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Discussion Starter #1
I have a 1980 300D. Yesterday it decided that it wouldn't shut off with the key. I checked the vacuum line to the injector pump and it's making vacuum when the key is shut off (but not when key is on). Any thoughts?
 

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The same thing has happened to my '85. Are your power doors not working either? I didnt have time to examine it at the time, so I payed my local German auto mechanic to fix it, which didn't cost very much. I think is some kind of vacuum valve. I have never tried it, but I heard from a friend that shutting the car off in drive will make it turn of (and then you can put it in park), and I also think that this should work. Good luck
 

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Discussion Starter #3
yeah, my locks won't work either--although they haven't since I acquired the car, and the engine thing just began yesterday. I'll try shutting it off in drive and see if that works. thanks.
 

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wolivo:

1. There is a shut off lever on the injection pump. Use that for stopping the engine until;

2. you find the vacuum leak. Look for a loose vacuum line under your hood. If it is no obvious, you may need to get someone with some vacuum diagnoostic equipment to chase it down.

-Scott
 

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My 84 300 SD I recently bought also will not shut off with key. Don't know about the locks as I haven't tried them yet. I found the way the previous owner had been shutting it off last night while looking under the dash. They had a rubber vacuum line hanging under the dash, connected to one of the plastic lines(the one closest to the column,brown/yellow stripe) going to the switch. This is the line that leads back to the injection pump shutoff. Just suck on the line a little and it will kill the engine.
Not as nice as just turning off the key, but at least it works without lifting the hood!

Now a question? Is this caused by the shutoff switch on the valve cover being bad?Or caused by a vacuum leak?
 

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Typically this problem is caused by a vacuum solenoid that is integrated into the top of the injection pump. It actually actuates the previously mentioned stop lever. It is very easy to replace. I just did mine a couple of weeks ago, and it took all of about 20 minutes to do.

HTH,

Neil
 

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Neil:

Thanks for looking that up. I may try one of those on the SDL. She does not want to shut off if I run her for short distances. I guess I could switch the one on the SD for the one on the SDL to see if that is the part.

-Scott
 

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Discussion Starter #9
an update...

While trying to fix the "no shut off" problem I managed to make the locks work (vacuum lines on one passenger door were disconnected). I tested the shut of solenoid at the pump by running a vacuum line directly from the main line (going to the brake booster) to the pump. Still wouldn't shut off. I removed the shut off solenoid from the pump. When I sucked on it, it didn't seem to pull the lever in all the way. I deduced that it was junk. I went to my dealer, who said at least 5 days to order the part. I put the old one back in so I can continue to drive the car. My wife just took the car out and when she came back the car shut off for her. Maybe it just doesn't like me.
 

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You actually sucked on it? Gross! Get a mityvac! :lol:

That often happens when the solenoid is on the way out. Sometimes works, sometimes doesn't.

Glad to hear the locks are fixed.

-Neil
 

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My 1986 300 SDL was running after switching it off and I tried the "turn it off in Drive technique" and it worked. I had been getting out of the car and manually pressing the "stop" switch. I like turning it off from inside the car better. Thanks for the tip. I will be replacing the shut-off valve this weekend.
 
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