also the horn never worked when i was taking these reading

It's starting to sound like a problem with the vacuum portion of the ignition switch. I still don't understand how the horn is related.

Jeez, this is crazy.

I was thinking that pressure on the steering column was causing the vacuum valve to open somehow - but that can't be possible. The two are completely seperate, right? I mean the ignition assembly is mounted in the dash and the only things that hook to it are wires and vacuum. (This is from my 240D though). So if the horn is actually killing the engine, it must be that there is a short in a horn wire to an wire going to the ignition. Problem is, how does a rouge electrical current (or lack thereof) cause the vacuum valve to open - makes no sense. When you push the horn, can you hear anything coming from the ignition? Does the key move a little?

Is this for real? I think you will need to pull in the instrument cluster (easy enough) and take a look at the ignition assembly to see what is going on.

Have you pulled the fuse to the horn and tried the crazy engine kill method to verify that somehow something electrical is involved?

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

The wires that attach at the horn(s). Find the horn(s), usually in front of the radiator.

__________________
Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO

I know the problem and the solution. Your horn is hitting one of the vac solenoids for ac or the like and your vac is misrouted. Its the only solution that makes **** for sense.

Lets start with basic testings. Pull the kick panel, pull the two brown vac lines on the iginition (remember which one is which) and verify that one is providing vacuum at all times even with the engine off (start engine verify vac, hit kill switch on ip verify vac). Then on the other line a draw a vac and verify the engine shuts off.

I bet money that your vacuum source is not the directly from the brake line like it should be. The shutoff is completely mechanical/vac operated, it is IMPOSSIBLE for the horn to affect it unless there is a device between point a and b that is preventing it from getting a vac source.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Well, we now your vacuum level is too low. The vacuum should be around 21 inches at sea level. Check your vacuum level with the engine running at a connection as soon after it branches off the main line as possible. Report back with the reading. If your whole system only has 7 inches of vacuum, there's a problem such as a leak or a bad vacuum pump. If you're reading 21 on the whole system but only 2-7inches when the shut off valve is activated by the ignition, then there's something wrong in the ignitino portion of the circuit.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

will run more test tommorow Kerry i have to go out of town til tommrow afternoon and i believe my friend who knows alot more will be back tommorow all this info is a huge help , winmutt the two brown wires tot he ignition i saw look red to me were you refering to these in this upside down picture

Attached Thumbnails

 

was able to test the main line is does have a reading of 21 but it does also lose it soon as the car is shut off

So there is a vacuum leak between the main line and the ignition or shut off circuit.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Any update on this mystery? I'm dying to find out what the deal is!

__________________
1984 300TD 1981 240D

i was about to let people know that i should have some progress early next week i switched over to fizing the blinkers becuase this horn thing got to heavy for me,,my mechanic friend will be back monday so this thing so be solved early next week, but i will for sure keep everyone of you kind souls updated on what the heck happens

Since it appears to be self-correcting for a few applications ('works like 5 times normally') it sounds like it's pulling vacuum from the reservoir in order to shut down.

Some things don't make sense, like where is the unconnected or capped line that should be where the drill bit currently is?

I'd look at this thread and try to get the lines correct and eliminate things like the drill bit repair. I still don't understand how the horn fits into it, though.

1985 300D vacuum crazyness.

This is a great thread , I wish I were there as it's prolly dead simple .

The last photo in your first group clearly shows mis conncted vacuum pipes . the lowest one is a tiny black one , it looks like the vent pipe that won't hold vacuum if you suck on it , if so , disconnect it and plug that leg of the 'T' connector .

The plastic pipes you see as red , are indeed the brown engine shutoff pipes ,
one has a blue stripe on it .

Not knowing how Mechanical you are makes me hesitant to give the basic trouble shooting procedure necessary to sort this out in 20 minutes or so .

I'd hate for you to re-arrange the vacuum connections then have it worse .

As you appear to have a vacuum gage , at the very least you should test the primary vacuum pipe from engine to brake booseter with the other vacuum pipes disconnected and capped off~ if it doesn't raise up 21" + of vacuum within a few moments of starting the engine , your vacuum pump needs repair , prolly just the check valve as you cannot have anything vacuum operated work correctly until it easily and consistantly makes 21" of vacuum .

One easy leak test tool is a bit of rubber hose , slip one end on the device in question and the other end in your mouth and suck on it ~ as soon as you feel it holding vacuum , place your tounge on the hose , it must hold vacuum indefiinately ~ test the round vacuum shutoff valve on the back of the IP as they wear out and get slow leaks , ditto the ignition switch's vacuum valve , if it leaks , it's bad and must needs replaced before you touch anything else .

I hope this helps , remember : K.I.S.S. and don't go yanking out the dash binnacle mindlessly , test each seperate thing first as these are simple cars .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Oh yeah ~ don't worry about that , it's the port for the now disconnected EGR valve , I'd make it a cleaner & lighter plug but no worries .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

thanks nate and all. yeah i am hoping my buddy will be here tommorow i am new to learning all this mechanical stuff but i have already learned a ton from all the super intelligent people on this board,i am leaving it alone til he gets back i am working on some minor stuff like replacing hazed switch.. becuase my blinkers wouldnt work, will hopefully have some good news tommorow im ready get this baby on da road