What Causes Diesel Engine Runaway in Vehicles?
1 Answers
Diesel engine runaway in vehicles can be caused by the following reasons: Excessive Fuel Supply: The plunger remains at the maximum fuel supply position, and the governor fails to regulate, leading to increased engine speed. The governor cannot control the fuel quantity, the fuel rack and pinion may lack alignment marks or be incorrectly installed, the plunger might be reversed, injection pressure could be too low, excessive fuel is supplied to the cylinders, the linkage may be stuck in the governor's moving parts, or worn injectors may allow excessive return fuel from the intake manifold to be drawn into the cylinders, resulting in over-fueling. Solution: Excessive diesel fuel supply causing runaway is often indicated by thick black smoke from the exhaust pipe. Inspect components of the fuel supply system, such as the fuel pump, injectors, and governor, and perform necessary repairs after analysis. Oil Burning: Excessive clearance between the piston and cylinder wall causes oil to splash into the combustion chamber during piston movement. If the oil viscosity is too low, lubrication effectiveness decreases, accelerating piston ring wear. A blocked crankcase ventilation port increases oil pressure and return resistance. Aging or failed valve stem seals allow oil to enter the combustion chamber through the gap between the valve stem and guide hole under intake manifold vacuum, leading to oil combustion. Solution: Oil entering the combustion chamber is typically indicated by blue smoke from the exhaust pipe. Check the lubrication system components to determine if the oil level is too high or if the oil does not meet specifications.
