Pressure sensor to detect spark voltage leak

Ask for and share advice on using the PicoScope kit to fix vehicles here.
Post Reply
picowight
TwoWaves
TwoWaves
Posts: 133
Joined: Sat Oct 26, 2019 6:45 pm

Pressure sensor to detect spark voltage leak

Post by picowight »

What ?
V8 doing in Cylinder pressure testing, noted strange drop out of pressure, occurring at the same time on every pulse. Checked battery and ground power to sensor - both consistent at time of drop out so what the heck is going on ?
Screenshot from 2022-03-18 19-58-44.png
Only when I looked at the COP sync and used the rulers to split into 8 did I notice that the drop out's were linked to coil firing
Pressure spark anomally.png
Then I realised that in order to avoid issues with hose removal I had used a threaded metal tube to link sensor to plug hole, so what I was seeing (I think) was the sensor shutting down as stray voltage from a coil grounding outside of the plug. Going to electrically isolate sensor from test tube in future as I'm sure it will not do my expensive scope any favours.
- but it does make me think about using a COP sensor on an earth at the cylinder head!

Post Reply