Waveforms old CPS versus new. (Both OEM) I put the older Techtronic’s Oscope on the old sensor (pin2) to have a look and see. I did not have an external trigger so I expected to see the various pulses with different durations repeat every 360 degree revolution. I looked carefully at the peak-peak voltage and the shape/crispness of the waveform.
My initial reaction when looking at the old CPS was that, well it looked ok.
Ok, so I installed the new CPS and had a look. My first observation was that the peak-peak voltage was the same between old and new. There was however a noticeable difference with the cleanness/crispness of the waveform. With the new CPS, the scope was able to detect and then lock in on a clean trigger point. The waveform was more crisp and square. With the old CPS the signal was dancing left/right across the screen. Old, edges were rounding, new edges were sharp. With the new CPS, the signal was locked on the screen, no dancing.
Conclusion, the old CPS was marginal/bad. If the scope was having trouble `locking in`, it is safe to assume the DME was have difficulty too. I would be nice to have a database of know good waveforms to compare/contrasts.
CPS installed, reset code, let’s see what happens.