Am doing something slightly different with my setup, as I am required to be able to swap back to stock computer as well, so am building my harness to plug into the stock location. I have done something like this with my MX-5 as well, but then ran extra wires, like boost control and wideband where those can be unplugged and replace the narrowband wire input

I used the following images to build myself a pinout guide, as well as the Adaptronic pinout guide, but that is for the Turbo II, so compared the turbo and non-turbo pinouts to build my guide below.




This is my resulting guide that I made. Green just means I have soldered the connection, red is not.




The parts highlighted in gray are what I currently have questions on.

The MS3 has two different idle wires, "PWM Idle" and "Idle valve" and not sure what one to use. https://www.aaroncake.net/rx-7/megasquirt/WireMS3X.asp says FIdle off of the mainboard which is the PWM Idle, Want to confirm this as one of the pictures says Idle valve but text made refrance to PWM. I am aware of the diode I need to install with this one too

For the CAS, this is the shielded wire that is in the harness? Am I still to be using the Cam Input anywhere? 1P and 1N are just grounds? Which one gets the white and what one gets the black wire? The shield sheath gets grounded?

1M<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}-->Coil with Igniter (Trailing) IGI-T. This one seemed to be used in the Adaptronic pinout, I do have one extra spark output, E that I could run to it, but I already have the three wired up, is this used?

1J initial set coupler - This is unused, as it only goes to that plug in the engine bay to set idle right?

1H Water temp switch - I already have Water thermo sensor in 2I, what does this do? Adaptronic says it is also a water thermo sensor, but then uses this for a knock sensor? Am guessing it is used and they just run that wire to the knock sensor instead? What is 1R then used for? Should I wire this up to a spare input for knock sensing?

1G Neutral switch - use spare input?

1E A/C switch - use spare input?

2H atmospheric pressure sensor - on the Adaptronic, they have this one wired up to their tach output, and calls it an ATP?

The stock computer seems to have an always on power source, but I only see the 12v power input on the MS3, so that does not get used either?

With this setup, the injectors will all have power with current wiring? Do I need to use Bank 1 and Bank 2 injector wires with this setup?

Other notes if anyone sees anything glaring:
I wired up the VVT wire to control port solenoid valve
PT4 is going to read the mileage switch to get VSS speed
The nitrous output will light up the shift up indicator

All of my current unused inputs:
Main Harness:
Inj Bank 1 (2)
Inj Bank 2 (2)
SPR3
SPR4
IAC1A
IAC1B
IAC2A
IAC2B
SPARK A (brown wire), wire guides says <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}-->Ignition Output (MS-II)

MS3X Harness
Spark B
nitrous input
table switch in
Data long input
Spare ADC
EXT MAP
INJECTOR H
NITROUS OUT 2
PWM IDLE
CAM INPUT
EGO2 - Could I use this to have both narrowband and wideband connected, or at a later date, a wideband on each exhaust port?

 

yep, the stock ecu uses it for setting up the idle, the MS3 doesn't need it

the stock ecu uses this to know when its warmed up, it switches around 65c, the MS3 doesn't need it, it just shows how antiquated the S4 ecu is!

probably, again most new ecu's either have something internal, or take a reading when the key is on and the engine is off. Ms3 probably could use it if you wanted, but the default is probably something else

 

So here is the next issue.

Arroncakes writeup states the following: (if someone knows how to tag someone please let me know)

The issue is that the premade harness I have does not have a pin 12, it is empty. I took the cover off and there is nothing going to it. The only other shielded wire that I can account for was pre-made to go to pin 1.. is this a typo?

Edit- I think I might have found the issue, all of the instructions make reference to DB37, just not which one. Might want to clarify the MS3 or MS3X DB37 connector

 

Are you doing just a ms3 or ms3x? you have to build the G senor circuit(2 tooth wheel) in the proto area and internally connect to and use the spare pads(spr 3,4) to get the pins on the db37 as there is no second cam circuit on the MSV3.0 mainboard . ms3x you use the cam circuit for the g sensor. The 24 tooth NE main trigger wheel goes to the circuit on the main board.

 

I got it working, now the issues I have is I had to set Trigger #1 Angle to 180 degrees, and tachometer is maybe showing half compared to Tunerstudio

The rear trailing plug is not firing at all, so is this maybe why I have half tach speed?

 

Also found that trailing spark plug is not firing. Is this maybe why my tach is reading half?

 

maybe, the tach is just driven off the coil like any other car

 

Another follow fix, and another question.

I had used a mix of the adaptronic pinout, and what Megasquirt info I could find.

1U was labeled output 4 on the adaptronic, and 1M was labeled spark output 3.

I had gotten confused because I had also found this for the FC:


So I had connected C to 1U, and D was unused (I would like to redo those wires to run COP like the RX-8 in the future though)

I was getting half tach speed, and the rear trailing plug was not firing at all, but the car overall was running well.

I pulled my adaptor harness out again, and rechecked the wires to the pins, and found that Spark C and D were swapped on their pins. The harness was premade, and while I initially was making the adapotor harnes, did not think to double check that side, so is my fault. I made the mistake as well, as the words written on the wires were so worn out that it was difficult to read a "C" or a "D" in the smudged font.

Car cranked just fine and now everything is still running well.

My only concern now is that I still have to set the "Tooth #1 Angle" has to be set to 180 to time it to -5 degrees. So it is making me think that I still have something backwards somewhere. Does anyone have any idea what might be swapped, or as it is running well, leave as is?

 

Did you have to add a diode into the harness for the BAC valve?

Aaron's write-up indicates that you need one, but I'm wondering if the stock harness already incorporates this part.

 

I did use the diode, just had it integrated in the megasquirt to stock pinout adaptor harness itself