[diesel_john]

Two different instruments. The piezo I was talking about was a timing light for diesels which I used to verify diesel timing before each sound test. Although the piezo lined steel ring was designed to trigger a timing light from an injector line, I looked at the raw signal on a scope and it clearly showed the entire injection pulse. True a piezo pulse does decay over time and true there is ringing on top of the signal caused by the needle bouncing on the seat in the injector among other system resonances, never the less the entire injection event can be discerned.