EDIS6 Coil pack and spark wire/cylinder assignment

[alhbln]

Hi,

after being confused for a little while i seem to have worked out the spark wire order for the EDIS6 coil pack. Assuming that others installing an EDIS6 coil pack might encounter the same issues, i have put some firing orders in a table below, hope it helps. Let me know if anything is wrong.

The EDIS6 coil pack contains three independent coils where the winding of each coil is tapped in the middle, basically creating six coil circuits (EDIT: the coils are not tapped, see chart in the next posts). The upper three coil terminals have a negative polarity, the lower three terminals are positive. I have assigned each bank to the positive or negative terminals, respectively used an even/odd assignment for the straight six example.

Enjoy,
Adrian

[alexander]

adrian, i will stand to be corrected on this, but i dont think the above description of the EDIS coils is correct.
in, say, an EDIS6 coil, there are 3 separate primary, and 3 associated secondary coils. each primary is connected to the common 12v input, and is individually earthed by the EDIS at the apppropriate moment. i dont think there are centre tapped, and i dont think there are effectively 6 coils. it is only 3. each primary induces a larger voltage signal in the associated secondary, and that coil is not connected to anything other than the two HT outputs. the current path is through the secondary, out one terminal through one spark plug, through the engine metal, through the other spark plug and lead, and back into the coil. yes, there is +ve and -ve in that HT path, but it is of no consequence which way around the plugs, in any particular pair, are connected to the coils. pardon moi if you only meant to assign them that way as a matter of convenience for connection. that doesnt make anything you said incorrect practically speaking; but i think the strict truth of the matter is just a little more general.

that, at any rate, is my understanding of the coil construction and connection.

regards
alexander

[alhbln]

Alexander,
you are fully correct, thanks for noticing. I was assuming that each secondary coil has a ground connection as in a standard single coil, but as you stated this is not the case for EDIS coil packs. The chart of the coils internal below should be correct.

Best,
Adrian

[DannyP]

Alexander, I hope I am not wrong, but I think you have something amiss. The coils charge when earthed, they fire when the earth is removed, I think. That is why the spark is so much greater on DISX systems. The individual coils allows enough time to FULLY charge each coil before the ground/earth is removed and the spark happens, no matter what the rpm.

We also need 1-6-2-4-3-5 for a Porsche 911 flat 6

[NITROPIXIE]

DannyP you are right in what you say. As the coil is earthed and has 12v supplied to it, it will create a magnetic field. As soon as the ground is taken away the magnetic field created collapses which then induces a current through the secondary coils. As there are more coils in the secondary than the primaries the voltage gets stepped up to around 40,000v and a spark is induced across the spark plug as it is earthed in the block.

[Westfield 11]

Has anyone done this exercise for the EDIS4 coil too? I spent a long time getting my car to run correctly when connecting the spark plug wires. I know some find this easy, but it was not that way for me. The online documentation is a bit sparse regarding this.......

[alhbln]

DannyP, i believe the flat 6 is wired as shown below. Westfield, sorry i dont have any experience with an EDIS4 setup.

[DannyP]

Thanks. Looks great to me!

[alexander]

lads, may the good lord strike me on the temple, with a bosch GT40 coil, if i am wrong, but i do think it is as i stated.
if you put a multimeter on the any pair of plug sockets on the coil, i believe you will find they are connected to each other, and that they are not connected to the low voltage pins at all. that is because they are the opposite ends of the HT coil. the voltage is induced in it just as the voltage is induced in the secondary of an ac power transformer. this is quite different to the construction of your old style coil.

i believe it is as depicted in adrian's graphic, which plainly shows the secondaries as not connected to the ground.

perhaps we are slightly as crossed purpose: when i say there are 3 primary coils and 3 secondaries, i am not referring to the number of turns in the coils, if that is how it reads. there is of course a ratio of something like 1:20 between the coils in the primary and the coils in the secondary.

regards
alexander.

[DannyP]

Alexander, your wiring theory is absolutely correct. All I am saying is that the spark happens the moment the ground of the primary is lifted, due to the collapsing electromagnetic field.

[alexander]

oh i see. sorry, i didnt mean to imply otherwise.
anyhow, after not participating on this forum for some time, it is good to have an opportunity to maintain my presence at the upper end of the all time most prolific posters.

cheers.

[Spockie-Tech]

Figuring out the correct coil wiring for *any* engine is fairly simple if you understand how the EDIS waste-spark works.

The Edis simply fires the coil outputs in order from TDC#1 over and over again.

If its an Edis-4, its just AB, AB, AB,
if its an EDIS-6, ACB, ACB, ACB *** Note unusual firing order for Edis-6, NOT ABC !!
If its an EDIS-8, ABCD, ABCD, ABCD
etc.

when I say "Fire", I mean releases the grounding for that coil, which as mentioned collapses the field and triggers the two plugs attached to that coil.

So what you want to do is when coil A fires, you want one end of it to be the cylinder that should currently be firing, and the other end (wasted spark) of it to be the one that is on the opposite side of the firing order (which will be TDC (minus advance) on the Exhaust Stroke)

So, the trick to remembering how to work it out is... you split the firing order in half and sit the two halves above each other with the coil pairs as headings... so for my engine (a Hemi 6) with a firing order of 1,5,3,6,2,4 then we go like this..

A,C,B (**Note unusual Edis-6 ACB Order)
------
1,5,3
6,2,4

so in this case...
Coil A goes to 1 and 6,
Coil B goes to 5 and 2,
Coil C goes to 3 and 4

Lets throw another example for an EDIS-8
- Chev small Block, Firing Order is 1,8,4,3,6,5,7,2

A,B,C,D
---------
1,8,4,3
6,5,7,2

Coil A is 1 & 6
Coil B is 8 & 5
Coil C is 4 & 7
Coil D is 3 & 2

and Edis 4 is the same as Edis8, but obviously just the first two, AB, AB etc.

Does that make it clear ? If you can get your head around that, then figuring out any engines correct plug wiring for EDIS is a snap.



** Edited with corrections for Edis 6 as pointed out below. Thanks !

[alhbln]

Caution, the EDIS6 ignition sequence is A>C>B (not A>B>C). The Hemi 6 example should be covered by the firing order example in the first chart for the 1-5-3-6-2-4 inline engines.

[Spockie-Tech]

It is ??

Admittedly the last 3 EDIS installs Ive done have been 1xEdis4, and 2 x Edis8. but I did an Edis-6 probably 6 months ago and I dont recall thinking that the ABC sequence was out of order at the time.

However, I have just looked it up on a tech page and you are completely correct, my mistake, thanks for picking it up. I will edit the above post.

regards

Brett

[alhbln]

I did a little do it yourself chart to document the spark plug wiring. If you have the fire order for your engine (as example 1-5-3-6-2-4) you just fill in each cylinder of the fire order in the sequence on the chart - presto!
If that works for you guys i could do the same with the EDIS-4 and EDIS-8 setup.