Checking Secondary Ignition

[karmarepair]

I want to make sure all 4 plugs are firing. I have them all out, but placed where they ground to the block. Fuel off. Should I pull the prop through by hand or use the starter? Any other safety tips?

[WesRagle]

In the past I would have said pull through by hand. However, since Sonex obsoleted ACV-A01-27 and replaced it with ACV-A01-23 you may well have to use the starter.

Why don't you contact Sonex technical support and see what they say. It would be interesting to know what the "time out" is for the new module to stop firing.

Any other safety tips?

Make sure all plugs are grounded, regardless of which plug you are testing. This because there is only one secondary winding per coil. The plugs are in series. If one of the plugs is un-grounded the spark might complete the circuit by arcing inside the coil causing coil damaging.

Good Luck,

Wes

[SNX1508]

Make sure all plugs are grounded, regardless of which plug you are testing. This because there is only one secondary winding per coil. The plugs are in series. If one of the plugs is un-grounded the spark might complete the circuit by arcing inside the coil causing coil damaging.

With the ground for each plug being the engine block the plugs are in parallel, still a good idea to ensure that at least one plug is grounded during testing though.

[WesRagle]

Good Morning Terry,

With the ground for each plug being the engine block the plugs are in parallel

I don't think that's right.

I was testing fault conditions in the secondary ignition system and decided to disconnect one of the plug wires on the coil being tested. Ref. https://sonexbuilders.net/viewtopic.php?f=66&t=6148&start=90#p57842.

Here is a copy of some email correspondence with DynaTek Technical support.

I wrote:

HI Scott,

I do understand the basics of how a step up transformer works. Just so I understand, when you say "dual output coils both spark plugs will share a common secondary winding" does that mean that the same circulating current in the secondary flows through both plugs? Does it mean that the two spark plugs are basically in series with the single secondary? I understand arcing to the core, but what does arcing " internally" mean? Primary to secondary? I'm just confused.

Thanks,

Wes

DynaTek replied:

Scott Valentine (Dynatek)

Feb 28, 2024, 1:13 PM PST

Correct, one end of the winding is connected to one spark plug output and the other end is connected to the other plug output. Both plugs fire at the same time with the majority of the voltage going to the cylinder under compression. As for the arcing I was just giving possible scenarios. Without witnessing it I cannot really say where it was arcing to. I would just try to avoid that situation altogether.

Regards,

Technical Support
Toll Free: 800-928-3962

Put another way: Current flows from the engine block to the center electrode of one plug, then through the secondary of the coil, then from the center electrode of the other plug back to the engine block.

That's what I meant when I said in series.

Wes