What causes a gasoline-to-CNG converted vehicle to stall when switching to gas?
3 Answers
The main reason is improper gas flow adjustment during the gasoline-to-CNG conversion, which requires readjustment. Below are specific maintenance methods for CNG-converted vehicles: 1. System maintenance: Regular system maintenance is essential for CNG-converted vehicles. Due to the special properties of the fuel used, a comprehensive leak test should be conducted on the gas tank every two weeks. 2. Driving habits: Proper driving habits are crucial for maintaining optimal performance in CNG-converted vehicles. During daily operation, ensure the vehicle is equipped with fire extinguishing equipment. If the vehicle will be parked for an extended period, the CNG should be depleted. Never service the fuel supply system in enclosed garages or workshops. 3. Routine maintenance components: CNG-converted vehicles may experience stalling during operation, which can be caused by improper cleaning of the air filter, incorrect fuel injection delay adjustment of the fuel injection simulator, or improper adjustment of the pressure reducer.
When driving a modified natural gas vehicle, I found that it stalls when switching to gas. There are several common reasons. The most significant one is an imbalance in the air-fuel ratio, meaning the mixture is either too rich or too lean, leading to incomplete combustion and stalling. For example, a faulty or improperly adjusted pressure reducer can cause uneven gas supply. Another issue could be clogged injectors, obstructing the gas flow. Improper initial tuning during the modification phase can also cause this, especially during the transition when the gas flow is unstable. It's recommended to inspect the gas system, clean the injectors, or adjust the proportioning valve. Another point is synchronization issues with the ignition system—old spark plugs might not keep up with the high volume of gas intake. If regular maintenance is neglected after modification, carbon buildup can easily clog the ports. Always check the gas cylinder pressure and pipeline seals before each trip to ensure no leaks. If a problem is detected, avoid forcing the vehicle to run and seek professional diagnosis immediately to prevent the risk of breaking down midway. For long-term conversions to natural gas, also pay attention to the compatibility of mixed fuels and avoid using low-quality gas cylinders to save costs.
Switching to gas and then stalling is often caused by a faulty pressure relief valve. The pressure relief valve controls the gas flow pressure, and if it's aged or incorrectly set, it can lead to an imbalance in the air-to-gas ratio. From my experience in car repairs, clogged nozzles are also a common culprit, as dust or debris buildup can obstruct smooth airflow. Additionally, if the electronic control unit (ECU) isn't properly calibrated, signal delays during mode switching can cause a momentary fuel cutoff. For modified systems, improper installation—such as loose pipes or gas leaks—can result in pressure drops and subsequent stalling. It's advisable to check the gas sensor, which monitors concentration levels; if the mixture is too rich, it may trigger a protective shutdown. For maintenance, regularly clean the entire gas path components and check voltage stability every six months to prevent generator output anomalies from affecting the system. If the issue persists, consider updating the ECU software or using OEM-matched parts instead of attempting DIY adjustments. Address the problem promptly to avoid accidents on the road.
