How you set up will depend on the type of MAF signal...analog or digital and the scope you are using. There is no set procedure that will work for all applications or personal preference.
Some general guidelines for the 3223 and Pico 6:
Set time base for a two second screen.
Dial samples up the the max
You can use simple repeat trigger set to trigger on the rising signal of the MAF snap test, if it is an analog MAF. If it is a digital MAF, you can use an advanced trigger option to trigger on the frequency increase. Or...no trigger and just repeat until you get one in the buffer you like.
You will want to suddenly open the throttle plate to WOT from idle in neutral.. This initial intake fill should peak the MAF on most applications. This will not work on a drive by wire application.
If you use low pass filter, to clean up the signal, use it sparingly so as not to over filter and obscure the true peak or distort the result.
Tap into the MAF signal wire and TPS signal with the other channel. Ground both to B-. This will allow you to be certain you had a good snap throttle opening for the test. This makes triggering much simpler too, especially for a digital MAF.....simply trigger off the TPS rise
(The Picotologist) http://www.autonerdz.com
THE PicoScope Automotive Authority
In North America