Serper3

iTrader: (3)

Hi guys, i really need some help trying to figure out how complicated the Megasquirt is going to be on my 99. i promise i read and read, but since most of the MS info is for the na's, its difficult to find answers to my questions.
i am going to be running begi-s kit (already received kit ). i have a intercooler setup i am going to be putting together. i also have an lc1 with nb gauge and a boost gauge.

i dont think i can tackle building the whole ms myself. partially because i would prolly **** something up. partially because i dont have much time being a full time student and working a lot. (to pay for this stuff) i emailed diyautotune to see what they could do in terms of something that will get me as close as possible to a MSPNP for the 99, and this is the email i received:
Here's a quote for a Megasquirt modified with the '90-'97 Miata
ignition
input and output mods, and a 18" pigtail harness with a Megasquirt
connector on one end and the other end unconnected. You will need to
make the rest of the parallel installation harness on your own. This
assumes you will be using a second set of CLT and IAT sensors for the
installation - there's been a few people who have managed to get
sensors
to work in parallel on '97 and earlier ones, but I haven't seen any
documentation on specific values you need for '99 and later cars. The
MegaManual has a general how-to guide for sensor sharing but it's a bit

complicated:

http://www.megamanual.com/v22manual/sharesen.htm

Now here's the quote.

MS1357-C $335 Assembled Megasquirt-I with V3.57 PCB
MOD_13571GDSM: Preconfigured Miata / 4G63 ignition output: $50
JimStim-C $95 Assembled JimStim diagnostic board
StimPower $7.50 Power supply for JimStim
MSPiggy $48 18" pigtail wiring harness
CLTIATwPiggy $17.75 Coolant temperature sensor
IATwPiggy $22.25 IAT Sensor
38NPT-Bung_S $8 Steel Bung for mounting IAT sensor (Alumimum or
stainless also available for $9)
TuneCable $5.50 6' DB9 tuning cable
USB-2920 $20 (Only needed if your laptop doesn’t have a true DB9
port)
Subtotal without wideband-- $609

i know i need a CAS from a 94-97 miata, but what else would i need. i am hoping to make the MS capable of simply unplugging for smog purposes. i am curious though as to what i will need in terms of making the adapter to run the MS in parallel and what other sensors i will need, or can i make the stock sensors work like the email i received states.
thanks alot though for the help guys, i am really looking to get this thing figured out so i can have some fun with the turbo!
Henry

Joe Perez

iTrader: (8)

No, you don't need an NA CAS. If you use the MS2 CPU, you can run as a full standalone with the unmodified factory sensors. The mods to the MS itself will differ slightly from most of the writeups (which are geared towards MS1 with NA sensors) however it's been done by a couple of people with great success. The only sensor you'll need to add is an open-element GM IAT sensor in the intake tract post-intercooler, but that goes for all MS builds on turbo cars.

Do it this way, and you can build yourself an adapter harness to go from DB37 to the factory connectors, and run without cutting a single factory wire. If you feel that you need to remove the MS for smog, just pop the factory injectors back in, plug in the OEM ECU, drive around for a week or two to satisfy OBD-II (while out of boost) and do the thing.

Also, don't buy the pre-made 18" wire harness. It's pinned for a "universal" build, not for a Miata build.

And I'd suggest the 3.0 PCA rather than the 3.57. Not only is it cheaper, but it's easier to mod.

Serper3

iTrader: (3)

Thank you very much for your reply! i was under the impression though, that i need the stock ecu to control ac and my alternator? for doing what you are suggesting would i have to delete my ac and get an na alternator to run full standalone?
are there instructions for modifying the MS to fit my needs online? are they as intensive as the other mods illustrated by braineak on his sticky thread?
everything sounds good though in terms of being capable of going back to stock ecu. if i dont get the pre-made 18" wire harness, what would i need to buy, just the db737 to...? and this would only be the case if i go full standalone and not in parallel.. right?
yea the 3.0 sounds good! cheaper is always better .
i am just paranoid that i am going to get this stuff, and if i have to do too much to it to get it to work... well the more stuff i have to do, the less likely it will work
thanks for the help though and i am really hoping to order in the next few days but i want to be sure i order everything i need. using stock cas is also awesome because its less work and money to find and buy an older cas!
thanks again in advance for your help!

Joe Perez

iTrader: (8)

Both A/C and alternator control are covered in the Sticky thread at the top of the Megasquirt Forum which is entitled SUPER Important Megasquirt Threads, as they are super important. Specifically, here is a link to it: https://www.miataturbo.net/forum/showthread.php?t=17498

I haven't yet written the '99-00 chapter for the A/C yet as I'm waiting for Abe to supply me with a part to test (lazy SOB) but it looks to be just as easy as all the rest of them have been.

You do know that the Miata is a convertible, right? Don't really need the A/C.

Yes.
Yes.
Nothing. The MS kit comes with a bare DB-37 connector and backshell, and I assume you can solder, so just wire it to the factory connector(s) that you come up with.
It is a bit complex, I'm not going to lie about that. If you've never used a soldering iron and don't know how a multimeter works, then you're in for a ride. Fortunately, a low of folks have gone before you here, so help is available.

Serper3

iTrader: (3)

Wow thanks alot for your help.
can u link to instructions for how to mod the ms for the 99?

so if i wire the db37 to the factory connector... how will i be able to pull out the MS for inspections? i am kinda confused as to what the connections are like on the MS and stock ecu. the ecu ha the db37 port? and i will get wires coming out of that that i will need to wire in? if i dont need to buy anything else, and they have to be soldered in, how will the come out?
i have soldered some stuff before but i was just messing around. this is totally different because well in the end its crucial that this thing works.
as far as the AC delete.. believe me i tried to just pull it, but my gf will drive me up the wall if its gone...
as far as ordering from diyautotune... i can just order the 3.0PCA board.. i dont need it to be modded for the miata because i am going to be doing this is that right? i am also going to need IATwPiggy $22.25 IAT Sensor, 38NPT-Bung_S $8 Steel Bung for mounting IAT sensor, TuneCable $5.50 6' DB9 tuning cable USB-2920 $20.
also whats the JimStim-C $95 Assembled JimStim diagnostic board? is this to test the ms that i am building to see if its working and built right? is this really necessary?
also, if i build the MS in parallel, would that be easier? if i do it in parallel, would i not need to build the MS, could i just get a MS with miata mods and only do the wiring to an adapter to fit to the stock ecu(so that it can be unpluggable)?
again thanks alot Joe i appreaciate your help VERY much!!

jwx

When doing it Joe's way, these are the instructions you want to use, http://www.msextra.com/ms2extra/MS2-Extra_Miata.htm and here is the link to the full manual, http://www.msextra.com/ms2extra/

The JimStim is a handy tool for a number of different things. One of which being testing the board while you are building it; if you buy an assembled MS2, you can use it to check your mods. You can also use it as a troubleshooting tool when you are wiring up the car, and down the road, should something happen and everything stops working.

Serper3

iTrader: (3)

thanks for the links. i am honostly doubting my ability to be able to follow those directions in an adequate manner to have this work. i am still wondering if i can get a MS with miata mods from diyautotune and run it parallel with stock ecu so that i wouldnt have to do any internal modifiying of the MS.
sorry for being such a noob with this stuff though. its really kinda confusing for me to understand how this all will work, plus what will and what wont work etc... i do appreciate the help greatly!

Joe Perez

iTrader: (8)

Whether you are standalone or parallel, the MS needs to be modified internally.


Build an adapter cable with a DB-37 on one end, and a factory-style ECU connector on the other. This is described in the very first thread in the SUPER Important Megasquirt Threads sticky. In fact, there is even a picture:



You really need to read all the threads in that sticky from top to bottom.


Pictures of GF or ban. I'm not kidding around.


If you feel comfortable doing the mods yourself, then sure. Otherwise you have have DIY do the mods for you- they're pretty familiar with Miatas.


Yes. It generates inputs to send to the MS, and then monitors the outputs that the MS is producing.

AbeFM originally did his '99 in parallel, then converted to standalone. His opionion was that going parallel was much more difficult than running standalone.


Huh?

AbeFM

iTrader: (3)

There is a "wire bundle", 23", for like $12 that's worth getting. But, instead, ask them for maybe 36", it'll scale linearly with length. I mounted mine by bungee cording it to the AC condensor box, and I loved it there. Out of the way, easy to get to, etc.

As to the cable, it'll look like this, no permenant soldering to anything:

Guess which one is the nice, clean, stand alone version and which is the PITA parallel install, wires going everywhere thing?

I'll get a pic for you later, of where I mounted it, I can't find one. But the nice thing is, with the OEM ECU out, basically I have nothing in the footwell, it's all clear by the driver's feet.

You'll want to hit radioshack and buy an opamp and some resistors for your inputs, but basically your list is fine. You will need a connector for the other end to make your boomslang.

Because you always forget to bribe me with my own beer. Bring it tomorrow?

Yeah, if we can do it, anyone can.


with a boomslang, you just unplug the adapter cable from your OEM harness (it goes to the MS) and plug it into your OEM ecu. That's it. Drive it a bit.

This JimStim is not only invaluable (make sure to get the two-white-dot version, it's the only one compatible with the miata, I think that's what the "c" means, but ask DIY before buying it) as a tuning and testing aid, it's also a GREAT place to warm up your soldering skills. Even with a lot of soldering in my past, I was greatful for the chance to pracitce building the jimstim.

In short, DON'T get the prebuilt one. Save the money, put it together yourself, and it'll build your confidence for the main build. You'll be glad you did, and you'll better understand how it all works.

NO NO NO don't do it in parallel. It costs more money, takes more time, and works much worse. The only reason to do a parallel install is for emissions testing, but it's really hard, it's a much bigger project than just throwing a stand alone together.

I've got tons of pics and small hints at:
http://abefm.smugmug.com/MegaSquirt%20Stuff

And a few more at:
http://abefm.smugmug.com/Miata/143130

Joe Perez

iTrader: (8)

I thought your A/C box was on the floor of the garage?

Your beer? Your bottles, maybe.

I still haven't touched the growler (I wasn't even expecting you to bring it last time) so we can certainly break into that.

AbeFM

iTrader: (3)

No, it's up in my rafters. Anyone want to buy 90% of an AC system (missing one hose, needs some fin straightening on the condensor)

The point remains it was the best spot I could even ask for for mounting the MS. Super easy to reach, short wire and hose runs. I guess maybe under the hood would be better, but not much!

Yes! That would be awesome, bring the growler! I can't wait for tomorrow, now.

Has it been in the fridge? The bottles I left out continued to carbonate, I think - tasted better before.

Joe Perez

iTrader: (8)

Well, bring it down, Tomorrow I shall probe your A/C Amplifier, and we can put this whole matter to rest.
Yes, it's been in the fridge the whole time.

So you're saying the bottles left warm have gone bad? Or did they just overcarbonate even more? (We definitely need to take it easy on the priming sugar next time...)

Serper3

iTrader: (3)

i swear i have read the MS stickies like 25 times in the last 3 months. it does wonders though, when u say this is a ( ). and post a picture lol. i am understanding more and more how this is supposed to work and it is seeming more attainable for me to do. sorry with the whole parallel thing, i was under the impression parallel might be easier.
the only thing left for me to ask, and i am sorry about this in advance because this is holding hand status.. but can i run a purchase list by u guys? pretty please?
MS2 CPU 3.0 PCA (unassembled)
JimStim-c two-white-dot version (unassembled)
StimPower
"wire bundle", 23" (this is supposed to come with DB37 adapter on one end?)
IATwPiggy $22.25 IAT Sensor (this is the only other sensor i need?)
38NPT-Bung_S $8 Steel Bung for mounting IAT sensor
TuneCable $5.50 6' DB9 tuning cable
USB-2920 $20
What else am i going to need to order, or buy locally to make all the mods to the JimStim and to the MS?
where would i get the yellow connector that i will be wiring up from the db37?
what is an opamp and what kind of resistors/how many resistors will i need?
anything else i need to be able to have the ms power the ac?
Again guys you are the best and i am soo thankfull! hopefully i can order all the stuff tomorrow...
thanks!

Matt Cramer

C's for complete, and there's now a "three white dot" version of the JimStim out there that also works with the Miata.

The wire bundle doesn't have a DB37 on one end; the pictures in this thread show one where somebody soldered the DB37 / plastic backshell that comes with an MS kit to the large wire bundle. The MSPiggy is a DB37 crimp type connector with a metal backshell on 18" of the same wire.

Joe Perez

iTrader: (8)

First off, I'm giving you 24 hours to produce pictures of the aforementioned GF, or the banning will begin.

Now, it sounds like you've got the basics taken care of for a "base" MS build. There are quite a lot of various bits under the "Mod Kits" section you might look into. At a minimum, if you don't have a Fry's, RadioShack, etc nearby, or access to a bunch of component parts at your lab, you'll want to pick up the IAC modkit, a couple of the Relay Control modkits, and maybe a couple of the Pullup Resistor modkits. Each of these is basically just a little bag of parts that you can use to do mods with.

If you ever plan on doing EBC, now's a good time for that. Also, I'd personally recommend buying a second 250 MAP sensor and doing constant baro- even if you don't plan to drive to the top of Everest, it'll guarantee no false baro readings if you run into processor resets at any point.

Buy an old ECU and rip the connector out of it. Or try the supplier in Brainey's FAQ.


Uhm... Yeah. Abe, you sure we want to be pushing him to build this?

Serper3

iTrader: (3)

lol i dont really have any pics of the gf.

i do have frys and radio shack around here..
i am honostly not that bad with directions i think if the instructions are well explained, it will be ok...
thanks for the help!

Joe Perez

iTrader: (8)

23 hours and counting.

Ok, what we're talking about with the comparator circuit is something Abe came up with to replace the "standard" trigger input circuits that everyone else uses. Apparently he was having trouble with missed triggers using the normal circuit, so he reverse-engineered the OEM NB circuit and came up with a comparator-based circuit, which I've drawn as follows:


Does that look like something you can build and test?

pschmidt

iTrader: (19)

You guys build the circuits in the proto area, correct?

Serper 3: Radio Shack has a drawer labelled "Opamps" They have the Lm393 for ~&1.97 Good luck on the resistors though, Rat shack doesn't have ****

AbeFM

iTrader: (3)

Time marches on!

Matt, you guys do sell the wire bundle by the foot, right? So 36" = 1.5xcost of 24"? 23" meant I had to pull all my wires pretty snug. Frankly it works, but with 30" I'd have been a lot happier - this is just specific to where I mounted my MS, but I think it's a really good spot all said and done.

Yeah, I've noticed every (first) megasquirt is built by some clueless, totally lost guy, and every megasquirt that was built by it's owner is owned by a guy who knows them inside and out. Or at least reasonably. :-)

No worries, asking questions FTW. Matt, I thought the USB-2920 has some issues with the MS-II? Or am I misremembering? Maybe I am thinking of something else, but check with him before you get it. Fry's has one I like, there's a few others (check out the MS-x development forums for a list of known good and known bad USB dongles is Matt doens't ok that one. If he does - get it, even if it's $3 extra, it's totally worth it to have something headache free - and he does a nice job.)

Yes, you'll want some mod kits, a couple extra diodes... There's things like VICS on and cooling fans you'll be wanting to run, all entirely doable, but damned annoying if you don't have the parts. And it's better to get the kits than to spent three days making 40 trips to radioshack like I did. Unless yours has a cute girl behind the counter like mine does. :-)


In my pics, you can see the way I mounted mine. I actually still like this. If you were an electronics wiz, I'd suggest trying to recycle the OEM 'boost' sensor which monitors gas tank vacuum... But probably best not to. :-) You could mount the caps in other places on the board, but this worked for me:


Uhm... yes. :-) There's already op-amps in the normal build, it's just pins after all.


and

Should get you everything you want. Go to radioshack, get their 'dual bi-fet op-amp' (could be 'operational amplifier', but who does logic with them anymore?)

Now, I know not everyone is blessed with a digital camera, a camera phone, a friend with a camera phone, or a kinko's where you can politely tell the girlfriend to nose onto the scanner and wait to be digitized, but you could always go to the supermarket, buy one of those disposable, underwater cameras, snap a picture, bring the camera to the one-hour-development photo booth, go to said radioshack, buy a scanner, scan in your picture, and upload it all within 24 hours.

Or, if you DO have access to a camera, take a picture. And if you can't see the girlfriend on 24 hours' notice, how is it she tells you to put AC in your car?


You're welcome!

Joe Perez

iTrader: (8)

Eleven hours and counting...