【Fault description】
    The car into the factory when the failure phenomenon for the idle when the flame.
    【Inspection process】
    After the inspection found cold when the mixture is very strong, hot car after a little thinner. Also found auxiliary accelerator pump membrane leakage, spark plugs, two high voltage lines are damaged. Remove the carburetor, replace the film, clean the idle air plug, replace the spark plug and high voltage lines. At this point, whether cold or hot car, the engine is always running very thin mixture A comprehensive leak check, handle two leaks, or mixed gas thin. Then check the oxygen sensor, its normal work and can reflect changes in engine conditions. Check the idle speed cut off the solenoid valve, the two solenoid valves are working. And then check the exhaust gas recirculation system (EGR system), the system is functional and no signs of leakage. Because there is no car diagnostic information, can not really understand the car computer feedback system works. On the right side of the firewall there is a vacuum solenoid valve with two wires and two vacuum tubes. If the two vacuum tube connected, the engine running slightly improved, the mixture is also thicker. What is the role of the valve? How is it controlled? How does the engine control system work? How should the next test be done?
    In addition, the intake manifold vacuum is slightly lower, if accelerated, the vacuum increases slightly, up to 20 inches of mercury. Cylinder pressure of 147PSI (10.7kgf / cm2), there is no indication that the catalytic converter is blocked.
    【Fault Analysis】
    The vacuum solenoid valve on the right side of the firewall is a solenoid valve that controls the mixture. It regulates the vacuum and ignition advance angle to adjust the mixture during cruising. It has little effect on idling. The control voltage waveform of the valve is very similar to the waveform received by the hybrid control solenoid valve, but it does not receive a control voltage signal at idle.
    【Maintenance】
    The exact point of failure of the car is another vacuum valve leak and slightly adjust the mixture to adjust the bolts. After repair and adjustment, the car has been in compliance with the emission regulations, the normal factory.