I have read some of the treads about this issue and I am beginning to narrow down the problems. My door locks do work and other vacuum applications work to the best of my knowledge. It looks like it might be the shut-off valve. I observed the engine being shut off and the lever only goes down about 75% of the way and the engine sounds like it is running at 50%.

Any suggestions

Check the vacuum hoses going to the shut off switch (in the dash) and from the switch to the valve. The rubber connectors can dry out and leak. What you can do is connect a Mitivac to the valve and see if you can manually shut down the engine by pumping the valve.

If you can shut off the engine with the Mitivac the problem is in the lines or the shut off switch.

Otherwise it is not hard to replace the shut off valve on the IP. Just be careful to engage the valve to the IP linkage properly or you could end up with no way to shut off the engine I have not heard of anybody doing it, but it COULD happen...

Good Luck

__________________
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If you don't have a mity vac, put a piece of vacuum hose on the shut off valve and suck on it. If it's good, two or three strong sucks should shut off your engine. Be careful, if the diaphragm has a hole, you could suck oil. If you can't suck it off, chances are the shut off valve is bad.

__________________
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

thanks for the info. I will work on this later today. I do not have a minivac so will try the vacuum hose approach. I hope I don't have to to into the dash.

Check for oil in that hard line.
I was able to pull vac with a mity-vac, the engine shut down.
There was enough oil in the line to leak and stain the kick panel just below the ignition switch.
A new shut off actuator/valve under hood fixed the problem.

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83 SD

84 CD

Ummm, I really don't know what to say about this posting. The possibilities are just too tempting!

+1

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1993 W124 300D
-297K on the clock as I type this.

I do not have a mitivac so I used my natural vac system and tried to suck on the line from the shutoff and the lever would not budge a bit. RPM went down to almost nothing but would not shut off. There was no oil in the line and I cannot find any under the ignition. My thoughts are that he shutoff is bad and I will need to replace it. Does this sound correct? Next question, where is the best place to go for a new/used/rebuilt shutoff and is a used or rebuilt an viable option?

I'd go new. Click on buy parts on top of this page.

__________________
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

I don't think there is a rebuild kit, so as kerry suggests, click on the buy parts tab above.
If the lever doesn't move, you've got another problem too, check the linkages carefully.

__________________
83 SD

84 CD

Hello, I've had an '85 300TD since I was 15 years old. Never had a problem until now. When I turn the key and take it out, the engine acts as if there was a key still in it. Like all these other people, I have to open the hood and hit the kill switch on top of the engine.

I am really interested in restoring this car and.. well.. I guess that starts with this. I've checked the actuator under the hood and the IP shutoff several times, thinking I missed the leak. Just today, I decided to actually get in the dash and check the shut off switch there. As soon as I got the kick plate off and looked up, I saw the switch with 2 little droplets of oil on the underside. I also noticed that the rubber grommets used to connect the hoses were old and shotty and also had oil on the outside of them. I didnt even bother sucking to shut off the engine. I'm just assuming that this switch has gone bad.

Am I right?

^^I'll suggest the afore mentioned actuator located below the VacuumControValve, follow the brown hard vac line.

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83 SD

84 CD

Gah! Someone replaced all the lines on my VCV and didn't re-color-code them.. >.< Sigh.. Back to trial and error I suppose.

The line I'm referring to is not part of the VCV, but good luck.

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83 SD

84 CD