New wiki and manual has launched! Check it out at
Any questions you have before you begin buying, building and installing.
Yes those links work, thank you. I wasn't familiar with what github was or navigating it, I've taken some time to become more familiar with it.

Thank you everyone for your responses. I'm going to sit down and take a good while to really read through as much as I can on these forums and through the documentation before I ask anything else, though I do still welcome any advice regarding hooking it up to GM HEI- I haven't found too much relevant there. I may try my hand at soldering up the board but looking through the prices of things the completed board is a very reasonable price.

Once everything is in my hands and I get some time off work to swap in the parts, I'll post build progress on hooking everything into speeduino.

Yes, with speeduino it looks like I could move to coil near plug, or LS1 coils, or any sort of modern ignition system if I put the time into it and installed some sort of CPS.

I would like to continue using the 1991 5.7l TBI system as "stock" as possible though (which is the GM 8 pin HEI ICM as far as I understand), as I do not have very much money, which is why I am looking into speeduino in the first place. I already have the other parts on hand and the engine needs the rebuild anyway. In the future I will be looking at replacing many things, but overall I actually hoped it would be easiest to do this with such a primitive electronic system- after all, there is almost nothing to it.

While I may not be the person most suited to it, I also hope I can document the process well enough to make it an easy thing for anyone in the future looking to do the same thing- I believe speeduino is an ideal ECM replacement for these older vehicles- the computers are ancient and getting unreliable and expensive, and you have to go through expensive reflashers or spend hundreds of dollars just to perform minor tunes on them.
Ford Sierra 2.8 V6

What board have you got? Or getting? You can incre[…]

VW 2.0 ABF 16V

So it was time to get the engine back in where it […]

Use MAP acceleration enrichment instead of TPS […]

I realise this post is a year old but....did you […]

Still can't find what you're looking for?