MS3 harness wire schematic - what do you think?
 

I've got the majority of the MS3 harness for Ford Monster Miatas (and Mustangs) worked out in a schematic. I used the posted schematics posted at ms3extra, advice from the folks at diyautotune and my own knowledge of early 90's Ford fuel injection to create this:

http://www.msextra.com/forums/downlo...e.php?id=22566

What do you all think?

I designed it for sequential injection (so I'll be ready to go when the code is out) as well as EGR and evaporative system control using available 12 volt outputs. I added the Ford VSS sensor in with a GM HEI module to change the hall-effect output of the VSS to an on-off signal for the ECU and then ran it to one of the available 12 volt switchable inputs as per diyautotune's instructions (I still need guidance with exactly how to hook this up). I used one of the available 12 volt outputs to control an electric fan and two others to control a shift light and a data logging monitor light. I'll be using two innovate widebands with controllers, the stock 1991 Mustang TPS and IAC, GM air and H2O temp senders to keep setup simple, and red 31 pound injectors from a flex-fuel Explorer. I'll have two toggle-switch controlled inputs for the data logging and launch control (and another for traction control if I can figure out how to add it in).

How's all this look? I'm a little concerned with the fact that, unlike a 1991 Mustang, there is no master 30 amp fusible link coming off the battery. I'll probabaly end up placing one where the "?" is on the schematic. Also, I'd really like to take advantage of traction control when the code exists. I may wire in a witch for that now if i can figure out where to put it.

The only real problem I ran into is how to hook up the GM HEI module with the Ford VSS. Does anyone have any experience with using a GM HEI module to alter the VSS signal? It looks pretty simple (the module has two inputs and two outputs) but it would help if someone had done it before.

Thanks all, remember the above is IN NO WAY COMPLETE and should NOT be used as a guide for wiring a MS3 into a Mustang. If anyone feels compelled to add to the diagram and repost it please do so.

Jason McCully

Very nice. I have been interested in the Megasquirt for years. This may put me over the edge. Might even be worth bartering a subframe. :)

Mike

U R a rock star!

I'm generally smitten with the whole free software movement (of course MS isn't a pure play on free software...http://en.wikipedia.org/wiki/Tivoization) but I'm not too hung up on that...great work & keep the details coming.

Just a note of caution to anyone planning on using the above: there are a few big mistakes in that that I have since fixed. I'll post up the revised one soon.

-Jason

Here's the updated version that I'll actually be building. I have a separate schematic for my widebands as well:

https://www.v8miata.net/picture.php?...&pictureid=291

-Jason

Superb! Generally I never read whole articles but the way you wrote this information is simply amazing and this kept my interest in reading and I enjoyed it.