Megasquirting my stock '99 NB
 

Hi guys,

I'm planning to install a turbo, probably a BEGI-S, in my '99 10AE. Before I do that, I need to rebuild the bottom end (leaks around the rings).

Before I do any of that, I'd like to get the Megasquirt installed and get some experience tuning it. I'll be doing a parallel install, to allow the stock ECU to control the alternator, AC, and basic OBD-II stuff for emissions testing. I may go full standalone sometime in the future, but I want to start here and learn how to tune the device.

I've been following Braineac's Post, but I'd like to get my Megasquirt pre-built so I don't have to learn assemble boards. I'll save that for another project, if possible.

Is thispre-assembled MS-1 pcb2.2 the right starting point?

To build my boomslang-style harness, I need a Megasquirt Tuning Cable (DB9 straight-through), a 18" Megasquirt pigtail harness, and a bunch of 64, 26, and 22 pin connectors. Does anyone sell the wiring harness pre-assembled for a parallel install in the NB?

I've also seen mod-kits described, but I'm not sure which ones are necessary for an NB parallel install. Do I (or will I, once I build the turbo) want the IAT, boost control, or relay fan control mods? I understand I don't need the IAC if I am running in parallel.

Are you planning to put the '97 or earlier CAS in place? Right now the only ways to get MS1/Extra to run on an NB are to install the earlier CAS or a missing tooth crank trigger.

I strongly council against purchasing the R2.2 pca. The R3.0 board is a much nicer design, and the cost difference is trivial.

If you were to use the MS-II CPU as opposed to the MS-I, you could use the stock NB cam and crank sensors and not have to deal with an NA CAS.

One option for your harness would be to purchase a "factory harness extension" from Boomslang. This product is exactly what the name implies- just a plain ole' male-to-female extension that goes between the factory ECU and the factory wiring. The idea is that it gives you a convenient place to do all your cutting and splicing, making the MS essentially a plug-n-play device. So on this extension, you'd cut the injector and ignition lines and bring the car-side of them over to the MS, tap into power, ground and the sensors, etc. The pigtail harness could be used for this purpose, though honestly it's not that hard to solder some wires into a DB37.

you can buy the same thing from DIYautotune prebuilt. they can even do the mods for you. then its a matter of buying/building a harness.

Yes, that's the plan if I go with the MS1 I mentioned above.

I didn't realize this was possible - all the posts I've read here and on m.net talk about using the MS-I and NA CAS.

I'm not too worried about the trivial cost differences - I just don't want to be too close to the cutting edge. I travel all the time for work, so my quality time with the car is limited to Saturday & Sunday. I only want to spend part of that time under the hood (or upside down with my head under the dash) ;)

How many folks have had success with a parallel install on an NB using the R3.0 board?

Is that in addition to the preassembled kit I mentioned above? Or would I be asking them for a "special order" with mods already done?

Do I need the same mods for an R2.2 or an R3.0 board? MS-I CPU vs MS-II CPU?

you want the v3.0 board assembled kit. MS-I, with miata mods.

You can email us at websales@diyautotune.com to set up orders for special order ECUs.

The only MS2 on NB stock sensors I've seen personally is AbeFMs, but then I've only seen two NB installs in total, and one of them we just did yesterday. Abe originally ran parallel, but finally manned up and went full standalone.

Incidentally, you NB guys have the most frakked up ECU location I have ever seen. :D My back is killing me today.


Seems like a strong argument in favor of using an MS-2, not having to install additional sensors, and building an inline PNP harness. On Saturday morning you can stick the new harness in place between the ECU and the car, play with it, and come Sunday afternoon if you're not happy you can pull the harness out and be back to stock for the week.

And of course, using an extension harness means that you can do all the wiring sitting comfortably at your workbench, rather than standing on your head under the dash.

Probably more than have with the R2.2, given that very few people are buying the 2.2 anymore. That board is essentially obsolete, and I have utterly no idea why they are still being sold as new. Functionally, the two are quite similar (and in terms of their I/O pinning and such they're identical except for the additional I/O on 3.0 which 2.2 doesn't have), mostly the 3.0 just has more space to work in, fewer hacks required for operation, better power and ground distribution, etc.

you know, ive been trying to follow along with abe's read up because im planning to switch over to MSII for stock sensors. The NA CAS apparently is a POS, and i get misfires and OBD check lights like no tomorrow.

where would i find the correct schematics for the stock sensors? thanks guys.

Don't Worry. Your Posture will straighten out with that nice ergonomic Nardi Torino :D
Thanks so much, again. That was totally AWESOME of you guys to help me as much as you did and I dont think I could ever thank you enough to repay what an invaluable service you guys performed for me. and BTW I ordered the LC-1 With a red Gauge. I just figured, 'do as the romans do' I'll also be ordering a tablet and fabbing up a mount similar to yours.

Maharashii, Listen to this guy. Him and AbeFM are the fuckin MAN(s)
I will also Man up to full standalone as soon as I get it to a comfortably tuned level.

In the wiring diagrams of the Mazda factory service manual. http://www.madracki.com/miata/wiring.html

But here:

http://img31.picoodle.com/img/img31/...0m_c68fa73.gif

so what da issue been?

FYI I will probably be selling my '99 BEGI-S intake pipes very soon. They are in excellent condition, and already tapped for the AIT sensor. You can delete the pipes from the S kit and save some money.

OK thread jack over

The major problem was that he was trying to do a COP conversion at the same time as a MS conversion. The COPs were ones that I'd not seen previously, and they were either damaged or mis-wired, because any time you plugged one in (even with the MS out of the car) the 15A engine fuse immediately popped. We yanked them out and put the stock coils back on, and that fixed that.

I went through the ECU wiring pretty carefully (or at least, as carefully as a person can while standing on his head for three hours under the baking sun in a flat black car on a 100° day, watching other people drink his beer) and noticed one other abnormality. He used the piece of shielded coaxial wire that came with the MS pigtail for the CKP input as per your writeup, with the center conductor at DB-37 pin 24 and the shield at pin 2.

On the other end of that cable however, the shield was spliced into a wire of the factory ECU harness. My memory is hazy, but I believe it was a green/orange wire which we determined to be pin 2K- goes to the instrument cluster and the diag connector. I'm pretty sure it's the tach wire. So that wire was being grounded through the MS. Pulled it.

Anyway, the car starts and runs, though it's quite rough. Without a wideband it's hard to know where we are, and by the time we got to that point we were all pretty tired and just happy to see it running at all. For some reason, even though the O2 wire appeared to be connected I didn't seem to be getting a reading from it. Ignored that since a wideband is in the plan.

Also, I seem to recall that the MAP read a bit high- like 40-50kPa at what passed for idle. TeamPlur- if you're reading this, check very thoroughly for vacuum leaks on that line, and also tell me where on the manifold it connects, I forgot to check.

While trying to figure this out, Abe pointed out that we had no idea what the stock ECU was trying to do with the IAC valve- aargh! One of the frustrations of a parallel install.

parallel installs are badass.

If I wanted to do a parallel install on a '99, using the stock sensors, which parts would I need to order from DIY? I'm tempted to give this a shot. I'd use a Boomslang harness to simplify things.

Thanks

must read my FAQ you shall.

I read the one located here:

https://www.miataturbo.net/forum/showthread.php?t=13676

If I want to run MS-II, I'll just need to substitute This
Rather than This. Correct?

basically. modding it for inputs will be different, and im sure abe can help out...

Pretty much. You should read the MS-II specific documentation here: http://www.megamanual.com/ms2/index.htm with particular attention to the "Installation" section- there is one jumper you need to add to the main board that MS-I does not require. And as Briney said, some of the "advanced" I/O gets pinned out differently.

The "big deal" with the MS-II in this regard isn't so much any additional capability or feature related to the extra processing power so much as the fact that the MS-II config software happens to natively support the NB's rather unusual crank wheel and cam setup, whereas there doesn't seem to be a way to configure the MS-I's software to deal with those inputs.

Sweet. Consider me interested. PM me when you're closer to doing so, and I'll do the same before I start ordering BEGI-S parts.

For my parallel install, looks like I have to choose:

1. MS-I on PCB v3.0 with NA CAS (a la Braineac)
2. MS-II on PCB v3.0 with stock NB CAS (a la AbeFM)

The first option has been done by quite a few on this board, while the last one seems to have only been done by Abe, but should be an easier install since I don't have to funk with the CAS, but then I end up getting awfully close to the leading edge. In other words, if the shit hits the fan, I'll have to drive to San Diego and drink Joe's beer while he fixes it for me ;)

Would my decision on which way to go be influenced at all by whether or not I bolted my '99 head to a '94-97 block or a '99-00 block? I'm still shopping for a 1.8L short block, and I'm not sure what I will end up with just yet.

No, no, no... You drive to San Diego and drink Abe's beer, while Joe laughs.

It's hard for me to know what factors would influence your decision. Personally, I'd be strongly influenced by the offer of a three-way with Tricia Helfer and Grace Park, but if bolting engine parts together is your thing...

Seriously, it doesn't matter one bit which block you are running so long as the head is an NB part and the block has the crankwheel sensor mounting hole (I don't know if the '94-'95 blocks do.) The sensors and factory harness are what drive this decision. Either you choose to use the stock NB stuff, or you choose to install a CAS, run additional wiring, and live with spark jitter. I do know that the '96-'97 crank sensor and the NB crank sensor are mechanically different, but electrically they should be the same. (It's possible that their alignment is different, so you'd probably want to stock with the NB sensor)

I don't think Abe's the only one. The whole reason the MS-II is "special" insofar as the NB is concerned is that it comes pre-loaded with a decoder for the NB crank and cam sensors- you literally just select "NB" from a drop-down menu and the decoder is ready to go. Therefore I have to assume that others have gone before. (Granted, Abe seems to have been one of the principle driving forces behind getting James & Phil to make this change to the software)

wow no shit! Thats great if the only needed choice is to just select the NB from a drop-down menu. I havent checked the actual setup of trying see the megatune settings for MSII.

what my original question was implying was if there is a special schematics that is required to make the stock sensors work properly (i.e. external box with a bunch of resistors and caps or what not)

so all in all, all you need to do now is just hook up the wires from the stock cam sensor and crank sensor to the inputs on the stock NB? and mod the MSII accordingly?

I only looked into it recently myself. Despite their common heritage, the software configuration for MS1 and MS2 differs greatly in many ways.

With the MS1, for example, in order to change your CLT and IAT sensor values, you must re-flash the whole firmware, which requires you to disconnect the ignition system, compile code (well, not compile exactly since it's ML to begin with) then re-load your MSQ, basically a lot of fucking around. With MS2, you just enter a couple of numbers into a screen.

Likewise, the MS2 seems to come with a lot of common wheel setups already defined in a drop-down menu. With MS1 you have to calculate and then manually enter the tooth configs for your wheel. It's not hard and it's a one-time deal, but it's just different.

On the other hand, there are some things with MS1 that are easier. As far as I know, MS2 does not have a working closed-loop idle, so in a standalone configuration you have to fiddle around with duty cycles and such. With MS1, you just enter a couple of target RPM values and some DC limits, and it auto-seeks the idle you've told it to.

The input hardware is the same for MS1 and MS2. Either way you've got to build a second trigger input and, if necessary, a filter circuit to clean up the primary. For most people, this does not seem to require a lot of complexity, just a couple of resistors and a cap. In my case, dealing with my CAS (which I believe to have simply been marginal) was a living nightmare- hence my crankwheel project.

Arga was the first MS2 parallel install on an NB. Pretty sure he is the one that got the guys to write up the beta code to use the NB sensors.
I'm running MSI with a 94-97 CAS and it works great. The install is easy and i don't have issues with it running correctly. Grounding is very important and so is the rest of your wiring.

It might be more accurate to use the NB sensors but considering there are only two people running parallel MS2 on an NB i believe and one of them is now going standalone I would suggest you go MSI V3.0 is parallel.

I truthfully think MSI with a crank trigger like Joes is the way to go for sure unless a circuit can be built to use the NB sensors.

Or there is always Joes idea of grinding the odd spaced teeth off the NB wheel and using it as a two tooth wheel.

I was MSII parallel on my 99 for a few months. I had some problems with my MS and wiring harness and have decided to go standalone now for simplicity. I will be using a Ford EDIS 4 ignition system with my MS2 for ignition though. It's simple and well engineered, but would require you to fabricate the parts to mount the trigger wheel and sensor. Should be a bit better than the stock stuff, simpler, and more accurate. Plus I won't have to deal with hooking and unhooking my coils anymore.

I will say though you can run MS2 on stock sensors, I did it. You need two simple circuits in the MS for ignition inputs. They are really simple. PM Arga and ask him to send you the diagrams for them. They are the same for cam and crank sensors. Do that, select NB, and it works.

what's "spark jitter"? I searched but didn't find much.

Jitter, in general, is the tendency of an electrical signal to exhibit small and usually random deviations from "normal" in the temporal domain.

Translated into English, that means that if you set the spark to 10°BTDC and rev up the engine, it might be jumping around between 7° and 13° (or more).

It tends to happen at higher RPM, and its caused by the fact that the CAS is driven by the timing belt. That belt, by design, has a small amount of slack in it, and thus the CAS is not perfectly locked to the crank- it wanders around a bit.

By moving to a crankwheel, this variable is eliminated.

Hey I understand the phenomenon here, but is the error really that high? On the order of +/- 3 degs?

Yes. While I was testing an ignition input circuit, I locked my timing at 10° and slowly revved the engine from idle to about 6k while observing the timing mark. I was actually looking for drift (due to input latency) but saw an amazing amount of jitter as well.

Before anyone asks, my timing belt is about 3 years old, has ~15k miles on it, and was properly tensioned.

Ahh, this is becoming clearer now. I think I was partly confused because people seem to use CAS interchangeably to refer to the crank sensor or the cam sensor. When I hear CAS, I am thinking of the NA optical cam sensor. Is that right?

Are these statements correct?

• NA 1.8L has an optical CAS that can lead to jitter
• NB 1.8L has a magnetic crankwheel sensor that is more accurate
• MS-I uses the optical CAS for timing input
• MS-II uses the magnetic crankwheel for timing input

In my case, as I'm looking for a block, I can use the following combinations (no matter what I will use my '99 head):

1. Stock ECU with NA block and NA optical CAS
2. MS-I with NA block and NA optical CAS
3. MS-I with NB block and NA optical CAS
4. MS-II with NA block and NB magnetic crank wheel (need to verify compatibility with block)
5. MS-II with NB block and NB magnetic crank wheel

Questions:

1. Does the NB have any sort of cam sensor, or just the crankwheel sensor?
2. Does the NA have any sort of crankwheel sensor, or just the optical CAS?

I'm trying to decide if I will swap the block and get it sorted out with the stock ECU, or Megasquirt the car now and swap in whatever block I find in the future.

Wow, OK thanks for the info.

Yes. Usually, CAS refers to the sensor which plugs into the back of the camshaft on the NA, is either optical or hall-effect, and provides two discrete open-collector outputs: CMP (one pulse per crank rev) and CKP (two pulses per crank rev, aka 1 pulse per ignition event)

I'm not sure if there is a common convention for describing the two sensors (crank and cam) on the NB, or for distinguishing the crank sensor on the late NA from the CAS.

Understand that ALL miatas from '89-'05 have two trigger signals, one which gives one pulse per ignition event (two pulses per crank rev) and the other which gives one pulse per crank rev. The locations of these sensors has moved around over the years, as follows:


All NAs use a camshaft-driven CAS, be it optical or hall, for the primary trigger input and the TDC input. This is prone to jitter due to the loose coupling of the cams to the crank. This CAS provides both the crank reference and the cam reference.

Starting in '96, NAs were equipped with a crankwheel with four oddly-spaced teeth, for the sole purpose of OBD-II misfire detection. They still have the same two-channel CAS as the earlier cars, and with the stock ECU, they use it for the primary triggers. The crankwheel is basically the same as the one fitted to NBs, although the sensor is physically different. (the mounting point changed)

Starting in '99, the crankwheel was used as the primary trigger input, the CAS was eliminated, and a simpler, single-channel cam sensor was implemented to provide the "TDC" signal. Note that jitter in the cam reference is not critical, as this signal is used only to give the ECU a reference as to which crank pulse is which.

MS-I can use any of the following for timing input:
1- Both channels (CMP and CKP) of the stock NA CAS. This scheme requires adding a CAS to NBs, and provides low accuracy.
2- The crankwheel sensor (with two teeth cut off the wheel) of the '96+, and the CMP output of the NA CAS. This scheme requires adding a CAS to NBs, and is not compatible with parallel operation on any car since it requires cutting two teeth off the crank wheel.
3- (theoretical) the stock crankwheel of the NB (with two teeth cut off) plus the stock camwheel of the NB (with the dobuletooth cut down to a single tooth.)
4- A single, crank-mounted wheel such as a 36-1, with a dedicated VR sensor. This scheme requires mounting a custom timing wheel.

MS-II can do all of the above, plus:
5- The stock crankwheel and camwheel of the NB, without physical modification to either.

Basically, what it boils down to is that the MS-1 requires all teeth to be evenly spaced, while the MS-2 does not.


1- Yes. It's near the front of the intake cam. It gives a very strange signal- one pulse at #1 TDC, and then two quick pulses 360 crank degrees later at #4 TDC. This is why it's unusable with MS-I, the software to deal with the single-double-single-double doesn't exist.
2- Yes, starting in '96.

Here is some further info on the NB wheels: http://www.msextra.com/ms2extra/MS2-Extra_Miata.htm I'm not sure why it says '99-'00 only, it's possible that the wheels changed in '01. I only have parts catalogs and docs going up to '99.

Thanks for all the info. This makes much more sense now.

So how much trouble does that jitter cause? I see a lot of references to folks using the NA CAS with an MS-I on an NB, but this is the first I've read about jitter. +/- 3 degrees sounds like a lot.

My power goals are pretty moderate so I don't imagine I'll be living on the edge for tuning. Even if I get the urge to go higher than 180-200rwhp, I probably wouldn't do it. This is my dd and I have to be able to start from a stoplight on cold, wet, steep Seattle hills without looking like a wheel-spinning idiot.

Even if you tune your car for 20 psi on a T04E you won't be making that HP off idle when taking off up a hill. I only spin my tires if i want to.

I dunno - I'm skeptical. On a bad day (stopped on a really steep hill, with some asshole right on my bumper, on a cold wet day) I have a hard time launching with stock power. I suspect even a moderate increase in torque is going to be a challenge, but I digress ...

If I go with an MS-I and a parallel install, I do I need the IAT mod or can I just use the stock AFM/MAF?

It would, except that a reasonably-sized turbo isn't going to be adding any torque at that point. Not enough RPM, not enough throttle, not enough flow. Now, if you floor it while cruising along in 3'rd on that same cold, rainy day, then yes, your car is going to start sliding sideways. ;)

Digressing a bit, but I find it helpful (when starting off uphill) to hold the e-brake up with my right hand while modulating the clutch and throttle, letting the brake out slowly as the clutch engages. Much easier to do gently than heel-toe.

In a turbocharged car, having the open-element GM IAT sensor will be beneficial beyond mere AFM/MAF removal, as it will allow to to read actual intake temp after the turbo and I/C.

+1, works great.

i just read through the manual, still trying to comprehend those circuits. seems to be more complicated than i expected? or is it shown in excess on where exactly the signal is going through?

EDIT: examining more, it seems like some circuits will be needed to changed out of the original holes on the PCB board? for the CAM sensor, i understand that the circuit shown requires to be built using the listen components. the crank sensors input has my head spinning

So assuming MS-I for now ... this is the parts list I'm looking at:

• MS1357-C Assembled Megasquirt-I with V3.57 PCB
• MOD_13571GDSM Preconfigured 4G63 / Miata ignition output
• JimStim-C Assembled JimStim diagnostic board
• MSPiggy 18" wiring harness pigtail
• IATwPiggy IAT Sensor (if not sharing temp signals with the MAF)
• 38NPT-Bung_S Steel Bung for mounting IAT sensor (Alumimum or stainless also available)
• TuneCable 6' DB9 tuning cable (unless I have one in my junk pile)

In addition, I need the boomslang extension, which I can splice into with the MS Piggy. I don't quite have all those details straight, but I'll figure that out later.

Now my question is, considering that I'm running stock, how important would it be for me to have a wideband? Can I tune via default maps and educated guesses and then wait on the wideband until I start making engine mods (turbo!)? My goal is to have no CELs. I want to be able to drive the car right up to the emissions testing center and pass the OBD-II test without any issues.

What part of 2 identical simple circuits did you not understand? Reread my post.

Trying to comprehend what you wrote is making my head hurt. Seriously, is English your primary language?


Any details on what, exactly MOD_13571GDSM consists of? I ask because, given that you're doing a parallel install, some other modification might still be necessary. For that reason, it might be preferable to go with the 3.0 PCA as opposed to the 3.57.

Since you have an NB, I would suggest that you at least consider the MS-II CPU. It'll pay for itself in the savings you realize from not having to procure and install an NA CAS and associated wiring.

I wouldn't even dream of tuning a standalone ECU without one, even on an otherwise stock vehicle, but that's just me.

Finals left me brain dead. I haven't been able to talk straight for the past week :hustler:

Anyway, electrical stuff isn't my forte, so I tend to ask more about it before I tackle anything regarding electronics. The last thing I would wanna do is fuck something before i used the wrong capacitor or I didn't read the schematics for the circuits right (i.e. where things connect and what to follow)

The MOD_13571GDSM code is for Miata / DSM ignition mods with the pull-ups on the ignition inputs and 5 volt ignition outputs. Not quite the same mod version we use on the MSPNP but close.

We'd need to do a bit more testing in-house before we offered any MS-II products set up in our shop for the '99 and later Miata. We stick to mods we've either tested in-house and can guarantee they'll work or a couple mods that have had very extensive testing and we have a good way of bench testing.

I have been following this thread with interest, as I am an NB'er. I have both a 95 and a 96 CAS. It appears that the 96 will offer some benefit over the 95 CAS? I should add, I know the 95 is a 26K mile CAS, whereas, I can only assume the 96 has 150K on it. Are miles an issue?

I agree with you completely ... but as Matt said they don't have one built yet, and as much as I love a good DIY project, I don't think I have the time to learn to build my own MS-II and do it right.

I've been reading the threads of all the folks who are much more experienced than I when it comes to engine management and building circuits, and I suspect that it would take me a long time to get it built (I travel all week for work, and only have Fri afternoon - Sun evening at home. I can only devote so much time to car projects). By then DIY might just have one for sale.

Now, if Arga or AbeFM would like to build it and come to Seattle to help me install / troubleshoot a parallel install ...

Otherwise, I'm thinking an MS-I is going to be more manageable for me, even if I do have to do some extra wiring.

Cool. I'd not heard of this particular mod package- the OP didn't mention the inputs and I couldn't find a schematic (or even a description) on the website.

What mods do you typically do to the boards?

The reason I ask is that, insofar as I can tell, the hardware side of it would nearly identical for both MS1 and MS2 (and for that matter, NA vs. NB), at least insofar as the "basic" and "intermediate" mods are concerned. The second trigger input is the only one I can think of off-hand that changes- JS10 vs. JS8. Even EBC, Constant Baro, Launch Control and TachOut can use the same pins on MS2 as on MS1. Knock would be a different pin, as would table switching. Same circuit, just a different CPU pin. (and truthfully, I don't expect you guys to be enabling all those features, as getting them to work is probably outside the scope of your average PNP customer's comfort range)

I do understand needing to test the product prior to shipping however. I wonder if this might be a case where a collaborative effort would be in order? IOW- mod a 3.57 PCA to your "standard" Miata spec, then have a third party document the process of getting it reworked and operating to MS-II specs. I don't think it would be all that tricky, particularly if said third party also built and documented the Boomslang harness prior to delivering the complete assembly to the end-user. Said third party might even be able to find someone with an unmolested '99-'00 in the San Diego or LA area willing to be a guinea pig, in exchange for receiving unit #2.


In terms of their design, the '95 and '96 CASs are absolutely identical. The same part. BPE8-18-230. Mazda did not change the cam sensor until '99, even though they added a crank sensor in '96. All Miatas '94 to '97 got the same cam sensor. I would go with the lower-mileage unit.

I was confused and misread crank sensor for cam sensor earlier in the thread. Thanks for clearing that up.

You should definitely get one IMO. It pays for itself pretty quickly by taking most of the guesswork out of the tuning; it saves a lot of time and frustration. A WBO2 coupled with data logging (megatune) and megalogviewer is a great tuning tool. I love mine.

You can damage a stock motor with an overly lean mixture. The turbo makes things riskier of course, but that does not mean you are safe with no turbo. I guess you could just load up the very conservative PNP map and be OK, but, you are really going to want one eventually (with the turbo), so why not play it safe now? Plus even NA (no turbo) you can get it running better versus the PNP map, and it gives you a chance to get your tuning skills in shape before the turbo goes in.

In short, play it smart, get one.

Good point. The biggest reason I'm planning to install the MS now is so I can learn to tune it before I get the turbo. Wideband it is.

Mod codes are not listed on our website - when special ordering something, we usually set up the order by email and have a chance to explain to the buyer what they are.

The thing with the MS2/Extra mods is that we'd like a bit more experience with what could potentially go wrong with the mods before we ship a unit. If there are any hidden "gotchas" to either the mods or the code, we don't want to find out from a frustrated customer first if it can be avoided.

For example, not long after the MS2/Extra direct coil control mods came out, a bunch of controversy erupted over whether VB921s needed 330 ohm or 750 ohm resistors, with people arguing over issues with the larger resistors not starting in cold weather and noise issues. If we'd picked the wrong version of the mod when it first came out, we'd have had quite a few recalls on our assembled units. So we waited a bit, and did some testing of our own. Those Bosch BIP373s we sell, we did all kinds of crazy things to make sure we knew what could go wrong - trying to fry them with too much current, sticking them in the freezer, virtually every torture test we could imagine.

I've not been keeping up with my beloved MiataTurbo.net. Sorry folks.

The biggest troubles I had with the whole standalone were 1) not enough electrical damping on the VICS valve. Needed a good diode, might need more than I gave it. It was masked by other problems. 2) The input circuits. As mentioned elsewhere, I just copied the OEM circuit. I figure it's reliable enough for mazda, it must be reasonable. So far I've had no reason to doubt it.

Honestly, in a no-holds-barred build, I'd do a multi-toothed wheel, though I'm not sure about decoding the VR in the MS verses on the sensor. But it seems to work, so I can't really argue with that. The cam sensor is used so poorly by the MS I don't know why they bother. In fact, there was a bug in the code where it ALWAYS thought it was on cylce one, never two, and it didn't change anything, except the motor starts slower.

As fas as the inputs go, it's really very simply, a handful of resistors, one cap, and one 8 pin chip. That gets you from DB37 to CPU.



Still bitter about it? :-) I'll either bring by the two liter growler, or you come down and get it. :-) Last night we had 4 MS folks in the house - with 5 MS between them. Three mazdas. Pretty good times, though it's shocking how fast that bores the girlfriend. :-)

That's my biggest issue with parallel installs. You're always guessing what's going on.

The MS-II does indeed have closed loop idle. They brush over the details and call it a PID closed loop, when really it's just some weird, poorly written function the takes an input and varies an output (not quite at random), but many people have it set up well enough. But my MS idles so smooth, I've found it much more prudent to just raise the RPM 100, and let the loads come as they may. It's never flinched or misbehaved since the switch.

The crankwheel is the way to go. I only did the stock sensors to prove it could be done.


The wheels on the later car are identical, only the phasing varies with VVT. Unless the angle varies so much as to move the pulses out of the range between the two crank teeth, there's no issue - as you said, it's only used for determiing TDC. As I understand it, you could just put it on any NB miata, but no garuntees. However, if there was an issue, I'm pretty sure just a small phase difference (moving either sensor a few degrees) would solve it.



Lastly, just a bit of advice. If it were me, I'd run a standalone. More of my problems came from either wiring or operational issues trying to get the two computers to work nicely together. If I was concerned for smog, I could put the system together with a well thought out boomslang, and just swap to the OEM ECU (and maybe injectors if applicable) for the tests. Absolutely not worth the headache.

Someday, someday, I'll write a 99+ guide.

:)

I spent a couple hours Friday night with the soldering iron and I have a "functional" MS-II board.

I am about to begin:

"Input Section Construction & Testing

42. Remove the processor from the 40-pin socket - use a thin screwdriver and pry it from the socket, first one end, then the other - place it back on the foam pad it was shipped with. Now, you are going to install all of the input sensor components. "

What I'm having trouble with is:



On a '99, do I want to install this jumper?

Also, about the crank input I want to duplicate for the cam. Could someone explain what I'm doing here? This is where I am really lost. If someone can give me pin by pin instructions (:noob:) I will make it worth your while; beer, MS Parts, etc.

Thanks

We don't use a stepper IAC so you don't need that mod. Can't answer your input mod question, sorry.

Which circuit did you build for the crank input?

The most basic cam input circuit, which most people use, is the one described in DIY's How to Megasquirt your Mazda Miata article. The article is written for an NA, however the electrical characteristics of the sensors on the NB are virtually identical. Alternately, you could follow the instructions in the MS2Extra manual. Their circuit is, in my opinion preferable, since it optoisolates the CPU and is more or less identical to the primary input circuit: http://www.msextra.com/ms2extra/MS2-...tion.htm#2hall

Thanks guys.

I built both inputs for the crank signal like the manual suggests. From Braineaks's DIY it looks like I didn't need both. Is that an issue, or can I just jumper what I need active?

The circuit here:
http://www.msextra.com/ms2extra/MS2-...tion.htm#2hall

I think I understand it. I apologize for being so new to this.

I understand where the resistors go, and what to solder to with JS10 for example. Where I get lost is with the meaning of the numbers next to the right angles in the diagram? Are those the pins for the 4N25 opto isolator? If so, where do I want to build that circuit? Proto area? If so, I think I have it down.

Thanks again.

You built both the VR and the Opto input? No problem. Leave the VR circuit alone and just jumper the opto circuit.

Again, you can make the CMP input circuit simple or complex. If you do it with just the two resistors like everybody else, that's simple. Or you can build the one linked to above, and personally I think it's a better design.

The numbers are indeed the pin numbers on the 4N25.

Are you building standalone or parallel?

While I can see Abe's point on going parallel I don't agree with him 100% once you have control of idle, fuel and spark I don't see how the OEM ECU can effect anything other then the EGR valve.

But, as Abe mentioned I built a boomslang like harness with a couple SPDT switches that allow enabling and disabling the megasquirt. I also have a MS-II built, I used the standard spark outputs and 2N2222A transistors for inputs coupled to TSEL and JS-10. I hope to test the system next weekend.

Here is the circuit for a Parallel install, Arga designed it.

Exactly. YOU don't see it, but the fact is it still happens. Listen to Abe. He knows his shit. I ran MS parallel on my 99. I had too many problems. I'm going standalone now to get rid of all the nonsense and headache.