Let me share what I think about this...
About the 1st graph
- 840 rpm, 840 revs/60s = 14 revs per second = 14 Hz
- cam sensor repeats signal each 2 revolutions, so I should expect a frequency signal = 14/2 = 7 Hz
- signal repeats itself every 0,13875 seconds, so f = 1/0,13875 = 7,21 Hz, so values match aprox
- reading 145/146 workshop manual (it's not on 156 eLearn!!!), cam signal drops suddenly each time sensor is is
poiting to the hollow in the cam wheel
- so, should be expected 2 drops each rev, or 1 drop per cam signal period, assuming one hollow in cam wheel
- but the graph shows 4 drops each period, 2 wide and 2 narrow
- the way I'm thinkking there should be 2 big hollows followed by 2 smaller ones, or cam sensor is gone
- how many hollows are in this cam wheel?
- am I thinking right?