What are the reasons for a diesel engine being hard to start and emitting white smoke?
3 Answers
Reasons for a diesel engine being hard to start and emitting white smoke: 1. Low engine temperature: If white smoke appears during startup in winter, it indicates the engine temperature is too low and hasn't reached the optimal state. In this case, simply wait until the engine warms up to normal temperature before starting; 2. Water in the fuel supply system: Place your hand behind the exhaust pipe. If water droplets form when white smoke passes over your hand, it means there is water in the fuel supply system. In this situation, the fuel tank and fuel filter need to be cleaned again; 3. Low air pressure in the engine cylinders: If the engine emits white smoke at low temperatures and black smoke after warming up, it indicates low air pressure in the cylinders. In this case, inspect components such as the valves, cylinder gaskets, and injector sealing gaskets for any air leaks; 4. Low injection pressure: If the engine emits grayish-white smoke and the vehicle lacks acceleration power after starting, it indicates low pressure in the fuel injection system. In this situation, check the fuel injection pump and adjust the fixing screws of the connecting plate.
I've experienced several instances of difficulty starting diesel vehicles. White smoke usually indicates incomplete combustion of diesel fuel, most commonly occurring in winter when temperatures are too low. The diesel may wax and thicken, making the engine unable to ignite, resulting in white smoke emission. Another issue is injector failure - if fuel injection doesn't properly atomize and the fuel sprays out unburned, it will also produce billowing white smoke. Insufficient cylinder pressure, such as from piston or valve wear causing leakage, can lead to inadequate compression and hard starting. Water contamination in the fuel is another major problem, where water vapor evaporation appears as white smoke. Once when this happened to my vehicle, I quickly wrapped the engine with a heated blanket for pre-warming, which helped somewhat. Usually, choosing high-quality diesel and maintaining the fuel injection system properly can save a lot of trouble.
My old pickup truck always struggles to start and emits white smoke during cold waves, which is particularly troublesome. I reckon it's mainly because diesel becomes thick and less fluid in cold weather, preventing the fuel from burning properly, resulting in difficult engine starts and white smoke. Additionally, if there's a leak in the fuel system, clogged injector nozzles, or poor atomization, diesel is wasted and appears as smoke. Worn cylinder liner seals causing compression leaks can also lead to this issue. Furthermore, if water gets into the fuel tank or the fuel is contaminated, the water evaporates during startup, turning into white smoke, which is very dangerous. I recommend avoiding low-quality fuel, regularly replacing filters, and especially conducting a thorough inspection before winter to prevent problems.
