Odd hashing in ignition waveform

:blink: hello everyone. My Name is Adel i know i got a girl name hahahha!! Today i scoped a customer's car , to find out he got a dead short coil over pack with 3 others coil packs misfiring intermittently. So i swapped all 4 with new oems. And scoped to confirm the fix just to find a odd hashing noise in the burn line of the waveform. I was :blink: could i got 4 bad coilpacks at once? I swapped again and there you are still same thing!!! The car seems run fine just concerned could be something got damaged since the customer neglected the shorted coil for so long. Thanks everyone!

So the car had intermittent misfires and when you scoped it you saw the waveform you posted. And with the new coils the car runs fine but you still have the same waveform? That's what you mean? Just trying to follow here

I have seen similar -- no ill effects.

No the car before exhibited a shorted coil waveform . but now got the odd noise/hash like in the burn line though car seems to run fine. I already gave it to the customer and asked him if any symptomes of misfires came back bring it back to me.

Thanks for the reply! Yeah i hope so he never have to turn back with same problem. Cuz what i understood from this hashing noise its like the spark droping out during burn time . bizzare isnt it?! Made me wonder what could ever cause such condition. My conclusion could be faulty spark plugs.

Like Andy said, I wouldn't sweat it too much Aside from those couple little twitches, the rest of the waveform looks textbook.

Here's an example I dug up of a primary waveform off a Jeep COP. Time base is different, but you can see some hash in the burn line. No problems here, just a characteristic of the waveform:

Like Andy said, I wouldn't sweat it too much Aside from those couple little twitches, the rest of the waveform looks textbook.

Yep, Tyler's hash looks a lot worse :lol: Think that's the problem with textbook pictures. Can't focus too much on them.

I have been thinking this one over, when the spark jumps during the burn time the arc tends wander around a bit for a whole load of reasons I think that is what is going on here.
Screen cap from a video of a Honda Cop I found onYouTube



Full video created by YouTuber SnaponDynodave

I heard a similar theory from an instructor, Jim Morton, who has an almost 3 hour seminar video on secondary ignition waveforms. He described that hashing in the burn line as the spark jumping from one molecule of fuel to the next until the mixture is burned.

sorry for the late reply. Been out of town for a while. And thanks all for the great Info's you guys been giving! I guess as Dylan said its seems normal. Later few days i followed the customer asked him if the car had misfiring issues whats so ever and he told the car runs fine no problem at all.

No problem! Glad to hear that the customer is happy