I have a project in which I am going to characterize the flow measurement curves of the 3000GT and EVO 8 MAFs by flowing air through a metered orifice, calculating the CFM through that orifice using a manometer, and recording the frequency that the MAF reports at that CFM.

My end state is determining at exactly what flow value each sensor clips out.

To that end, I have built a rig with the ability to interpose orifices of various diameter and read the pressures on either side of that orifice. The rig also has a mount flange for an EVO 8 MAF (which I know is really a Karmann Vortex volume sensor, not a "real" MAF)

Today I made the wiring harness for the MAF connector.

Looking into the sensor, I have (left to right)

Pin 1 - +5V
Pin 2 - Baro Pressure
Pin 3 - MAF signal
Pin 4 - +12V
Pin 5 - Ground
Pin 6 - Air Temp
Pin 7 - NULL

Pins 1 and 5 are connected to a DC power supply set to +5V.
Pins 3 and 5 are connected to an oscilloscope (the ground wire from Pin 5 is connected to both the power supply ground and the scope)

When I connect the power and blow air through the meter, I get no measurable signal on the scope. Changing the air volume make no difference.

When I connect the scope to a frequency generator, I get the test wave - so the scope works.

Does the MAF need +12V? Both +12 and +5?

Anyone ever bench test one of these things?

 

I mean if its on the plug, it's likely needed. This isn't a part where they can both out there for optionality.

I would try again with 12v on there and see what you get then.

Another good test would be to check the other signals. See if you are seeing air temp or baro with only the 5v hooked. Its possible its split on what powers what.

 

Aha!

 

awesome work! keen to see more on this bro