Hot Wire Airflow Sensor
Note: i did test this type of sensor.
www.autospeed.com
This sensor has 3 main wires (5volt power, earth, analogue signal)
when the engine is at idle and the throttle butterfly is closed the output voltage of the sensor is around 1 volt. When the throttle butterfly is fully open the output voltage of the sensor is around 4.5 volts.
To test this sensor you must set your voltmeter to read 20 volts and place your negative probe on the earth wire of the sensor and your positive probe on the output signal wire of the sensor.
you must then hook up a 5 volt battery supply to the 5 volt power terminal and the earth terminal.
once you have done this, you need to get a hair dryer or something to blow into the sensor the give you different voltage readings.
This has a thermistor inside of it and when the revs go up increasing the airflow, the thermistor cools down and makes the resistance lower. this means there is more voltage to ecu which tells us the throttle is opening more.
Vane/Flap type air flow sensor
www.kjfgb-hteyc.tk
this type of airflow meter has also got 3 main wires (5 volt input, output, earth)
to test this sensor you must set your voltmeter to 20 volts, place your negative probe on the earth terminal, place your positive probe on the output terminal. you must then have 5 volt battery supply to the input terminal and the also connect it to the earth if the sensor.
once all of these thing are hooked up slowly move the flap on the inside of the sensor, your voltage should slowly go up.
when the flap is closed it thinks the engine is at idle and is only sending 1 volt to the ecu, when the flap is fully open it thinks the engine is at open throttle sending around 4.5 volts to the ecu.
i created a graph at the different angles i had the flap open at and the voltages i was reading:
| vane angle | voltage output |
| 0° | 2.2V |
| 20° | 4.7V |
| 40° | 6.8V |
| 60° | 7.6V |
| 80° | 8.1V |
| 100° | 8.5V |
| 120° | 9.4V |
as the flap opens more, it creates a greater voltage output to the ecu
No comments:
Post a Comment