Why Diesel Engine Runaway?

Diesel engine runaway occurs when a diesel engine ingests a hydrocarbon vapor, or flammable vapor, through the air intake system and uses it as an external fuel source. ... If not stopped immediately, it can cause the engine to overspeed, the valves to bounce, and flames can pass through the manifold.

How do you stop a diesel runaway?

In order to stop a runaway diesel engine, you must either cut off the air supply or the fuel supply. Since it's drawing fuel from some unknown source, the easier option is to cut off the air supply. Finding something to block off the intake can slow down the RPM and stop the engine from running.

How common is diesel runaway?

A runaway diesel used to be a relatively common occurrence. But now as times have changed, it's a rare situation in modern diesels. Most Electronic Control Modules (ECMs) can meter the fuel more accurately and sensors warn the ECM and allow it to prevent things like this from happening.