Originally Posted by James L

I have done numerous searches and reads on this wonderfull forum on the famed diesel engine shut off woes. My 1984 300SD is/was not shuting down when I removed the key. I have the a new vacuum shut off valve but do not want to install it until I am sure that is the cause.

Automatic door locks work, heat works.

Pulled a mity vac directly to the shut off valve next to the IP and it shuts the engine off.

I have cleaned vacuum conectors, tee pee conector, vacuum lines looking for leaks. Not much improvement. Pulled instrument cluster and the ignition key shut off valve and vacuum lines have black oil on it-semi cleaned. Not much improvement.

Tightened the nuts on the big lines with a 19mm wrench going from the IP and now the engine shuts off, but not perfect.

Questions-Do i need to remove/complete clean or replace the ignition key shut off valve? Do I need to replace the vacuum shut off valve next to the IP? Where is this black oil on the key shut off valve comming from? brake booster? worn diaphram in the vacuum shut off valve? There is no oil in the line comming from the shut off valve to the control valve.

Thanks for the help