Plugged spray holes in a diesel engine fuel injector will cause excessive smoking at idling speed, in addition to what?

Plugged spray holes in a diesel engine fuel injector disrupt the proper atomization and distribution of fuel. This can lead to uneven fuel delivery, resulting in incomplete combustion. While idling, the injector may struggle to deliver the necessary fuel flow, causing excessive smoking. However, the real concern arises when the engine is under load; this situation exacerbates the incomplete combustion that results from the blocked injectors. Under load, the demand for fuel increases, and if the spray holes are plugged, the injector cannot supply the necessary amount of fuel in the correct manner, thus leading to even more noticeable excessive smoking.

The impact on smoke levels when the engine is under load indicates a significant failure in the fuel metering and combustion process, which highlights the importance of maintaining proper fuel injector function for optimal engine performance.