Elantra's idle speed is high. What happened?

The normal idle speed of EFI engine is determined by idle speed control valve. According to the engine speed, temperature, throttle switch, air conditioning switch and other signals, the electronic control unit will increase the intake bypass passage of the idle speed control valve or directly increase the throttle opening after calculation, thus increasing the air intake and improving the engine idle speed.

If there is oil pollution and carbon deposition, the idle speed control valve will jam or the throttle valve will not close normally, which will make the electronic control unit unable to adjust the engine idle speed accurately.

Extended data:

Precautions:

1. When air, gasoline vapor and combustion exhaust gas that should not enter enter the intake manifold, the mixture is too rich or too thin, which makes the engine burn abnormally. When the air leakage position only affects individual cylinders, the engine will shake violently, which has a great influence on the idle speed of cold cars.

2. Fuel pressure fault The oil pressure is too low, the fuel sprayed by the injector is in poor atomization state or the sprayed fuel is linear. In severe cases, only oil droplets are injected, and the fuel injection quantity is reduced, so that the mixture is too thin, the oil pressure is too high, and the actual fuel injection quantity is increased, so that the mixture is too rich.

3. Inaccurate ignition advance angle Because sensor and line faults are indirect causes of unstable idle speed, the control unit sends out wrong instructions, which makes the ignition advance angle incorrect or causes the ignition advance angle to fluctuate in a wide range.

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