Mercedes 190D 1987 - dieseling / can't turn engine off

I've searched the forum and seen a similar issue for a 300D so i assume i have a vacuum leak of some type (or is the 190 different?).
The engine now runs on unless switched off manually by the lever under the inlet
manufold -
I had about two days when it only dieselled for a few second but now it's permanent ... and the red battery light come on too).
The door locks / brakes etc all seem to be working fine.... just the fuel shut off.... does this mean the fault is close to the fuel shut off?
Does anyone have a diagnostic rountine for this (i don't have a vacuum guage)?
I can see two vacuum hose .. one entering the back and one entering the top... which one of these is the engine shut off?
One thing ... I had one of the rear doors jam open (those annoying door stays.. and had to 'force' it shut ... that was about the time this stated ... is it possible that's caused the vacuum leak or is the stay a long way from the vacuum line??
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I'd say that forcing the door shut broke its vacuum line and caused a leak. Check that door's vacuum line and plug it if it's broken or cracked.
You should also know that the vacuum bellows inside the injection pump wears out and fails to pull the fuel rack to its OFF position. The bellows is called the "Shut Down Device" and should be installed by an experienced M-B mechanic.
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The back door will be my first port of call.
I've noticed that the manual shut off lever does move when the ignition is turned off.. just not quite far enough to cut the engine. Only a touch on the manual shut-off is required.
When you say 'this should be done by an experienced mechanic' - I understand that there a little difficulty in engaging the L-lever into the body of the the fuel pump when the shut down device is replaced... is that the issue? Looks pretty awkward to work underneath the air-inlet manifold as well, or would that usually be removed?
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Yes, hooking the device to the fuel rack is the knack that's needed.
Your further description suggests that repairing the door's vacuum leak will cure the engine shut down problem.
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I checked the door etc ... everything looked fine from what i could see which wasn't much. So i disconnected the vacuum line by the front passenger seat and capped it off. Still didn't turn off. So the back door doesn't seem to the the source of the problem. There no oil or anything in the lines.. they look clean. If i could trace all the lines I'd be tempted to isolate all the central locking and see it the shut off would work... but problem is I have a workshop manual but it's for the petrol version... diesel version don't seem available here (I'm in the UK). I'm a bit confused by all the vacuum lines. Is the shut off valve the one I think ...directly above the mechanical lever on the left of the assembly(it has two lines going into it with strange green plastic cylinder - looks a bit like an in-line filter). OR is it the one with a single line at the back hard up against the firewall. OR the single line on the top? Also I live in the country and getting to a garage is tricky.... not to mention extortionate!!!
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I don't know which vacuum line connects to the shut down device.
However, I've read that a vacuum filter was (and can be) installed on the line to the shut down, specifically to prevent oil from being sucked into the vacuum lines in the event the shut down failed.
So, with this clue I'd look at the line with the plastic filter.
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Had much the same problem with a 84 300 TD. Found that I could get it to shut off by locking the door (from the outside). It would run for about a minute, then shut down. Almost an automatic turbo spin-down interval.
Was also told that there is a double vacuum manifold along the steering column that is closed when you turn off the key in the ignition. Costs about USD 300 for the part, and at least that to have it installed.
Easier just to lock the doors.
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