yertnamreg1218

I've been toying around with the idea of creating a MS adapter board, and I'd like to see if there is any interest here.

The board would have a place to solder the big yellow 64 pin connector a place for a DB37 connector and holes for soldering wire that go to the original ECU. Effectively this would be a breakout board for the ECU and MS signals, and it would also make it much easier to build the harness. The board would be silkscreened with easy to read labels of where all of the signals are. The board would work with both boomslang and standalone setups.

This would simplify the harness building procedure which I found to be the most tedious part of the whole process. Cost will depend upon my production costs, but at the moment I'm guessing boards would cost about $30 a piece.

Let me know what you guys think. I'm currently working on the 1.6L board, but once I get it done the other models should follow shortly.

I'll post some screen shots of the board once I get it done.

Braineack

iTrader: (62)

I can't picture it.

The_Pipefather

iTrader: (5)

He's talking about making something like this:

http://megaefi.com/

Would make MS install a snap really.

yertnamreg1218

Ok so, I'm at a point that I have something to show you guys.
I'm not done with it yet. I think I'm going to add some proto area as well as clean up the silkscreen. Its hard to see whats really going on because I can't get the copper pour to turn off, but I took all the knowledge from the harness portion of the DIY MS thread and put it onto a board which should make everyone life easier when it comes to making the harness.

Joe Perez

iTrader: (8)

Interesting concept.

I'd suggest that you might want to beef up the size of the traces carrying the two INJ signals, those are pretty high current lines. Ditto the IAC valve.

yertnamreg1218

Like I said this is just preliminary. I'm going to beef up several of the traces, bring out and label all the DB37 pins. Hell if I get adventurous, I might add a circuit for the fans and AC (which would practically make a DIY MS a PNP). If I get some of these made would any of you be interested in purchasing one???


Don't forget I also intend to make a couple more of these for the later models.

timk

If you buy an MSPNP you get one of those for free you know!

yertnamreg1218

I'm aware of this...

a) I'm a computer engineer and this is "fun" for me
b) MSPNP's are $600+, not that I don't like DIYautotune, but that seems a little steep. I could easily put a kit together and sell it for under $100. This would effectively bring the price down to $300 ($200 for DIY MS kit $100 for my kit). I don't know about you, but I'm a poor college student and I would much rather pay $300 for a plug and play solution than 600. Also this would not be completely plug and play. Soldering would still be required. This would effectively create a DIY MSPNP for about half the cost.


Not to mention, this is going to help me pay for my turbo this summer.

supersuk

iTrader: (5)

hmmm, sounds interesting. I would like to play guinea pig with this.

alden77

I can't squeal like a pig, but I'd be up to try this out as well. It sounds like a great product, especially if it can be used as a standalone on a car with AC. I'm also going to go with a T3 once I get MS, injectors and Wideband sorted out. See, some of us really do take the advice on this forum to heart.
Best Always
Alden

cjernigan

iTrader: (13)

Sounds like an awesome project to me. If I can help let me know. You'll need different board for 90-93, 94-95, and 96-97 but that's no big deal.
As for NB's unless we can come up with a A/C circuit as well as a alternator circuit (or use Abe's external regulator idea) it will be much more difficult to do this. You could even fab it up so that it could mount to the screw holes on the MS case end plate, possibly using a plastic bottom for some extra strength. Letting it plug directly into the MS.
One easy option for the NBs would be to actually remove the pins from the female connectors that go to the stock ECU for the Fuel injectors and the Ignition coils. Then run the to their own male connector. You could utilize any one of the production boards this way because you could put the pins in any slot you wanted.

Man, what an idea. You do your own screen printing or etching?


EDIT: I like the idea of just pulling the wires out like that and putting them in a new connector so much I think i'm going to do that to my own car. That removes like 55 points of possible failure by removing the boomslang.
It would suck not using the stock ECU grounding anymore but that can be resolved some other way. hmm

Edit 2: Got ahead of myself, went off and forgot about tapping CLT and TPS. Lame. Not a good idea if you want to retain OBD2 compliance like you do with the boomslang. Darn.

Edit 3: That too wouldn't be a big deal. CLT, IAT, and two ground wires could also be pulled from the stock ECU connector, installed the other connector. Then Y off the back of the male connector like we do with the current boomslangs and run those back to the stock ECU.
It sounds messy, but i guarantee the 4 Y'd wires is much cleaner than the 64 wires for a NB boomslang plus the 3 wires for CAS, 1 wire for IAT blah blah blah.

yertnamreg1218

Thanks for all the replies. Sadly no, I don't do my own printing or etching, but I do have access to board mills at my school that I can make prototypes on at a much lower cost.

I'll be starting with the 90-93 because thats what I care about most/own.
I need to do some more research on the NA's AC and Fan sytem, but it shouldn't be too hard to whip something up to take care of that.


As for the NB stuff:
I'm not familiar with it near as much as I am with the NA. I've hear about the alternator, but not in detail. I guarentee you though, if the stock ECU makes it work I can find a way to make it work (or I think I can). Also the AC shouldn't be too bad. My guess is that there is effectively some kind of thermostat circuit that engauges and disengauges the AC clutch based on evaporator temperature. I could whip up something like that with opamps in a heatbeat.

I'm not familar with OBDII, but it seems like there would be a way we could fake that signal. If the stock ECU makes OBDII codes why couldn't we. This might add a microprocessor onto the board, but embedded stuff like that is really my specialty.

Joe Perez

iTrader: (8)

The fan system is dead-easy.

The primary cooling fan relay comes to the ECU at position 1R, a Black / Green wire. If you pull this pin to ground, the primary fan turns on. Note that a relay modkit is required on the MS itself, it can be driven by either JS0 or LED15 (warmup), and there is no standard as to which DB37 pin it comes out on- so this needs to be set in stone beforehand.


A/C requires no work on the part of the MS, just some creativity. When the A/C button is depressed and the interior blower switched on, the climate control panel gives the ECU a closure to ground on position 1Q. Use this closure to drive a relay which provides a closure to ground on position 1J, a Blue / Black wire. The energizes the A/C relay, which turns on the second fan and also powers the magnetic clutch on the compressor. Actually, a relay might not even be necessary- you could probably just loop the two pins.

Although it would sell like hotcakes, the big problem is that this is specifically prohibited by Federal law. Also, the stock ECU, in addition to transmitting the "all clear" message, is theoretically capable of stating its VIN number. I don't know if this feature is currently being exploited, but it's a potential gotcha.

Not sure if you've already got a PCB vendor in mind, but for this kind of thing I use expresspcb.com. They're cheap, they're fast, and the boards are really super high quality- they will do everything from uncoated double-sided (with thru-plated holes) to four-layer with soldermask and silkscreen.

yertnamreg1218

Psshhhh illegal....
Freaking laws, I should be able to do whatever I want with the hardware I own, but I digress.

I'll keep working on the 90-93 board and I'll keep you updated as to my progress. Not sure how much I'll get done in the next week or two. This weekend I'm going to Chicago and we'll next weekend is a holiday...

Joe Perez

iTrader: (8)

As much as it pains me to say it, the laws are there for a reason. While I don't necessarily agree with the decision, I understand the reasoning behind it.

yertnamreg1218

So I was bored and looking at the NB schematics for the charging circuit (page 27 in the 99 wiring diagram PDF). What is the deal with the alternator nonsense. I'm guessing the problem is with this powertrain control module?? If thats not it, I'm not sure how the ECU has anything to do with the power system of the car. Could someone elaborate more on the problem with NB alternator's and MS? I should be able to devise a solution if I know more about what is going on with that.

I've got to go to class :( but I'm going to take a look at the NB A/C later today.

patsmx5

iTrader: (16)

Good idea!

Joe Perez

iTrader: (8)

Basic alternator theory:

The voltage produced by the alternator is a function of the voltage applied to the field coil winding. Applying a higher voltage to the field coil causes the voltage output of the primary windings to increase.

Traditionally, most alternators have either used an internal voltage regulator, or a simple external regulator. The regulator looks at what the "system" voltage is (the voltage actually coming out of the alternator) and either raises or lowers the excitation voltage to adjust it.

Some newer cars use the PCM as the voltage regulator. NBs fall into this category, as do many Toyotas. Apparently, the PCM takes certain other factors, such as temperature, into account in making the determination as to what the alternator voltage should be. See this diagram, taken from the 2000 Miata wiring diagram, section A, page Z-16:



The wire coming out of the middle of the rectifier stack and going to reference (6) is a "sample" of the voltage coming out of one winding of the primary coil going to the PCM. I don't know why they chose this particular location- it's quite possible that the PCM also monitors the "raw" +12 coming into it.

The PCM then outputs a voltage on pin 1T, which comes into this picture at ref (5). That voltage is what drives the field coil, and determines what voltage the alternator will produce. (actually, I question that picture- the way that PNP transistor is shown, it can't possibly do anything. I think it's supposed to be an NPN)


The "problem" is that there is no mechanism on the MS, either hardware or software, to produce a variable output voltage based upon input voltage.

The solution that Abe came up with to run his stock NB alternator on a standalone MS was to locate an external voltage regulator from some GM or Chrysler car that was more or less compatible with the NB alternator's requirements, and he installed that to drive the wire that controls the field intensity. In theory, once the characteristics of the field control circuit are known (a plot of control voltage vs. output voltage) it should be possible to design a simple op-amp based circuit to perform this task.

Braineack

iTrader: (62)

Once you have the schematics finalized. I should be able to get them stamped...

yertnamreg1218

So from reading this it would seem there is no actual regulator on the output voltage of the alternator. If this is the case, this is really super easy to do.

I completely agree on the opamps. I'm pretty sure I can whip something up that will automatically adjust the control voltage using negative feedback. Then we won't need to know the field voltage/reference voltage relationship, the opamp should magically take care of everything.

I took a quick look at the NB A/C and it shouldn't be that bad, maybe some comparators and a few transistors and I can get it working.

On a side note, are there any other EE/CPE's around here??