Calibrating the MPGuino is a time consuming task for me. It seems to go on forever,
because there is two variables which you can play with. The inj. delay and the uSec/litre.
I tried to find shortcuts to make the calibration easier. I found the flow rate for my injectors from the web. Don't know how reliable that information is, but I will use it just for starters.
But the injector delay was an unknown mystery.
So I tried to measure the injector opening and closing time by "recording" its sound with a pietzo sensor ("microphone")
I attached the pietzo to the injector with tie-straps and connected it to a scopemeter.
I also connected the injector voltage signal to the other channel of the scopemeter, so that I can compare them at the same screen.
I found out that the injector opening seems to take longer time than closing.
I'm assuming that the two "bursts" in the sound waveform comes from the injector hitting the open position and the closed position. The beginning of the "burst" is when it hits and the "burst" itself is just the echo of the sound
Then I carefully measured the tickmarks on the scope screen and I got that the injector voltage pulse is 2,68ms long and time between the open/close sounds is 1,80ms long.
Then the total injector delay would be 0,88ms, Right?
I took some other samples and the result is the same.
At the moment the inj. delay setting is 980 in my MPGuino and it seems to give little bit optimistic results, so I think the 880 sounds reasonable
I just have to drive a little more to get some results, then I know more.
How does this sound to you? Do you think this sound method is sound?
