teckel:
Find the attached "NewPingTestA.zip" library and replace the existing NewPing.* files in your libraries/NewPing folder. The only thing that Test A does is replace the echo measuring with the default pulseIn command. Because you stated you can hear the sensor firing, we're going to first assume that the trigger is happening correctly and the problem is with measuring the echo. This first test should isolate the problem where we can then focus in on one area.Let me know what happens.
I still hear a bunch of ticks, and I mostly get "0 uS" output over and over again. Now and then, nonzero values appear:
7494 uS
...
41944 uS
...
8251 uS
...
26104 uS
I haven't found a pattern yet that can make it produce nonzero output.