Primary Ignition on Distributor Ignition

Hey all,
I am taking Primary Ignition Voltage, Current, and I have Secondary Ignition primarily for a sync to #1.
This is a V6 with Distributor. I am backprobing the coil.
I am wondering why I dont see 6 Primary Ignition events before my Secondary waveform triggers #1 again.
I know I should put more time on the screen, but I have included a picture. It makes it look like I am only seeing 2 different ignition events to me, but I would expect to see all 6.
Channel C is on the top with Secondary clamp pick-up on #1
Any thoughts welcome!

It might be that your secondary probe is close enough to another plug wire to pick up some unintended noise from other firing events. Your green trace kinda suggests this by the way the right-most event has less detail than the left-most.

If possible, you can try to separate out the plug wires to get some distance between them and your secondary probe. Or, you can compare the amplitude of the secondary events. The tallest one will likely be your sync. The others are likely just interference/noise.

720* in ~46mS is about 2,600 rpm. Was the engine turning that fast when this capture was taken? I'm guessing not and that Tyler is correct about the secondary probe picking up more than one cylinder.

If you've got an rpm pickup from an automotive DMM use it for a sync signal instead of the secondary probe. It's easy to tell the difference between the firing event and noise with those. Yellow trace is taken with one on a waste spark 4 cylinder. Big spike on the left is the firing event. Medium size spike is the waste spark and the two small ones are from the other coil pack.

That seems very likely, that I was picking up ignition events from other near by wires with my sync. (not sure what happened to that picture??)
I have captured below, primary ignition synced with fuel injector.
Now it looks like I am seeing 3 different ignition events, but I was still expecting to see 6.
Any further thoughts?

The vehicle may be firing the injector every 360*. Was the engine running at about 1,000 rpm or 2,000 when that capture was taken?

I think Matt T has solved your mystery.

Was the engine running at about 1,000 rpm or 2,000 when that capture was taken?

9 ignition strikes in 180ms = 1 strike per 20ms
3 strikes per revolution = 60ms per revolution
60,000ms/60ms =1000 rpm


I avoid using injectors as a sync. There are too many variables, as to when and how often they fire.