OK, I have the fundage but I can't seem to find a definitive answer. To run sequential fuel, do I require anything besides the MS3 board? Can I do it without the expander? Also I can't seem to find Brain's upgrade writeup (Ms1 to MS2). I know I've read it before....

 

you need the expander, or to build 2 extra injector drivers on the mainboard.

 

bleh, I was afraid of that.

 

The MS3X board is relatively cheap, and it really is quite slick. Since you're upgrading, the time-savings is perhaps less than if you were building from scratch, though having all of the customary circuits that are usually hacked into place (ignition drive, trigger in, IDL drive, etc) all done for you in proper PCB rather than just kludged into place with a bunch of wire is definitely a nice way to go.

If you really don't want to use the MS3X, there are a couple of other options available, though none is as clean. There's the DIYPNP Sequential Injection Kit, which is really intended to be plugged into a DIYPnP board, but could be hacked into place on an MS3 if you're desperate. Another option would be JBPerf's 4-channel board which, again, is not quite as elegant but could also be made to work.

MS3X is really where it's at, though.

 

the seq. inj. module consists of 2 1K resistors, 2 100K resistors, and 2 5N07s - incredibly simple circuit - which could easily fit on the proto area.

My question is: is it okay to pair those with the the mainboards IXD1404 circuit?

 

Thanks Joe. I'm not against the expander by any means. I'm just anxious and didn't realize it was needed for seq. fuel. I was under the impression I would only need it to run seq spark AND fuel.

I'll just wait for another paycheck and buy the whole deal.....

 

you dont need the expander to run anything, but it has all the input/output circuits built-in with its own db37 for easy wiring.

adding seq. fuel with the expander simply means plugging it in to the dautherboard with the provided ribbon, and wiring the 4 wires to its db37 connector. that's it.

want seq spark. same thing, wire the 4 outputs to their respectiable spot on the db37 to your ign. harness and that's it.

want boost, 1 wire to your solenoid.

want vss input, 1 wire to your harness

want launch control, 1 wire to your harness

get it?

 

Got it. Much simpler with the expander. I shall be patient.

 

You can upgrade to MS3 and still run your old batch fuel and wasted spark. Then convert to sequential when you have money for the expander board.

 

Yeah, I realize that, but I'm only shy about $60 of play money so I'd rather wait and get it over with. One order, one shipping charge, one, or two, or three weeks of figuring out how to make it work.... ;-p

 

Hey Scott, you have a link to your MS2 upgrade how-to?

 

Wait. I actually don't want to follow that if I use the expander though, do I?

 

do you have the VR circuit built on your board? that's the easiest way to mod for ms3, with the cam going into the ms3x. otherwise you can follow the input circuit on that build.

 

Hell, I dunno. You built it. It was a fairly early build you did for "jwarriner".

https://www.miataturbo.net/miata-parts-sale-trade-5/braineak-built-ms-pnp-harness-19669/

I made whatever changes needed to be made to put it on a '95 with your advice.

 

k. just depends. if it has the two pot resistors on the board, the VR input is easiest. it's 1 wire with a pullup.

 

I don't think I have the variable resistors. I will have to look this weekend. I seem to remember Dimitris saying something about running 2 opto circuits for MSII/III. So do I need to build these? I'm about this far_ from asking you what you'd charge me to do the upgrade, Brain. I'm plenty capable but my goal is to have this car driving well and maybe even dyno tuned before the end of March. I'm less interested in building than tuning and driving.

 

No it's not, you need 4 identical drivers.

 

Nope, no VR circuit. Is there a good argument to build it?
Also, do I need to build a tach driver? My car is a late '95 and I had to move some stuff around in the harness to get this to work, I remember making a mental note that when I wanted to go standalone I would need some way to drive the tach.

 

no, just wire the input circuit like I have on the ms1->ms2 write-up.

remove d1 and d2, repalce r12 with a 470, tachselect to xg1, 5v 470ohm pull-up to c30, 5v 470ohm pull-up to js10, iacwhatever to js10, swap spark outputs.

that's off the top of my head, don't quote me on the above.