I just noticed the scope shots in post 31. I didn't see that earlier at work...they block some attachments...nor did I see it when i posted my most recent post.
That said, looking at it now, I definitely would try to move the sensor to monitor the tooth tip, the long axis of the sensor on a radial line from the wheel. That'll give you some dead time between pulses similar to what you see from the sensor at the missing tooth.
Another thought is if the buffer circuit is slow compared to the signal frequency, at some speed the buffer won't be able to follow each pulse and the ECU will get confused.
So my thoughts are: reposition the VR sensor and make sure the buffer circuit has minimal phase delay throughout the operating frequency..I believe awhile back you said the sensor frequency went up to 3 kHz? (@5000 RPM)
Perhaps the wheel has some axial runout (along the crank centerline). The change in gap from the sensor to the wheel would cause the amplitude change.
Moving the sensor as I suggest will eliminate that amplitude change unless, of course, there is also radial runout.
george
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