassed the egr. The line coming from the side of the VCV is a vent line that goes to the cabin.

I think all the lines are going where they should. Now the car won't downshift to first. It also has the 2-3 flare but it had that before. I guess I need to get that vacuum pump and look for leaks. Any other ideas.

Defiantly check to see if transmission modulator will hold vacuum. If it does not hold vacuum, check the cap on the modulator and replace if needed.

what todd said. Also, buy a 3 way splitter (commonly found at just about any autoparts store). buy the right size and buy some extra tubing thats long enough for you to run it into your cabin with your mityvac. tap into the line going to the transmission modulator. at idle, you should have about 13" to 15" HG. that should go down to close to 0" as you press on the accelerator pedal. it has an inverse relationship to rpm.

One of my '83s had a bad 2-3 flare when I bought it. I was prepared to start sorting out the vacuum issues. A simple adjustment of the Bowden cable put it in back in the groove. I wish everything was that simple.

OT, sorry, but you have an 82, would you be so kind as to inspect the secondary fuel filter head and let us know the part number? Specifically the circled number.
Thanks.