Secondary ignition capture question...

Hi everyone, I was hoping someone might be able to tell me if I have something set incorrectly on my Modis Edge. This capture is off a 1996 Silverado 5.7l. I have the pickup probe place between the coil and distributor cap.  What is causing this pattern to have this slope? If I zoom in the capture looks great but why is it sloping down from 35kv? Any help would be greatly appreciated. Thanks!

That is a very nice capture.

What you see is normal, the reason for that spark firing up so high, is due to increased resistance.

What is important in this case is that the firing KV ( Point of Plasma ) AND the Burn Time are the same as the others.  And in your case it is it looks pretty good.

On distributor engines this is common, BUT it can also occur on COP systems too/

This is an excellent capture too, from one of Mr. Danner's videos.
 

Here Paul is creating resistance by increasing the air gap, this put a heavy load on the coil and it is forced to output as much as it can.

If you noticed this everytime and the same plug, then there is an issue.



 

That's actually a really good test for a coil. Pull the plug boot off and see how much the KV changes by lengthening the distance to the plug. I guess I've always done this test if I suspected a "lazy coil" but I never cared to use a scope at the same time, would be helpful for those units with multiple coils on them.

When you have multiple coils on a bank and only 1 cop or a secondary lead.

Run Aluminum tape across the coils and put your secondary lead (Clip-On Style, or wrap the cop wand) on the end of the tape, ( try and wrap all over the coil and daisy chain them together)  Use another channel for a sync.

I've used aluminum tape on a v8 engine with cops...1 Channel...8 spark traces!!!!!!



 

• Paul P. post=63970 userid=7093

When you have multiple coils on a bank and only 1 cop or a secondary lead.

Run Aluminum tape across the coils and put your secondary lead (Clip-On Style, or wrap the cop wand) on the end of the tape, ( try and wrap all over the coil and daisy chain them together)  Use another channel for a sync.

I've used aluminum tape on a v8 engine with cops...1 Channel...8 spark traces!!!!!!

 

I Need to try that, great tip