Egon, That would not have made my day. I guess we all should have a contingency plan for what to do if you can't make it stop. I was not having fun when the steering wheel mounted switch and or the brakes would not turn off or disengage respectively the cruise which was in the process of trying to get me to set a new land speed record on a busy/crowded freeway in San Diego traffic. Had the key not killed it I would have been in a lot of trouble because the brakes will not stop the truck with the throtle at max with the Cummins Turgo diesel.
The next step would hurt me but would have been neccessary... shift to neutral, and hope for the best!
My wife's MB 5 cyl turbo diesel had a clearly marked (red label) lever under the hood labeled "Stop Engine" or some such, in English no less to cover the case when the key actuated stopper wouldn't.
I have read and heard discussed a scarry diesel situation that I luckily have not experienced personally. With a badly worn engine you can get enough blow by of crankcase fumes to provide the engine with enough fuel that it won't stop even with the fuel shut off. Covering/plugging the air intake deprives the engine of air and it dies.
If you have a manual trans you can let the clutch out at idle to kill the engine but with an automatic it would require you to stop the intake air. So, Egon, what was your situation?
Patrick