IAC mod on MS2 V3.0
 

Background, i've been changing over my MS2 V3.0 from Rx7 mode to Miata 1.6 mode. I have the IAC mod kit mostly installed, but i haven't got a good bead on what others have done with the diode. The Megamanual instructions seem to want me to use it in the wiring actually near the IAC itself. Is that the right way or best way to do it?

Also, the dual BIP373, how are people mounting both of them when they are tapped out on the heat sink. the FAQ mentioned stacking but that doesn't seem optimal. I think i can just attach them to the faceplate with the DB37 correct?

We don't run bips

thats what i get for going off the diyautotune FAQ?

so with that i should work in the "new fangled" spark version i see on here?

https://www.miataturbo.net/attachmen...ine=1354853098
https://www.miataturbo.net/attachmen...ine=1354853098

yea so my 1.8f lens doesnt like closeups, but anyway. Are people just using the stock ignitors then? I dont happen to have the stock one, so i have to source from a salvage yard. hence, why i was going to go with the BIP373. any reason no one opts for the BIPs?

ms2 with msi input mods.

https://www.miataturbo.net/attachmen...ine=1354887783

https://www.miataturbo.net/attachmen...ine=1354887783

okay, so now I have more questions than answers.

1. The diode goes from the middle prong to S12, correct?

2. this is the first time ive seen anyone jump tachselect to XG1

C. Kinda wish i knew what i was doing. Seems like thre are so many options that some people use, that others dont. Case in point. I have the capacitor mod done, which that picture doesnt, but it also has 5v going to C30, which ive never seen before. not to mention other things going on with that picture.

What Brain posted is just a user friendly version of this:

MS2-Extra Miata 4g63 Manual

If you've not seen people jumping Tachselect and XG1, you've not been looking hard enough, it's required for running a MS on an MX5 with these mods, it sets the board up for using a HALL effect sensor on the CKP input as opposed to say Tachselect to VRIN which sets it up for a VR sensor.

5v to C30 means you have a 5v pullup on the sensor for the CKP. If you saw people use S12C instead that just makes it a 12v pullup.

Either the "VR" or the "HALL/OPTO" circuit can be made to work. In fact, if you're using an MS3X, there is no "hall" option for the cam input. The cam input on the MS3X is "VR only", though we make it work.

Technically, the input which we now refer to as "hall / opto" was designed for use with breaker points in a distributor.

Thanks for the clarification Joe :)

okay so TACHSELECT should not be jumped to VRIN or OPTOIN but instead to XG1, okay got it.

so what about the fact i followed the diyautotune write up which showed this. I dont seem to see that going on in the above. Specically anything going to a pin on the daughterboard. Is it just a different way to run the pull up resistors then?

I apologize for the questions, but im new, and this is actually quite confusing.

https://www.miataturbo.net/attachmen...ine=1354891232

stop looking at MSI shit. wtf.

this is where i slam my face into the keyboard :crx:

i suppose that explains why things weren't making any sense to me. Going to desolder all the Ms1 mods i made then and start over.

:)

this might help, but it's still REALLY old: Megasquirt 2 Assembly - Miata Turbo FAQ

i cant really tell from the picture but is XG1 and XG2 still jumper together as well?

no. the jumper running to XG1 bypasses it

So, another question. Following the given guide above, i removed all the components that were not needed. I noticed "U2" is shown. I dont have anything for U2 which we just solder the holes. What WOULD go there out of curiosity?

the map sensor

oh, well i feel stupid now. i need to spend less late nights on this crap.

anyway. all the non used components are removed per the link.

i have all the jumpers, resistors and whatnot finished except the ignition resistor with the 2N2222 mod for the spark. I have a question first.

I DO NOT HAVE the stock ignitors. Is there any reason not to use the Dual BIP373 method as opposed to buying a stock ignitor? This motor is not in a miata.

one more question. For the IAC mod, i can run the diode from the middle prong of the transistor to S12, correct? as opposed to running that up near the IAC itself? Wasnt sure since i was going to send 12v power from another source than the MS2 so i wasnt sure if that would still work.

so the final question then. The diode for the IAC mod, i can run that from the middle prong of the transistor to the S12 to meet the requirement for fly back?

is the "spark output" the same as "sparkoutinv=" in Tunerstudio for the MS2? I want to make sure i have the settings for the improve spark circuit correct, and i didnt see the "sparkoutinv" option but i did see spark output and a drop down choioce of going low (normal ) and going high (inverted)

yes
yes
correct, change "spark output" to going high(inverted) for the 2n222a spark mod.

If you dont have ignitors, then yeah, you'll need to use those guys.



and yeah, flyback for idle mod to s12 (not s12c):

https://www.miataturbo.net/attachmen...ine=1355149515

awesome! i apprecaite all the help. i checked the thing out with a stim last night and its all working. I just need to add in the diode and she should be good to go. Then ill hot glue some bits to help survive the rally car's vibrations.

i called a miata parts salavage place and the ignitor is cheap enough so i wired it for the "improved spark circuit".

what car is this motor going in? the ignitor might be more of a pita to wire in than just doing the BIPs...

im gonna assume his rx7 with the B6 in it.

https://www.miataturbo.net/attachmen...ine=1327066127

lots of wires on that thing...

yea its for the rx7. alternatively, couldnt i use two MSD-6a as my ignitors?

some form of ignitor would still be required

so looking at the ignitor above, on a standalone megasqurit, where would some of those wires be going? such as #2, 5, and 7

7 and 2 would go back to the MS. those would be the spark outputs form typically the LED circuits.

5 is a 12v pull up for the tach signal.


so it would go:

1 - to coilpack 2 & 3
2 - MS spark output
3 - to coilpack 1 & 4
4 - tach output to gauge cluster
5 - 12v pull up from ECU for tach output
6 - ground
7 - MS spark output
8 - Power

so i could be fine with running a jumper from S12 over to a spare out then wire that over?

I wouldn't power the ignitor/coils through the same fuse that's powering the ECU. Only two wires from the ignitor should be going back directly to the MS, and that's the spark outputs from the MS.

last question then i guess is which output from the MS is for what coil. ie does spark a go to 2 or 7? Or is that a setting i can do via software?