No spark required on a diesel engine, the high compression generates so much heat that when the fuel is injected it self ignites..
That's it why you cant stop a runaway diesel by switching it off.. You have got to either stall the engine somehow, cut off the fuel supply, or block the air intake.. And standing over an engine that is red-lining whilst you remove the air filter so you can block the air intake takes a massive amount of courage.... or stupidity...
lmho...
In this instance i think the turbo seals have gone allowing oil to leak through to the air flow side, thus feeding the engine... But that is just a guess really....
...