Why is it hard to start a diesel tricycle in winter?

It’s a well-known fact that diesel tricycles are hard to start in winter. Recently, many people have been asking: What should I do if my diesel tricycle fails to start easily in winter? Next, we’ll discuss solutions to this problem, hoping to be helpful for your daily use of the vehicle.

The difficulty in starting a diesel tricycle in winter is mainly due to

• Due to the recent low temperatures and rapid heat dissipation, coupled with the low crankshaft speed, the temperature and pressure inside the cylinder at the end of the compression stroke are too low to reach the autoignition temperature of the fuel. Generally, diesel engines require the temperature inside the cylinder after compression to reach over 400℃, with a minimum limit of no less than 350℃.
• The viscosity of the lubricating oil increases significantly at low temperatures, and may even solidify, which increases the starting resistance of the engine and prevents it from reaching the minimum speed required for starting (generally above 100 r/min).
• At low temperatures, the terminal voltage of the battery drops, its capacity decreases and it becomes undercharged, which prevents the starter motor from reaching the required cranking speed when driving the crankshaft—or even from turning it at all.

What should I do if a diesel vehicle fails to start easily?

• Preheating should be performed in low-temperature seasons.The main reason affecting the starting performance of a diesel engine during cold starts is its failure to reach the compression ignition temperature of diesel fuel. To address this issue, hot water can be added to the engine’s cooling system for preheating, which is an effective method to improve starting performance.

Detailed procedures are as follows: Continuously add hot water (allowing water to flow out of the cylinder block) and gradually increase the water temperature for preheating. Close the drain valve when the outflowing water reaches a relatively high temperature. In addition, an open flame such as a blowtorch can be used to heat the oil pan, so as to improve the fluidity of the engine oil and reduce the running resistance of the mechanical components.

• Improve the Sealing Performance of the CylinderOne of the differences between a diesel engine and a gasoline engine is that the former adopts a compression-ignition mode, which therefore requires the cylinder to have high sealing performance. When starting the engine in cold winter conditions, the sealing effect is poor due to insufficient engine oil between the piston rings and the cylinder walls, which may result in repeated starting attempts without ignition or operation. In some cases, severe cylinder wear can significantly impair the cylinder’s sealing performance, making starting even more difficult. To address this problem, you can remove the fuel injectors and add 30–40 ml of engine oil to each cylinder, which will enhance the cylinder’s sealing performance and increase the compression pressure during engine operation.
• Remove Air from the Fuel LineLoosen the bleed screw on the high-pressure fuel pump, and manually pump fuel to purge all air from the high-pressure fuel line; then, bleed the remaining air from the high-pressure fuel line completely.

Detailed steps are as follows: Loosen the fuel line connectors on each fuel injector, set the throttle to the maximum fuel supply position, and crank the engine until fuel gushes out rapidly from the fuel line connectors of each injector.