Why does the engine idle shake after converting to gas?
2 Answers
The reasons for engine idle shake after converting to gas are as follows: Severe engine carbon buildup: Engine carbon buildup is the main cause of car shaking. When there is excessive carbon buildup inside the engine, the gasoline sprayed by the fuel injector during cold starts will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts, which can easily cause shaking. Ignition system malfunction: Excessive carbon buildup on the spark plugs or excessively large ignition gaps can lead to ignition failure. Fuel pressure issues: Abnormal fuel pump supply pressure or incorrect readings from the intake pressure sensor can easily cause poor fuel pump performance, leading to vehicle shaking.
Speaking of engine idle vibration after CNG conversion, I've had firsthand experience—it felt like driving a massage chair with all the shaking. The issue lies in the improperly adjusted gas-to-air mixture ratio. Natural gas burns differently from gasoline, and without precise coordination, uneven combustion at idle causes vibrations. Additionally, pay attention to the ignition system: worn spark plugs or aging high-voltage lines produce weaker sparks at low RPMs, exacerbating the problem. Post-conversion, the control system needs to adapt to the new fuel, but if self-adaptation fails, the ECU (the engine's brain) can't optimize parameters, leading to unstable idle. I recommend promptly checking the gas regulator and oxygen sensor to prevent carbon buildup from affecting performance. It's best to return to the conversion shop for professional fine-tuning—don’t wait until it worsens, as this can avoid shortening the engine's overall lifespan.
