OK Mike - my hands are dirty ... I've been playing This Old House and This Old G for the last 6 months here in Houston I just need to get my bearings on the vacuum line location ... Is the thing in the below pic right in front of the Distributer?

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Things always look easy after the fact...I spent hours researching, feeling and asking questions.  Also much time cleaning all the grease from my hands.  In addition, it is not easy to get to but there is a way, without taking things apart.  I got to a point where I could plug in lines and hoses where they go without even looking.  Bram was a big help with his photos which I looked at for hours trying to picture in my mind how things actually work.  Sorry if I gave the impression it was a slam dunk...it kind of is, once you know how all the other stuff works and how to get to where you need to be.

Good Luck....it will come togther soon.

Mike

I am sure it is easy - It can't be that hard as there are only 2 wires and a few vac lines and some screws! It is only my ignorance that is frustrating, not your helpful direction. Also, who knew that besides the stuff the federalizer put on yours, Mercedes added stuff between 1980 and 1985 ... Just knowing where the idle adjustment screw is (thanks Ben) has gotten me in better shape - not stalling at traffic lights any more! Once I find the vac line, I will have everything else I need to know ready to go! No worries ... Thanks to the folks on the Forums, I have done more then I ever thought I would with regard to the mechanics of motor vehicles!

Read the Purple Section: http://web.mac.com/drewplatt/Gelandewagen/Welcome.html 

Drew, further investigation leads me to wonder if your G has the same 'air slide" (tubing/vac lines) as mine. I was re-reading Bram's post awhile back of which Hipine chimed in saying his 280 did not have some of the same setup as Bram's(1984) or mine (1985). It just dawned on me that yours, being a 1980, might not have the same apparatus of the photo I posted....sorry. Mine is all apart now, I am "re-learning" the system. I bet your G does not have the shlubventil by which the vac line I have the arrow pointing to is going from the upper air slide hose.

You may need to seek some help from someone with a G closer to your build year that has A/C and see how their idle adjustment is configured....or even if they have one for that matter. I am deeply sorry for any confusion. If you ever have to take your intake manifold off and find some questionable hoses that need replaced PM me as, some of the ones that I am replacing are actually in pretty good shape....and they are expensive.

Here is a photo of where that "thing" is...it is the shlubventil, and aids in increasing/decreasing idle pending conditions of vac changes introduced by another source like a electro vacuum switch actuated by a/c compressor.  It will decrease/stabilize idle when a 'constant" vacuum is acheived ( if I remember right) 

Mike

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Hey Mike:

No worries! I believe you are correct about the pre 1984s not having the  shlubventil. I have an email out to Ben, who sold me the truck to see if he has any suggestions. Non the less, there must be some vacuum hose to which I can connect. This morning it does not matter as I have to go get one of my AC hoses re crimped. My refrigerant was low and as I was refilling it, what might have been a slow leak, became a fast leak - lol ... Also, the list of little projects on Erlla (280GE) is sufficiently filled, that the idle control was not the last thing. I had to fix the DVD player and run a control line for the fresh/reticulating air flap system. In that system, I am still mystified as to why the motor is continuously energized when the is in both positions ... I posed that question/thought in another thread, but have not seen any response ... I read the other posts that I could find regarding the flap, but only say one other comment about the issue or having constant power to the motor.

The next thing on my list should be wiper seals, but I will have to read up on that project. I would guess mystery water in the floor pan can only mean it is time ...

As always, thank you for your help and kindness - whether I have the "thing" or not,  spending time in the engine is the oly way I will learn the mechanicing stuff ...

I am still a little bit confused that maybe I have things hooked up wrong.  Looking at the EPC, diagram shows electrovalve for a/c idle going to distributor and throttle plate.  How would this increase idle when activated ?

Mike 

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Mike:

Now that drawing looks like what I have - I don't even need to go out to the truck to say so ... I wondered if the line - I think it is clear and yellow or clear and brown stripped was the right one ... Should the fresh air for the module be tapped off the air intake system after the filter, before the intake manifold???

Also - which post is positive and which is to ground? I guess it makes a difference in the idle or does the spin of the motor in the module not make a difference? 

I don't think positive/negative makes a difference in the switch.  Right now I am hinestly uncertain as to the vacuum connections...research will be in order for me this week, as I clean,organize and make all like it is "suppose" to be.

More to follow as I learn more.

Mike

When Steve gets back from vacation at Eurotruck, I will ask him how his is hooked up, as he has a/c and the valve thing hooked up.

Mike

fernweh - 6/30/2008 11:40 PM

DesertStar - 6/30/2008 2:15 PM

I am still a little bit confused that maybe I have things hooked up wrong. Looking at the EPC, diagram shows electrovalve for a/c idle going to distributor and throttle plate. How would this increase idle when activated ?

Mike

IMO the vacuum line comes from the intake manifold goes to the electric solenoid and then to the ignition distributor. When you advance the ignition timing the idle rpm will increase. You can figure out if the vacuum pot on your distributor advances or retards the timing - if at normal running condition the timing is retarded the solenoid drops the vacuum (vents the line), ignition advances a bit and the idle rpm goes up a few - one of two scenarios Karl

Ok I see now, I did not even think about that.   Let me pick your brain a bit more.  My intake has two ports for vac connections as shown here. Is it common for one of them not to be in use ? Or more so, for other options/emissions that would require another port.  Currently my distributor is piped to one of the ports while the other is plugged.

Mike 

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Crap, I forgot about that, as I no longer have an EGR...things are starting to come together now.  Thanks Bram and Fernweh.

Mike 

fernweh - 7/1/2008 1:40 AM

DesertStar - 6/30/2008 2:15 PM

I am still a little bit confused that maybe I have things hooked up wrong. Looking at the EPC, diagram shows electrovalve for a/c idle going to distributor and throttle plate. How would this increase idle when activated ?

Mike

IMO the vacuum line comes from the intake manifold goes to the electric solenoid and then to the ignition distributor. When you advance the ignition timing the idle rpm will increase. You can figure out if the vacuum pot on your distributor advances or retards the timing - if at normal running condition the timing is retarded the solenoid drops the vacuum (vents the line), ignition advances a bit and the idle rpm goes up a few - one of two scenarios Karl

All this makes sense - should the air inlet on the module be filtered i.e. draw air from post filter intake air or does it not matter?