What are the causes of unstable diesel engine speed?

2 Answers
McCassandra
07/28/25 8:53pm
Diesel engine speed instability may be caused by governor failure, fuel system malfunction, fuel injection pump failure, etc. The operating condition of a diesel engine affects vehicle driving. Below is a detailed introduction about vehicle driving: 1. Overview: Driving a vehicle is one of the essential skills that modern individuals need to master. To acquire vehicle driving (driving-a-motor-vehicle) skills, one must meet the required age and physical conditions, and undergo training and examinations on road traffic safety laws and regulations, relevant automotive mechanical knowledge, and safe driving practices. 2. Others: The permission to drive a vehicle is granted through the issuance of a driver's license. This indicates that obtaining a driver's license is a formal procedure that must be issued by an authorized agency.
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SimonLee
08/12/25 1:36am
As someone who frequently repairs old diesel vehicles, I find that unstable RPM is a quite common issue, primarily rooted in the fuel system and mechanical wear. To be specific, fuel line problems are the prime suspects—such as clogged injectors causing intermittent fuel supply, or internal wear in the injection pump leading to fluctuating fuel pressure, which directly chokes the engine. Air supply is another issue; a dirty air filter restricting airflow or cracks in the intake pipe causing leaks can disrupt the air-fuel mixture balance. Additionally, issues in the electronic control system, like aging RPM sensors or poor ECU circuit connections, might send incorrect signals. Even poor-quality fuel with impurities can accelerate such failures. I once repaired a truck with a cracked fuel line, causing the RPM to fluctuate wildly—it took hours of checking all connection points to fix it. In short, these problems should be caught early; otherwise, they can lead to increased fuel consumption at best, or black smoke and engine damage at worst. I recommend paying attention to unusual engine sounds and vibrations, and regularly cleaning filters and using good-quality diesel.
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