Heh, you too.

 

The Basic MS3 has a custom mainboard and only uses the MS3 daughterboard. It doesn't use the V3 mainboard or an adapter harness.

The latest version (V3.2c) has onboard barometric sensor, 4 spare analog inputs (all with jumper-selectable pullups), 2 VSS inputs (hall sensors), 3 spare generic outputs (PWMable), EBC output, VVT output, alternator output, battery light output, CEL output, cooling fan(s) output(s), A/C output, sequential injection and sequential ignition, onboard DSP knock sensing, realtime clock with battery backup, 4 spare digital inputs. This is common across all models (90-93, 94-95, 96-97, 99-00, 01-05), so even the 90-93 version has the alternator output if you want to swap in a VVT engine and still use the VVT alternator.

 

I meant it uses the MS3 daughterboard. Sorry if that was not clear. I was completely ignoring the underling mainboard when trying to describe the differences between all the MS3's, as I know the main board can vary greatly and really has no saying as to the feature set of the MS3.

 

I'm not sure if brain's/DIY's MS3X has generic outputs/inputs set up on it. I'm guessing that this would let you just solder in an input wire and adjust the parameter's through TunerStudio without having to open up the box, right? I.e. you can add in an oil pressure/temp gauge feed it to an input, and then get the signal through the output if you want to run warning light or such. Do I have that right?

Re: this thread.

I feel like I'm swimming in place right now, but progress is being made. I took apart the dash to get to the tach wire after finding these instructions: https://www.flyinmiata.com/support/i...isc/shifti.pdf
I'm going to feed the tach through that input and then wire things in. I'll get power from the radio power line since the gauges draw so little power. For ground can I just use the radio ground too, or am I better off using a ring connector and grounding to metal where the radio is supposed to attach? I don't want to T anything off the megasquirt cables if it's avoidable.

Hoping to take a study break for a couple of hours in the afternoon tomorrow to finish this up and hopefully start the car for the first time.

 

Well, that was a relatively productive study break!

 

Here is a general explanation that I think will help you wrap your head around everything a little better.

An ECU is a micro processor at its core. It runs code and controls inputs and outputs based on that code.

The processor had a variety of input and output pins and they all have different functions. A processor pin should never be directly connected to an outside signal because an uncontrolled signal can fry the CPU.

So every pin needs a circuit between the processor and the outside world. This is done a few different ways.

The original ms1 used the 3.0 board and the only inputs and outputs on the processor went through that main board. This was quite limited, as the main board ECU connection only has 40 pins.

The ms2 introduced the concept of a daughter board. The ms2 processor had more than 40 pins so an adapter board (daughter board) was used to connect the new processor to the old main board.

Then comes the ms3. This processor had a lot more I/O so it used the circuits on the main board but then also had 2 sets of expander pins. These expander pins were direct ECU pin connections and could be connected to the ms3x which provided all the circuitry needed to use the extra pins.

I know we're a bit off topic but it all comes around.

Go google the ms3x pinout. You will see all the available inputs and outputs when using an ms3x card. These are available on the top DB37 connector, which you will need to take apart and add new wires too.

Start there and go explore some. When you have more direct questions about specific functionality post them here, but you are lacking a bit of general understanding before you go wiring up random inputs and outputs.

 

Thanks Aidan.

I'm just getting the gauges in for now and I think I have that mostly sorted. I'll go through the manual again. I'm aware of most of what you said, I was just unsure if the circuits were already built in or if they needed to be modified for additional I/O.

But yes... Manual.

 

Got all the gauges wired in last night... who am I kidding. I finished at 4 AM. Tried to turn them on and the radio was on the fritz. I went back today and redid all the PO's electrical tape joins with butt connectors and it fixed the issue.

The wideband (connected to MS) still wasn't turning on though. I started the car and it started then died. I don't have much time to investigate today, but my next step will be to check and see if the MS3 is getting a wideband input.

I have an AEM Uego, which brain's manual states might need a 10A fuse instead of the 5A that he includes. I checked the fuse and it wasn't blown so I'm not sure what's up. If it's a power issue, I might try to wire it in with an add-a-fuse and see if that fixes things, but I'll take a multimeter to things before I do that.

Never a dull day!

 

Started then died sounds like possibly a bad ground. Slowly but surely, you're almost there

 

Hmm. Would that explain the afr gauge not working?

Unsure how I could have a bad ground if things are connected to the ecu cables directly. I mean I guess they could be off, but that would mean the main grounds are bad right?

 

I mean if you used T-taps or butt connectors, I can't tell you how many times i crimped them down and it was a really bad connection. I only solder stuff now

 

Haha, *****, now you have me second guessing things. I guess I have everything required to go in and solder it.

I did use butt connectors though.

 

I posted a thread in the megasquirt section because I'm having a helluva time trying to get the wideband working.

Here's a link to the thread so this all stays together: https://www.miataturbo.net/megasquir...2/#post1395223

 

My used fm1 clutch setup came with a lightweight flywheel.

I'm on the fence about whether to use it or not. It's a 13lb unit, but I wonder if it's overkill and if it will make the car annoying to drive if I ever get stuck in traffic.

I can probably sell it and put the money towards something more useful in this build.

 

Vibration and solder (specifically wire that wicks the tinning up) don't mix. Ive never had a proper crimp fail or make a bad connection. Don't crimp on the insulation? Use the right crimpers for the job....

 

13 lb is a heavy flywheel. I noticed very little difference with the 10 lb happy meal flywheel, compared to stock.

In regards to the crimp/solder ordeal. I use un-insulated crimps. I insert the stripped wire so that the wire insulation just barely protrudes into the crimp (maybe 0.050"). I crimp over just the portion of stripped wire, and make sure that the crimp does not squeeze the insulation at all (ie: the crimp is only squeezing on the wire strands). Then I do a pull test to make sure that the crimp is grabbing the metal wire properly. Then I lightly crimp the end of the crimp where the wire insulation is, until it's just slightly compressing the wire insulation. This provides some extra friction to keep the splice in place. Then I finish with glue embedded heat shrink over the whole splice.

 

I was using them for behind the radio. It held up with electrical tape for years so yolo.

I was actually using the heat shrink butt connectors then putting heat shrink over them because it seemed more secure. I like your idea of using regular ones though. The ones for megasquirt were basically to test connections. I'm working with scott to figure out what's going on. Seems like it's likely an MS issue.

Re: flywheel. Goes back to a discussion re power pulses and transmissions. I'm only shooting for 220-230 but I have a 5 speed. I feel like keeping the stock flywheel is erring to the side of mechanical empathy, no?

 

I'm running the 12lb steel flywheel instead of the 18lb stock one. It was one of my first modifications back in 2008, before that discussion occurred. I wouldn't go any lighter than that.

I like the difference it made in revving and shifting but it probably contributes to the engine trying to stall when the air conditioner engages as well. Interesting series of trade-offs.

 

I had a 12lb flywheel, it would stall with the stock ecu, mostly when running the a/c. I'm sure ms3 can prevent it better than the stocker, but the rpms drop FAST.

 

Yeah, these are fair points.

I'm trying to keep AC as this is a street car, so it seems like staying stock is probably a good idea for multiple reasons. Reasons that can probably properly addressed, but there's always a tradeoff.

Brain, are you on a stock flywheel now?