Diesel runaway: If you cannot be bothered to rebuild the engine to get rid of the blow-back, try fitting a cholostomy bag (disconnect the breather from the air cleaner and instead feed the breather pipe into an empty oil container). I have had diesel runaway with a Land Rover 200 TDI diesel (it was terrifying but I stopped it by banging it into gear and releasing the clutch). This runaway was caused by a leaking diesel pump (the leaking diesel was leaking into the sump and caused the oil levels to rise). I also have a naturally apsirated diesel Land Rover which is suffering runaway. The breather pipe feeds straight into the air cleaner. The sump is not overfilled with oil, the piston rings are new and the sleeves are within tolerances - so what else other than overfilling and worn rings can cause runaway?

In turbo diesel engines the most common reason for a engine to run away is because the oil seal has been sucked out. Turbo starts to leak oil, the more oil that is drawn into the cylinder the faster it runs, faster it runs the more oil it sucks out. Turning the engine on/off switch off does no good because by this point the engine is running on engine oil not fuel. To kill it you block off the intake air flow. I have seen Cummins 855's, M11's, N14's, ISX's -- Cat 3406's, C12's, C15's, 3408's, International 466's, 530's, 7.3L's and the list goes on. I have seen heads blown off, pistons out the side of the block, you name it it can blow off at 6,000 RPM+.

Probably the best set up I ever saw was what Detroit did on their 8V92's in fire truck applications. The engines have a turbo and a super charger. In the super charger assembly there is a shutter assembly. When the key is turned off the shutter closes and will kill even a run away engine. It needs two things to run, air and fuel, take any one away and it will shut off.