You can safely run leaner on E85, and it's worth some power. So much of the fuel you inject in boost is used to cool the combustion chamber, and that's just not needed with E85. You can safely play in the low 12s (gas scale AFR) on E85.

I ran three dedicated wires back to the OEM harness and grounded the sensor at the MS3 Basic's DB37. No issues. Where is yours grounded?

My ethanol % is very consistent, a 20 minute datalog will show a few tenths (less than 0.5%) variance. Braineak ran my flex sensor through the Evap purge wiring which was very convenient and seems to work great. I just grounded the sensor to the body close to the sensor.

Interesting. I need to wire mine up. I didn't run dedicated wires, mine share a power and ground with my fuel pressure sensor.

Thank you all for the mixture information. I am not boosting since its a lowly CSP autox car. I will assume the same applies to N/A as does to F/I.

As for the flex signal, I used my factory o2 sensor connector to run the flex sensor. I just cut the sensor off and had four wires to splice into that had 12v, ground, sensor ground, and signal. I triple checked that I was using ground and not sensor ground. The ground comes from joint connector, left side of instrument panel according to Mitchell wiring diagram. Perhaps a quick check of that ground might solve it. The signal from flex goes back through the o2 sensor wire to the factory ecu connector and is shielded at joint connector at right side of instrument panel which then goes to engine block, according to Mitchell. I de-pinned the sensor ground wire. It's most likely the ground to the body and not the engine that is causing the problem. At least I hope.

https://www.miataturbo.net/attachmen...ine=1467063609

Bringing this back from the dead one more time just to give some results. I did the procedure as Sav recommended. I have yet to tune anything other than the VE table. The engine runs better on corn or so my butt dyno says. Everything seems much crisper. And it seems to like running on the lean side of gas stoich.

Did an autox in Ft. Myers and had to fill up with gas as no corn was available and the tank was dry. Did not change to the gas VE table as I was lazy and never got around to doing it. It runs slightly rich with gas when on the corn VE table so you definitely need to have the two tables and not just let the global fuel multiplier do its thing.

I really am liking the way the engine runs on corn. I don't know if I'm playing with fire by having not changed any of the hardware. Pump, lines, injectors are all factory. Fuel filter was replaced as regular maintenance maybe 10k miles ago. Data shows 90's on injector duty cycle at redline but with good fuel control. If I were to get a new set of injectors, which way should I go? Presently they are 2001 VVT injectors run at constant 60 psi with a return system of course. It just seems the new standard of FF 610's are a bit much for a NA 1.8 engine making 150 to the wheels.

And I am also liking the way the car smells with corn. With no cat on the car and just a turndown before the axle, the emissions at idle always used to bother me. Hell sometimes when the wind was in the right direction the emissions used to get in the car while on the hiway. For whatever reason the corn emissions don't seem to bother me. I have heard people complain about it when being behind a car that is on corn though but I only autox so....

Which got me thinking: is ethanol not as polluting or maybe even zero pollutant? I know its e85 I'm running (more like e70 most of the time) but compared to gasoline what are the HC, COx, and NOx emissions like? I'm not talking about carbon footprint yada yada. I'm talking about tailpipe emissions, anyone ever sniffed their tailpipe on corn?

And then there is this: Study: Biofuels increase, rather than decrease, heat-trapping carbon dioxide emissions | University of Michigan News

But that gets into the ugly world of politics and conjecture and forecast science and I don't want to go there.

I'm obviously super ridiculously biased, but you don't need to be at the top end of the power capacity of FFs to run them. Even in a stock car running on pump gas, the fuel atomization and valve precision is an upgrade from stock injectors. :party:

One of these days Hector, we need to get the two cars on the dyno...

I might be scheduling some time coming up, want to join me? We can split two hours? LOL.