Where is the fault when the EFI motorcycle has unstable idle speed and is prone to stalling?

[LeIsla]

Unstable idle speed and easy stalling of an EFI motorcycle may be caused by air passage blockage, intake manifold leakage, or sensor failure. The specific reasons are as follows: 1. Carbon deposits in the throttle body, air passage blockage: Carbon deposits in the throttle can affect the opening degree and the intake air volume, causing the engine speed to fluctuate between high and low after cold start, making it very unstable and accompanied by shaking. If the throttle is too dirty, it needs to be cleaned. Generally, cleaning can solve the problem of unstable idle speed. 2. Low fuel pressure, intake manifold leakage: Such as clogged fuel injectors or fuel lines, insufficient fuel pump pressure, or failure of the fuel pressure regulator. This results in poor atomization and abnormal mixture ratio, leading to incomplete combustion and unstable idle speed. If the intake manifold leaks, it will affect the feedback data accuracy of the intake pressure sensor, causing the ECU to inaccurately control the intake air volume and resulting in abnormal mixture. This leads to unstable engine idle speed. 3. Sensor failure: Related sensor failures cause inaccurate control of the air-fuel ratio, such as intake air temperature sensor, oxygen sensor, throttle position sensor, intake pressure sensor, etc. The related sensors need to be replaced.