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Anyone know how to read a waveform of my sparkplug?

Posted: Wed May 30, 2018 9:10 pm
by PeterA
So I took this waveform shot when I was probing the pin at the ECU for the ignition pulse.

Does it look right???

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 8:38 am
by Charlescrown
A little more detail might help. It looks nothing like an inductive or hall effect signal to me.

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 1:25 pm
by PeterA
Well it looks similar to some i have seen online. Coil charges up thats when the line drops down, when coil is charged up..., it fires off. The big spike is the highvoltage pulse ans collapse of the magnetic field.
Then the horizontal line after that is the burn time of the spark. From here on i am not sure.


Its just a waste spark ignition system.

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 2:53 pm
by Charlescrown
I agree it looks like a HT plug firing. Not quiet the correct pattern but my question is how did you measure it at the ECU. It looks like the pattern you get off the coil HT lead.

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 4:58 pm
by PeterA
" probing the pin at the ECU for the ignition pulse."

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 5:08 pm
by immortality
I believe some of VL400's ignition module threads have info about this sort of stuff. Not sure if it's applicable to your application though.

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Thu May 31, 2018 5:23 pm
by delcowizzid
What model car and ecu what code in the ecu and what pin number .is it triggering a coil direct from the ecu

Re: Anyone know how to read a waveform of my sparkplug?

Posted: Fri Jun 01, 2018 8:44 pm
by pman92
A bit more info would help.
Im assuming this is coil negative and coil is driven directly by the ECU?
Whats the voltage scale? Is that 12v where it starts on the left before dropping down?
Then 0v flat line before the spike where it fires?
Normally the burn voltage is positive but if its waste spark you may be on the negative side of the coil hence the burn period being below 0v?
Not sure about the big wave at the end. Does look a bit odd.