Diesel engines do not rely on spark plugs for ignition, unlike gasoline engines. Instead, they use compression ignition, where the high pressure and temperature created in the cylinder during the compression stroke causes the diesel fuel to spontaneously ignite. As a result, diesel engines can potentially run even without any spark plugs, although they may start and run rough.
However, spark plugs play an important role in starting a diesel engine by pre-heating the combustion chamber and assisting with the ignition process. When a diesel engine is cold, it can be difficult to start due to the low ambient temperatures and the need to reach a high compression ratio for ignition. The spark plugs provide a heat source that helps to raise the temperature in the cylinder, making it easier for the fuel to ignite.
With only one spark plug functioning, the engine may experience difficulty starting, especially in cold conditions. The pre-heating effect of the non-working spark plug will be missing, resulting in longer cranking times and potentially increased wear on the starter motor.
Additionally, the engine's performance will be compromised with one non-working spark plug. The combustion process may be less efficient, leading to reduced power and fuel economy. The engine may also run rough and produce excessive vibrations due to the uneven combustion.
Therefore, while a diesel engine can potentially start and run with one non-working spark plug, it is recommended to replace the faulty spark plug as soon as possible to ensure optimal performance, efficiency, and durability of the engine.
