jeffdurrum

I'm currently installing my DIY MS2 into my 1994 1.8l Miata and I'd like to post my progress and maybe solicit a little advice.

For now I'm just going to use it for fuel and leave the stock ecu to handle ignition. Later, when I'm more confident, I'll set up the MS2 to handle both fuel and spark.

I've assembled the MS2 and done the mods as described in the diyautotune article "How to Megasquirt your Mazda Miata" In a nutshell, those mods are: 1k resistor from JS10 to SPR3. 470Ohm resistor from 5v to SPR3. 470Ohm resistor from VRIN to 5v. 0.01 uF cap from JS10 to ground.

I have the diyautotune MSPiggy and I'm making a sort of DIY boomslang. I got a ecu type socket from Mouser, part number 17917-6, and a plug from Ballenger motorsports. As soon as I finish wiring that up, I'll plug it see if everything works.






What I'd like to ask everyone is:

Do I need any addition mods to the board, other than the pull up resistors and lowpass cap mod?

Any advice on wiring up my "Boomslang" I've looked at a few wiring diagrams, but I'm still a little uncertain. The following diagram seems to be what I should follow, but I'm not sure the wire colors match the mspiggy harness exactly.

hector

Wow, MS2 and not even a DIYPNP. You are a brave man. I don't know that you will get a whole lot of advice here for this as this is just too old of a tool anymore. I'd wager most people who built one when it was current don't remember anything about it. Even the code hasn't had a new updated release since 2015 although a beta seems to have popped up in 2018.

I would suggest contacting DIYAutotune with any questions you may have. Their tech department has always been useful to me and email responses have always been in an acceptable time frame.

The other thing I would suggest is to ask on here: Megasquirt Support Forum (MSEXTRA) ? MS2/Extra, MS2, Microsquirt and Microsquirt module support (View forum)
Since these are current users of MS2, you might be able to get more responses.

As far as the boomslang, don't trust anything if you're not sure. Backtrace and make sure you are using the right connection and document things for yourself.

WestfieldMX5

Don't do a parallel install, replace it directly with the Megasquirt, you'll have less trouble setting it up.

jeffdurrum

WestfieldMX5, I 'm wiring the boomslang to just pass the sensor input signals to the stock ecu. I was planning on only using Megasquirt for fuel while leaving the stock ecu to handle ignition. Then, when I'm confident the Megasquirt is working correctly, have it take over ignition too. Do you think that would be too difficult? Do you suggest I just go for both fuel and spark on the Megasquirt right now? I think that would be doable.

jeffdurrum

hector, Do you think ms3 would be easier? I could get the ms3 daughter card and use it in the pcb I've already assembled. Good idea on simply contacting diyautotune, I don't know why I haven't considered that.

hector

Jeff, anytime you put together an ecu that requires a separate main board it just becomes more difficult. Especially when building on a generic application ecu. That's why IMO a DIYPNP is easier to build and run since it is built for a particular application and you have plenty of documentation all over the web.

So while MS3 is better for sure, you may still be asking the same questions. It seems to me you have a really good grasp of the situation building the mainboard and getting all the circuits fed with proper pots and caps so I would say just keep plugging along. I would definitely do as Westfiled suggested and go stand alone. IMO, you will be giving yourself more work by doing a parallel install.

My question to you is, where do you want this ecu to take you? I bought and built a DIYPNP many years ago. It was great at the beginning. Then as I got further along in the project it just ran out of I/O and I got tired of dealing with the inferior idle and other firmware deficiencies. So if all you are looking for is just a basic install that you know you won't need anything more out of in the future, stick with what you have. If you know your project is going to grow in the future, save your money on the MS3 card and use it to buy a MS3Pro module and one of Westfield's adapter boards. IMO, that is the best Miata solution out there today. While the MS3 daughtercard will give you MS3 firmware function, you will need the MS3x card to have MS3Pro capability and still more pots and caps and jumper cables to wire up. Lots of luck whichever way you go.