Most ignition coils are negatively fired.

While I don’t recommend using a 2204A for Automotive use, a custom probe for your HT-25 with a gradient of -10000 should invert the waveform and scale properly.

Hi Gruss,

My shop PC has 2 Ghz dual core and 3 GB of ram running Winows 7 Pro 64 bit, works very nicely with Pico.

Hi Jabsam,

From what I understand, the bumps represent the acceleration of engine RPM for each cylinder firing event.

You could use a sync probe or secondary lead on channel B as a reference point to help narrow down the faulty cylinder as shown here.