Air Flow Meter

The air flow meter we tested was a L Jetronic type, the moving vane type that uses a potentiometer to vary voltage signal, as the incoming air moves the vane.
The only piece of equipment we need to test this is an ohm meter, to measure the resistance at the different opening angles of the vane.
After plotting the graph of angle vs. resistance, I found that there was a general trend of, as opening angle increases, the resistance of the potentiometer increases. But because we measured in small steps, we were able to see the fluctuations of resistance, but the general trend was increasing.
what this means is that as resistance increases, the voltage signal back to the ECU decreases, and therefore can calculate the volume off air flowing through the intake.
Types of Air Flow meters;
-L Jetronic: Incoming air moves a vane which turns a potentiometer which changes resistance and therefore changes signal back to ECU.
-LH Jetronic: Incoming air passes over a hot wire, this cools the wire a certain amount, so a certain amount of current can get to the ECU.
-D Jetronic MAP sensor: Intake manifold pressure acts on a diaphragm which varies resistance which changes the signal to the ECU.
-Karman Vortex Type: Ultrasonic waves pass across the diameter of the airflow meter. Incoming air upsets these waves to a certain degree. A signal is sent to the ECU, varying on how upset the waves are.