Shish-ketruck on 93

A runaway diesel is one where the shaft seals in the turbocharger have failed, and the engine is sucking its own lubricating oil into the intake and burning it as fuel. Since there's no way to cut off the supply of engine oil, the engine will keep going until it self-destructs. There are some ways to stop a runaway; very few of them don't lead to drastic engine damage.