04 1.4 manual Fukang valve problem

According to common sense, just adjusting the valve has little effect on idle speed, but the valve clearance of Fukang old engine is a bit special, which is different from ordinary cars. Generally, the valve clearance is relatively large. The standard intake valve clearance is 0.2mm and exhaust valve clearance is 0.4mm, but the empirical value is 0.25mm for intake valve and 0.25mm for exhaust valve.

The influence of valve adjustment on idle speed is not obvious, but it still has some influence, because the valve clearance will affect the valve stroke, that is, the valve opening, and then affect the intake air.

If it is found that the idle speed has changed after valve adjustment, it should be a part related to valve maintenance. You can check whether the ventilation pipe above the valve cover is installed normally and whether the check valve is installed backwards. The ECU of the engine has an adaptation process to idle speed. You can run for a few days by yourself. If there is a problem, you can focus on checking the link between the pipeline of the idle stepper motor and the valve cover. If it is really broken, you have to clean the idle valve. Fukang's idle valve is fragile, and it will be damaged if you are not careful, and it is expensive. You should try not to clean it unless you have to.