Engine shut off

[zenspector]

My '82 300TD will not shut off when the ignition is switched off. It started doing this sporadically, but has since begun to not shut off more and more. The service manual shows a vacuum fuel shut off diaphram, but I can't figure how it is activated. Any help would be appreciated.

[blindwolf]

It is activated by a switch on your ignition switch. There are two vacuum lines on the switch. One is vacuum supply from the pump, the other when engaged sends vacuum to the shut off valve, actuating it to shut of the engine.

[300SDog]

Couple of diagnostic tips before you attack the valve:

Try shuttin the engine off *after* central locking the doors with you still in the car. If shutoff works with doors locked then the problem aint the valve.

Try disconnecting and golf tee plugging vacuum feed to the horrible ACC system at the firewall driver's side. Again if the car shutdown comes back to life then yer problem aint the valve.

Finally inspect and jam tight all rubber elbows and joints throughout the vacuum system including the EGR and triple tree on top of the valve cover before condemning the valve.

[sdpartz]

I have the same problem with my 82 300D turbo which I bought a couple of days back, Swapped the vacuum valve & checked the vacuum lines so far the problem still persist, central locks don't work at all,will check the horrible a/c vacuum lines next.


97 C230 OZ Racing wheels, Sport pkg interior
94 C280 Brabus Monoblock 6, Bose Pkg (For sale)
82 300D Turbo ( my first W123 & 4th Dsl)

[Toblin]

Check the vacuum connections in and around the oil filter casing. They often get broken while removing the cover. You'll need to look close because it could be just a hairline crack.

[kerry]

Simple test of the shut off valve is to replace the brown vacuum line going to it at the back of the IP between the IP and oil filter housing with a section of vacuum hose. Suck on the hose with the engine running. If the diaphragm is good, you should be able to shut it down with a couple of sucks. If it is torn, be prepared to quit sucking when the oil hits your lips.

[bobodaclown]

Originally Posted by kerry

Simple test of the shut off valve is to replace the brown vacuum line going to it at the back of the IP between the IP and oil filter housing with a section of vacuum hose. Suck on the hose with the engine running. If the diaphragm is good, you should be able to shut it down with a couple of sucks. If it is torn, be prepared to quit sucking when the oil hits your lips.

If possible use a syringe. You won't have to suck.

[jbach36]

Beware of a runaway diesel engine after you repair it. Be prepared to starve the engine of any air if it becomes a runaway (just red lines on the rpm and blows up and can kill you). Email me if this is not clear.

jeff

[Bob Albrecht]

Your exact symptoms happened to me. There is a vacuum line that connects to the injection pump, but you know that.

On my car I accidentally loosened the line while replacing the fuel line. It was just touching the connection on the pump and sometimes it would suck on the connector and stop the engine, and sometimes it wouldn't. I finally figured it out and just pushed the vacuum line back on and it hasn't happened since. I hope it is that simple for you.