Runaway Cummins Diesel Has Mind of Its Own, Fires Up Again After Shutdown

The Drive

3 days ago

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Some consumers are scared by what connected cars can do with all personal information and self-driving features, but diesel trucks can have a mind their own, too. While this Cummins-powered sled puller won't be driving itself to the repo lot anytime soon, it suffered a runaway engine event that resulted in a big ball of flames before shutting down. That wasn't all, though, as the truck's starter began spinning spontaneously once safety crews arrived on the scene, causing the engine to run away a second time.
The event took place at the Aonia Truck and Tractor Pull in White Plains, Georgia, on May 17. The Southern Pullers Association posted footage of the chaos online, and video footage reveals something isn't right from the start. The second-gen Ram leaves the line with a steady puff of white smoke, and pipes start glowing behind the truck's grille soon after. Within 30 seconds, the truck's engine goes up in flames.
Runaway engine events occur when an uncontrolled amount of fuel is dumped into the cylinders. That could be diesel fuel, or it could be another combustible source like oil. This can happen in a few different ways, from a stuck injection pump forcing too much diesel into the engine to a faulty valvetrain or turbo seal leaking oil into the combustion chambers. It's unclear what was the cause here, but given the white smoke at the start of the run, it could have been oil-related.
No matter the cause of the initial runaway, more baffling is how the starter began spinning again around the 1:23 mark. The engine had been shut down for than 10 seconds before it fired back up—literally. Track safety workers were on the scene with fire extinguishers and a water hose when the truck successfully started itself a second time, which was an obvious cause for concern.
The sled operator had already disconnected from the truck and reversed away, meaning there was no extra weight to hold the truck back if it somehow bumped into gear.
'It's my understanding that the sled operator attempted to pull the kill switch, but the mechanism did not engage the guillotine,' wrote Georgia Motorsports Media videographer Keith Haag, who was behind the camera during the incident. 'Meanwhile, the driver was struggling to unbuckle and exit safely—understandably, opening the hood was not the top priority at that moment. And by the time someone tried popping the hood, it would not open,' Haag said.
'Once the driver exited, the kill switch at the back of the truck was manually activated, but by then, the fire had already warped the guillotine, preventing it from closing completely and failing to choke off the engine. There was also a front-mounted battery kill switch, but the fire made it completely unreachable. That's what allowed the starter to re-engage and the engine to run away a second time,' Haag said.
Even then, the engine's revs would climb sky-high and drop back down, making it seem like the runaway was under control when it really wasn't. With every rev increase, the fire would grow, and we've seen what can happen as a result of that. It's a wonder the truck didn't throw any shrapnel, and Haag notes that the truck and engine are salvageable.
Situations like this are unpredictable, and safety crews need to be trained on what to do if and when they encounter a runaway engine. Most are, as this type of issue happens from time to time at these events. It's important to note is that just because chaos seems to be under control for a moment doesn't mean it can't get even worse in a hurry. Anything that mixes flammable liquids with a combustion source, whether it be spark or compression, can lead to a bad time.
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