Originally Posted by wreckleford

What I found though is that the ethanol content reported fluctuates a little bit, jumping down to 17% momentarily and back up to 22%. I'm wondering if this is corresponding to changes in my battery voltage (it fluctuates somewhat) or if this is to be expected.

Originally Posted by edsct9a

Now my gauge is able to output a 0-5v signal would this help? What's the converter circuit for? I'll go back and read tomorrow but maybe you can summarize what's been going on or point me to key posts.

Originally Posted by cdrinkh2o

If you already have a 0-5V analog output from your Innovate ethanol content gauge, you don't need to build the converter circuit. All the circuit does is to convert the frequency output from your ethanol sensor into a voltage that can be read by the ECU.

Just connect your gauge output to the ECU pin that is used normally for map switching:
- Evo 8 4-plug ECU: pin 42
- Evo 8 3-plug ECU: pin 64

Follow the steps in the first few posts to patch your ROM and start tuning!

Originally Posted by cdrinkh2o

Congrats on the progress you have made Wreckleford - about time too

Changes in battery supply voltage are smoothed by the voltage regulator (LM317) in the circuit you built. A fluctuation of +/- 2.5% in your output voltage (=E%) is within the tolerance expected for the output side of your circuit.

An input variation of +/- 2.5% is easily good enough to drive the FlexFuel routines in the patched ECU without adding risk. Don't you think it's time to turn it on and start tuning?

Originally Posted by cdrinkh2o

If you already have a 0-5V analog output from your Innovate ethanol content gauge, you don't need to build the converter circuit. All the circuit does is to convert the frequency output from your ethanol sensor into a voltage that can be read by the ECU.

Just connect your gauge output to the ECU pin that is used normally for map switching:
- Evo 8 4-plug ECU: pin 42
- Evo 8 3-plug ECU: pin 64

Follow the steps in the first few posts to patch your ROM and start tuning!

Originally Posted by wreckleford

After many many months I finally started my car with the converter circuit and ethanol content sensor connected. I put a couple gallons of pump fuel in the tank to start with. I measured this with my ethanol tester beforehand and found it to be E07. This showed as E06.9 with the voltage to ethanol percent scaling I used in Evoscan. Threw a half gallon of E98 into the tank and got E22 registered which is roughly correct for the amount I added to the original pump gas. I intend to drain a little bit and check it in the tester also but haven't done so yet.

At this point I am not making use of the free fuel patch rom, just logging ethanol content. The 02 feedback is adjusting for the additional ethanol currently. What I found though is that the ethanol content reported fluctuates a little bit, jumping down to 17% momentarily and back up to 22%. I'm wondering if this is corresponding to changes in my battery voltage (it fluctuates somewhat) or if this is to be expected.

I will update further when I actually implement the patch. At the rate i am going it might be several more months.

Originally Posted by ast

Nice to see that some people are using FreeFuel in the US and are happy with it.

I wonder if anybody in the US would be interested in adapter / converter designed for FreeFuel to convert sensor signal to ECU analog input. It's a fully digital adapter designed by me. Unlike analog solutions output voltage range is optimized to allow using safety features built into the FreeFuel patch and maximum ethanol content resolution. Output is also very stable is much faster to react to sensor signal change than analog designs. It is currently in use in some cars in Finland with good feedback. Installation is made as simple as possible: just pull one wire through firewall to engine bay, push pins to sensor connector frame and solder three wires to ECU.

Price would be around 100 USD shipped to US from Finland. Not sure if you have to pay taxes on top of that.

I have attached a spec sheet to this message.

I would appreciate if the discussion of the other FlexFuel solution, apparently called FiTronic, would be kept outside this thread. As far as I know it has nothing to do with this patch and it can be extremely confusing to mix the discussion about it here. Thank you.

Originally Posted by turbotiger

Which sensor would this work with?

Originally Posted by wreckleford

After many many months I finally started my car with the converter circuit and ethanol content sensor connected. I put a couple gallons of pump fuel in the tank to start with. I measured this with my ethanol tester beforehand and found it to be E07. This showed as E06.9 with the voltage to ethanol percent scaling I used in Evoscan. Threw a half gallon of E98 into the tank and got E22 registered which is roughly correct for the amount I added to the original pump gas. I intend to drain a little bit and check it in the tester also but haven't done so yet.

At this point I am not making use of the free fuel patch rom, just logging ethanol content. The 02 feedback is adjusting for the additional ethanol currently. What I found though is that the ethanol content reported fluctuates a little bit, jumping down to 17% momentarily and back up to 22%. I'm wondering if this is corresponding to changes in my battery voltage (it fluctuates somewhat) or if this is to be expected.

I will update further when I actually implement the patch. At the rate i am going it might be several more months.

Originally Posted by 3VOLUTIONIST

I run 90550701 (Evo 7) Tephra v7 currently, and plan to switch to SD after I finish my engine swap. Am I dreaming when i comes to wanting flex fuel?

Originally Posted by tscompusa

Can be done on FiTronic 3VOLUTIONIST. The kit cost money though, Because it comes with hardware & display.

Originally Posted by 3VOLUTIONIST

I run 90550701 (Evo 7) Tephra v7 currently, and plan to switch to SD after I finish my engine swap. Am I dreaming when i comes to wanting flex fuel?