Knock sensors are really simple devices. It is actually called a piezoelectric device. It is a generator like an O2 sensor where it sends an analog AC voltage signal in which the frequency changes with vibration. So you would have to run a device to read frequency and watch what it does.
-I read this out of a dianostic manual.
-money making idea- someone make a aftermarket universal knock sensor with a meter to mount in the car.
My 94 Tbird SC has one, and I hate the damn thing. Anything can get it to retard timing. If you would tad the exhaust manifold with a wrench, while pointing a timing light at the balancer you could see the knock sensor kick in and pull timing. I know EVO guys have issues with their knock sensors too.
MSD sells a knock alert part # 8964; I have no first had experience with the device, so I couldn't tell you much about it. Good luck.