If the air flow meter is bad, there will be unstable idling, weak refueling, black smoke, and may not be able to play (if you doubt it, you can unplug the air flow meter, and it can be played is that the flow meter is damaged).
The common failure of air flow meter is the line short circuit, broken circuit, or the air intake signal is abnormal, the failure will make the computer can not correctly determine the amount of air inhaled into the engine, and thus can not be normal injection control, resulting in a mixture of too thick or too thin, so that the engine runs abnormally.
Because of the engine idle throttle fully closed when the air intake and the car accelerated throttle diagnostic open air intake between the difference between up to 40 times more than the maximum flow rate of air intake can be up to 80m/s or more, the air flow meter should be able to accurately measure these changes in the range of the amount of intake, and in the measurement of the air does not impede the flow of air, as far as possible to reduce the resistance to air intake.
Expanded Information:
Precautions:
1, the sensor should be horizontally or vertically mounted (the direction of flow of the fluid should be from the bottom to the top) in the pipeline corresponding to the nominal diameter. piping.
2, when the compressed air flowmeter used as a flow control, pay special attention to the flow control valve should be installed in the back of the sensor, otherwise in the small flow rate is easy to produce a jet, resulting in flow control, the media flow rate and the valve opening inversely proportional to the failure of the phenomenon.
3, the flow meter in the installation of its upstream and downstream should be configured with a certain length of straight section.
4, the flowmeter can not be installed in a strong vibration of the pipeline, so as not to affect the measurement accuracy.
5, when the flowmeter near the high-power motors, in order to avoid industrial frequency interference, in addition to the signal transmission cable to increase the shielding, the signal transmission method should try to use DC signals.
Baidu Encyclopedia - Air Flow Meter
Baidu Encyclopedia - Air Flow Sensor