Runaway Cummins Diesel Displays Autonomy, Restarting After Being Shut Down

      Georgia Motorsports Media

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      While many consumers are concerned about connected cars handling their personal data and self-driving capabilities, it's worth noting that diesel trucks can exhibit their own alarming behaviors. A Cummins-powered sled puller recently experienced a runaway engine incident that culminated in a large fireball before it was finally shut down. Additionally, when safety crews arrived, the truck’s starter began to spin uncontrollably again, triggering a second runaway situation.

      This incident occurred during the Aonia Truck and Tractor Pull in White Plains, Georgia, on May 17. The Southern Pullers Association shared clips of the event online, and the video indicates that something was amiss right from the start. The second-generation Ram emitted a steady puff of white smoke as it took off, and soon after, flames began to glow behind the truck’s grille. Within half a minute, the truck's engine was engulfed in flames.

      Runaway engine incidents happen when an excessive amount of fuel is unintentionally introduced into the cylinders, which could be diesel or another flammable substance like oil. Such malfunctions can arise from several issues, such as a stuck injection pump supplying too much fuel, a faulty valvetrain, or a turbo seal leaking oil into the combustion chambers. While the precise cause in this case is uncertain, the initial white smoke suggests it may have been related to oil.

      However, even more puzzling was how the starter began spinning again around the 1:23 mark. The engine had been off for more than 10 seconds before it spontaneously restarted. Track safety personnel were present with fire extinguishers and a hose when the truck astonishingly started itself once more, creating evident alarm.

      The sled operator had already disconnected the truck and moved away, meaning there was no added weight to prevent it from potentially shifting into gear.

      “It’s my understanding that the sled operator tried to activate the kill switch, but the mechanism didn’t engage the guillotine,” said Keith Haag, the Georgia Motorsports Media videographer who captured the incident. “In the meantime, the driver was attempting to unbuckle and escape safely—understandably, opening the hood was not his primary concern. By the time someone tried to access the hood, it wouldn’t open,” Haag explained.

      “After the driver got out, the kill switch at the back of the truck was manually activated, but at that point, the fire had already distorted the guillotine, preventing it from closing completely and stopping the engine. There was also a front-mounted battery kill switch, but the flames rendered it inaccessible. This allowed the starter to re-engage, resulting in the engine running away again,” Haag noted.

      Despite the alarming situation, the engine’s RPMs would spike and then drop, creating the illusion that the runaway was somehow controlled, even when it wasn’t. Each increase in revs intensified the fire, and the potential dangers associated with that are well-known. It’s remarkable that the truck didn’t explode, and Haag pointed out that both the truck and engine are salvageable.

      Such scenarios are unpredictable, and safety teams must be properly trained to handle runaway engine situations when they arise. Most teams are prepared, as these types of incidents do occur occasionally at events. It is crucial to understand that even if it seems that chaos is temporarily contained, things can worsen rapidly. Anytime flammable liquids are combined with a source of combustion, whether from a spark or compression, it can result in a hazardous situation.

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