Question on current ramp testing a cop.

Hi I was wondering if anyone could tell me is this a good wave form?  it’s from a good running car that I unplugged a coil to see what a difference it made. I’m using a fuse that the cops and injectors use. And use a low amp clamp with a fuse current loop. Just asking for future tests. And yes I know the wave form is upside down. Thanks 

The way you set the time base and current range will allow you to do some comparison between multiple coils. Obviously in your capture 1 of the coils is missing. You can see the amperage draw of each coil and see the consistency of the coil activations or their absence.

You would need to change at least time base and with this sampling rate to analize details of single coil's performance like saturation time, CEMF, overshoot.

Also you may consider to use peak detect on longer time bases like the one you show here.with the SO scope

Ok thanks I appreciate the reply. I’m just starting out using a scope what does peak detect do differently? Also with the one coil i unplugged is that what you would see with a coil that doesn’t put out any spark or would it just show a lower current ramp? Thanks

Peak detect puts the scope in a mode where it applies the highest available sample rate. Especially when scoping ignition events (and other fast signals)this high sample rate is necessary for true and detailed graphic representation'

A failed coil with no current flow will show up just like in your previous capture. A coil with high primary resitance and hence low current flow also will stand out, as well as a shorted secondary may be seen.

But: the coil's current draw may be perfectly fine amd yet an ignition problem can be present. You would need further testing like primary and/or secondary voltage tests to find these kinds of problems.

Thanks