This is a high def version of a video I posted a few weeks ago. When I uploaded that video I used a compression algorithm that wasn't quite right, and this version should be easier to watch. Thank you to Curiosity and others for noticing. Other videos of labscope diagnostics are in the works and should be ready in a few weeks.
This video is the first of a video set describing the power of an automotive labscope (in this case a Picoscope) as a diagnostic tool. This first video goes into an introduction, followed by a practical description of how to perform a relative compression test using starter motor current draw to estimate cylinder compression. The theory behind the test, the limitations, and why it works are described in some detail.
For part 2, of this series, discussing secondary ignition waveforms, go here
https://youtu.be/DbV3EYIWT_k
This video is an amateur effort, published in good faith but with no guarantees as to accuracy or safety. DIY auto repair can be inherently dangerous, so consider those risks before deciding to try and repair your vehicle. Any misadventure you encounter if you decide to repair your vehicle is your responsibility.
Four stroke engine gif recorded with permission from Wikimedia commons, published by Zephyris under CC3.0 license.
https://commons.wikimedia.org/wiki/File:4StrokeEngine_Ortho_3D_Small.gif
Music “The Engagement” by Silent Partner, used with permission under Youtube audio list.
