What causes engine torching?

Engine torching is primarily caused by excess fuel in the tailpipe. When there is an abundance of unburned fuel that accumulates at the rear end of the engine or in the exhaust system, it can ignite spontaneously or from a spark, leading to a visible flame or torching effect. This typically occurs when the fuel-air mixture in the combustion chamber is too rich, meaning there is more fuel than air for proper combustion, or due to issues such as fuel injector malfunctions that cause fuel to leak.

Understanding this mechanism is crucial for diagnosing engine performance problems and implementing corrective measures to prevent torching incidents, which can be dangerous and damaging.