Throttle solenoid valve is noisy.

You should say EFI engine. Under the control of computer, the solenoid valve for fuel supply of EFI engine will keep on and off with the engine speed to ensure normal fuel supply and maintain the engine work. It is normal that the solenoid valve will make a crisp click every time it is switched on or off. But not too big. If it is too large, you can find other reasons, such as the noise from other valves, or sometimes the valve noise caused by the damage of the valve hydraulic tappet, or the low oil pressure, the oil can not reach the normal level, and sometimes it will be mixed with the noise of the solenoid valve, which will make you mistakenly think that it is all the noise from the solenoid valve.