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DIY E85 How to?

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Old Jul 12, 2025 | 02:40 PM
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Default DIY E85 How to?

Just put flex fuel in a 2018 gti. very easy and simple. But for my Miata I wanna do the same because I won’t have access to 93 anymore. So for a parts list I found some 650cc injectors and the gm flex fuel sensor off fab 9. I know one wire for ground, power, then the one for the ecu. How do I do that? It’s a 1990 on a speedyefi. Do I make a pin like I did for the gti? Or do I have to open the board and solder? Can’t find much online so thought you guys can help. Any videos and pictures are hugely appreciated because I’m a visual learner haha. Thanks!
Old Jul 16, 2025 | 12:04 PM
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I was literally poking around to figure out where to do a writeup on how to add flex fuel lol. I guess there is some demand.
Old Jul 16, 2025 | 01:25 PM
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Originally Posted by SimBa
I was literally poking around to figure out where to do a writeup on how to add flex fuel lol. I guess there is some demand.

pleaseeeee do I need to know
Old Jul 16, 2025 | 03:26 PM
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I did a write up which is like 1 post above this one.

I didn't cover running the wires to the ECU. The Speeduino should have a dedicated flex pin which you'd need to get the signal to.
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