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I am having a bit (A lot) of difficaulty turning off my 79 300 td. The ignition will not respond. I cant find the shut down lever. And disconnecting the battery does nothing. Any advice would be greatly appreciated.
 

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240D
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19 Posts
i think i read the system is vacuume opperated...could be a problem to troubleshoot ther...

i think i read the ignition system is vacuume opperated...could be a problem to troubleshoot there. there may be some more knowledgable people here about the common vacuume probs in the w123....
 

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2021 SL770
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I am having a bit (A lot) of difficaulty turning off my 79 300 td. The ignition will not respond. I cant find the shut down lever. And disconnecting the battery does nothing. Any advice would be greatly appreciated.
You probably need a new shut-off valve -- it's a common enough problem. The part is inexpensive and attaches to the back of your injection pump.

Ron
http://germanstar.net
 

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1987 300D Turbo
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189 Posts
I have a similar issue with my 83 300D. We've tried several used shutoff valves and they a...

I have a similar issue with my 83 300D. We've tried several used shutoff valves and they all seem to not work... what else can it be? I'm already assuming its the vacuum pump since the door locks are also screwey (weird acting). The brake booster works just fine though.
 

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84 300D Euro
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44 Posts
Check the door servos.

I was having the same shutoff problem. MB mechanic said the same the shutoff valve was bad. What the problem turned out to be was the rubber coupling in the door lock servo. Went to a local pick and pull (before I knew what I was looking for) and grabbed the 3 servos, passenger front , and both rears. 2 were also bad. 20 years has its effect. If you look at the mechanism, the rubber cracks, causing a vacuum leak. A proper one fixed my problem. Maybe yours too. Any vac leak will have an effect in shutoff. Its just a weird place to look when your having issues under the hood.

Hope this helps...
 

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1991 300E
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117 Posts
I know this sounds strange but I have heard more than one instance where it works and I li...

I know this sounds strange but I have heard more than one instance where it works and I lived with it for a while; Get out when you're parked and the car is still running and lock the doors and the engine might shut off. Simple as that. I lived that way for two months once when I was broke and saving up for parts. The engine shut off every time for me. Or you should be able to raise the hood and push the manual shut off lever. It should be one inch square piece of metal on the drivers side of the valve cover in amongst the linkage and it should say STOP in big red letters. But you definitly have a vacume prob, just to cast my vote. Good Luck and if you have any more ?'s as you are narrowing it down, ask 'em. One of us is bound to know an answer to some of them based simply on probability!
-M-
 

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2021 SL770
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Re: I have a similar issue with my 83 300D. We've tried several used shutoff valves and they a

I have a similar issue with my 83 300D. We've tried several used shutoff valves and they all seem to not work... what else can it be? I'm already assuming its the vacuum pump since the door locks are also screwey (weird acting). The brake booster works just fine though.
It's probably not the pump, or your brakes would be suffering. It's more likely a vacuum leak somewhere else in the system, which can be really tedious to locate...

Ron
http://germanstar.net
 

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1987 300D Turbo
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189 Posts
Problem found

Well.. I finally got time to play around at the pick-a-part and got 2 of those. Looking at our W123, I found out one is slightly cracked but the problem isn't there. The problem with ours is the master vacuum switch in the driver door. If you are having troubles with your car and checked the Door lock servo, try the master vacuum switch also.
 

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2005 MB S430 4Matic
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112 Posts
Hehe. My uncle used to do the trick with locking the doors all the time on his w123 300T...

Hehe. My uncle used to do the trick with locking the doors all the time on his w123 300TD wagon. Worked all the time. Funny that you mentioned that cause I was going to post the same solution. Thank god nothings wrong like that on my 240d.
 

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'83 300SD Turbo
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77 Posts
The first week I owned mine I broke the vacuuum line that comes off the check valve in the...

The first week I owned mine I broke the vacuuum line that comes off the check valve in the hose running from the pump to the brake booster. Turns out, that's the line to the ignition switch. I couldn't shut the car down so I had to rig it and order a new line when I got to work Monday...
 

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s500- 300td
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92 Posts
easy fix

I have a solution that will not cost anything and I one of my 82 300td came with. A wire that was tied the turn off levery under the hood and went through the ac vent, for easy shut off, I worked great for years.
[:)]
 

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85 300cd, 2000 ford excursion diesel, 1999 528 itwagon 95 roadking
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371 Posts
the vaccum controller on the injector is a major way for the car to shut off, take a vaccum pump and w/ engine running, connect the vaccum pump to the fitting on the injector pump and pump up vaccum the cat should shut off, chech thevaccum hoses attached to it. if that is ok the back of the starter switch lower has a vaccum controller also and will not shut off the car if its broken check it the same way it should hold vaccum. connect the vaccum pump to the lower part of the switc`h it should hold vaccum. next connect the pump to the vaccum line that connects to the switch also should hold vaccum if not, the vaccum line is cracked. good luck also if yopu push the throttle linkage to the valve cover and hold it it will starve out. usually they have a red tag about a inch theat reads stop on the linkage.
 

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'72 220d, 250td, e320cdi
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249 Posts
i have a question about manual shut-off... (i have not done it yet) when u press the lever i gather it cuts off the fuel then the engine stops... once the engine has stopped does it all go back to normal again.. so when u want to start it again it will have fuel and will start right up? stupid question to you guys i guess!!
 

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1983 300D
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78 Posts
[:(] NO! I don't think so. On all the other diesels I've owned (big trucks and pickups) the manual shut off releases compression on the engine and it shuts down. As a matter of fact you don't need power to run a diesel, just fuel, air, and compression. Since it is NOT a good idea to starve a diesel for fuel (and it could let air into the system) I wouldn't think MB would do it that way. It wasn't all that many years ago that big trucks all had a lever in the cab to release compression to shut them down.
Anyway, once you release the lever it is ready to start again.
 

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'72 220d, 250td, e320cdi
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249 Posts
im glad i showed everyone how clever i really am! [:I]
 

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85 300cd, 2000 ford excursion diesel, 1999 528 itwagon 95 roadking
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371 Posts
yes you can restart the engine when you shut off the engine w/ the emergency stop , all It does is starve out the engine of fuel.when the car is running can you hear any hissing?
 

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85 300cd, 2000 ford excursion diesel, 1999 528 itwagon 95 roadking
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371 Posts
a different way to tell is a bit weird but stick with me. you need some one who is a smoker, no not crack or grass just cigs or cigar, disconnect the vac line on the ign switch andtaks a deep drag on the cig and exhale blowing the smoke into the vacc. line you should see if there is a crack in a line or bad servo and the smoke will idenify whitch door or line is broken, check doors trunk, under dash and under hood. cigar works best with me.its best if two people do this .reconnect the line and go under the hood and remove the vacc line that shut off the car and give the same test.yes its strange but it works. good luck
 
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