Hi there guys, I am yet to build a Megasquirt but I am looking at building an MS2 v3. What I am hoping to do is understand 100% what I'm doing with the rotary modifications necessary for the MS to run my ignition system before I make my purchase.
My plan is to run ignition first and upgrade to injection later down the line (perhaps). I wish to run either COP with 4 bosch coils and being run by vb921 drivers, or I will just run the standard FC coilpacks. I plan to run an un-modified FC crank angle sensor with the two VR conditioning circuits (lm1815) for my input to the MS. I have read the FAQ and much more but I'm not clear on a couple of things so here are my questions.

1. Inputs...
The CAS signal wires are run through the lm1815 circuits, however I'm not clear on where the outputs from the lm1815 circuits go on the MS, or which VR goes to where on the MS. This is the wire coloring for the FC CAS

red main trigger +
green home trigger +
white main trigger -
white/black home trigger -

As far as I know, the green and white/black wires just need to be grounded at the megasquirt and the red and white wires need to be run through the conditioning circuits. What I don't know is where the white or red (main trigger) wires go to on the megasquirt. If anybody could answer this that would be fantastic.

2. Outputs...
Ok, There's a couple of things I am unclear about here. I understand that you need a 47k pullup resistor and I understand how that is wired up to the diodes. What I dont understand is where the vb921 transistors are connected to if I wish to run COP with 4 ignition coils. If anybody could shed some light on this that would be great.
Also, I'm having trouble working out the wiring on my FC coil packs.
This diagram helps me understand how the FC coil packs are connected to the megasquirt


however I'm unclear on the FC coils wiring... I need to connect the wire G/Y on the leading FC ignitor to the injector pulse circuit of the MS modified with the pullup resistor, however I cant work out which wire G/Y is on my plug. I've been looking at FC wiring diagrams and it has just confused me more as information contradicts each other etc... I've taken some pics of the plugs on my coil packs in the hope that they can be labeled for me.
This is the wiring diagram I've used to try and make sense of it all



This is what it has told me that the G/Y wire on the leading FC coil is brown, which is what I thought was +12v for the coil? It has also told me that the red wire is B/Y and I dont know what the black which is seperate is.
As for the trailing coil, it has told me that L/Y is white, and BR/Y is red.





now I'm sure the way I have worked it out is wrong, can somebody please correct me

I'm pretty tired so if something doesnt make sense just tell me and I'll try my best to explain myself. Thanks in advance for your help!

 

ah! ignore my comments about COP, I think I've worked it out and I've drawn up this diagram.



can anybody confirm if that is correct?

My queries about the CAS and FC coilpack wiring still remain though...

 

is this diagram that I made correct? or do the outputs from the vr conditioning circuit go elsewhere? I may have settled on just using FC coils rather than COP, so now I'm just after information on which wires are which on the coil packs and confirmation on my diagram/s and any suggestions. Thankyou.

 

That won't work!

Where the 680.330's are put nothing just wire it without resistors.

Where the 4.7k is for the 2 leading coils put a 200Ohm there
Were the 2 4.7ks are for the 2 trailing coils put a 330Ohm there for both


Then that will work, use normal spark output (not inverted), and it will work.

Just note that even tho I could mechanically fit them inside the MS case, it would completely **** my VR sensor signal, causing RPM spikes way high (70000rpm at times).

For the bosch coils I use 3.4ms dwell seems good. And I have plans of scoping it within the next 2 weeks

 

Here is the correct circuit diagram

Tested and verified by me!



PS I use 9220061710 Bosch coils (EA falcon), which are very similar to the HEC715/716 that everyone seems obsessed with in Australia.

 

Ah thankyou very much! Can you verify the CAS diagram? I'm still very unclear about where the connections from the lm1815 circuit need to run to the MS.

 

Your diagram looks correct.
I have scoped this same circuit but have not run the engine yet to completely test it.

One thing to note is that for the circuit associated with the red wire, you should change the top .001 cap to a .01 and the 56k resistor to a 39k for the wankel rotary.
See:
https://www.rx7club.com/megasquirt-forum-153/official-rx7-megasquirt-faq-ms1-check-here-before-you-ask-your-question-658411/

 

cheers mate. If I'm running the standard VR conditioning circuit built into the MS2 v3 and running the extra VR circuit in the proto area, Does the output need to go to 'JP4' or Pin 11 on the CPU? I found a topic that states that it goes to JP4 on the circuit board rather than CPU pin 11. If someone could confirm that, it would be handy oh, and where on the board is JP4? what component is it near?

 

Hi;
The link above is the rotary FAQ - it says to use CPU pin 11 for both the v2.2 and v3.0 boards.
I have a v2.2 board and I don't think it even has a JP4 area - sorry can't help there. JP4 may be connected to CPU pin11 - if so, it is probably near to the CPU.
Cheers

 

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Hey Jobro, your diagram says 220 ohms, but you are saying 200 ohms in your post. So, I'm guessing 220 is the correct number?