What is dieseling ?

A car is supposed to stop running if the driver switches off the ignition. There must be no more fuel coming in the chambers to be ignited by the spark plug. Unfortunately, in an internal combustion engine, things do not run as smoothly as it should. Dieseling is what you call a car that still runs even if the ignition is off.

Dieseling usually happens when other heat sources ignited the fuel, other that the spark plug. Dieseling could last a couple of minutes, depending on the fuel remaining in the chamber or until the source of heat cools down. Dieseling occurs in diesel-based engine cars, so if this happens to regular gasoline cars, there is a problem.

One cause of dieseling is with the use of low-grade oil and fuel. It happens when an engine burn the fuel and carbon deposits rapidly develop in the combustion chamber, causing the pistons to rub against metal and develop a hot spot. If the ignition is off, the spark plug can no longer ignite the fuel left in the combustion chamber, but the burning carbon can still set it off.

To prevent your cars from dieseling, it is best to keep your car appropriately supplied with coolant and oil. Because overheating develops hot spots that leads dieseling, it is important to have your valves and pistons checked for sharp edges that could overheat your cars. You can also use additives that remove or decrease carbon or use high-quality fuel to avoid future dieseling.