Openflash FLEXFUEL OTS Tunes!

[MaxxCann]

Originally Posted by solidONE

You cut the evap signal wire?

Yes, but I spliced in a switch so I could run it stock when I want. Waiting initial flash for the flex fuel kit from Shiv

[MaxxCann]

Has anyone started the custom tune process yet?

[solidONE]

Originally Posted by MaxxCann

Yes, but I spliced in a switch so I could run it stock when I want. Waiting initial flash for the flex fuel kit from Shiv

Good idea! Though I'd personally rather run a fresh wire and pin/connector to avoid cutting the stock wire if I can.

[customyota]

Originally Posted by steve99

It should work with any flex kit set up to connect into the evap pressure on the ecu.

you may need to tweak the tables for e% vs voltage if their are differences in sensor calibration most kits put out 0 to 5v.

you can also just switch the evap inut from earth to open circuit as the ecu has an internall pull up resistor to 5v, this give you basicly e85 to petrol map switching on the fly no reflash needed and cost you $5 for a switch.

That seems strange, how does the ecu read accurate values from the sensor if the pin is pulled up? I can see pulling it to ground with a switch, but if the kit is just supplying a voltage, wouldn't the pull up cause it to read 5v all the time?

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[customyota]

Originally Posted by solidONE

Good idea! Though I'd personally rather run a fresh wire and pin/connector to avoid cutting the stock wire if I can.

It's 90 bucks, but you could use the visconti harness to add the wire without cutting anything.

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[steve99]

Originally Posted by customyota

That seems strange, how does the ecu read accurate values from the sensor if the pin is pulled up? I can see pulling it to ground with a switch, but if the kit is just supplying a voltage, wouldn't the pull up cause it to read 5v all the time?

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https://en.wikipedia.org/wiki/Pull-up_resistor


The pull up resistor is likely around 5 - 10k ohm, the flex kit (or switch to ground) or switch will effectively "over ride" the pull up resistor as it will be much lower impedance.


in this case its an analogue input but the idea is still same

[customyota]

Originally Posted by steve99

https://en.wikipedia.org/wiki/Pull-up_resistor


The pull up resistor is likely around 5 - 10k ohm, the flex kit (or switch to ground) or switch will effectively "over ride" the pull up resistor as it will be much lower impedance.


in this case its an analogue input but the idea is still same

I do a lot of microprocessor stuff as a hobby, so I'm familiar with using pull up resistors on digital circuits, ie. the switch to ground, but I never considered it for analog circuits. I just figured it wouldn't work. Guess I need to do some research.

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[steve99]

Originally Posted by customyota

I do a lot of microprocessor stuff as a hobby, so I'm familiar with using pull up resistors on digital circuits, ie. the switch to ground, but I never considered it for analog circuits. I just figured it wouldn't work. Guess I need to do some research.

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I think its just their to stop it flapping round on say Australian ECU as we have no connection to that evap pressure input. or if the evap pressure sensor sensor goes bad or the sensor/wiring open circuit on vehicles with it fitted the ecu will see 5v on the line and likely trigger a CEL code. conversely if shorted to ground likely triggers cel as well as normal sensor range would be exceeded


They do similar thing on MAP sensor input to they can trigger out of range CEL codes if sensor is out of range


Yes it will effectively limit the voltage range available to something like 0.5 to 4.5 or something like that


more detail here
http://www.ft86club.com/forums/showthread.php?t=94751




specific post here
http://www.ft86club.com/forums/showp...7&postcount=11

[customyota]

Originally Posted by steve99

I think its just their to stop it flapping round on say Australian ECU as we have no connection to that evap pressure input. or if the evap pressure sensor sensor goes bad or the sensor/wiring open circuit on vehicles with it fitted the ecu will see 5v on the line and likely trigger a CEL code. conversely if shorted to ground likely triggers cel as well as normal sensor range would be exceeded


They do similar thing on MAP sensor input to they can trigger out of range CEL codes if sensor is out of range


Yes it will effectively limit the voltage range available to something like 0.5 to 4.5 or something like that


more detail here
http://www.ft86club.com/forums/showthread.php?t=94751




specific post here
http://www.ft86club.com/forums/showp...7&postcount=11

Awesome, thanks for that!

[ztan]

Have not been active here for most of the year, but it is good to see that the coding work that I did is getting put to use. I hope it works well for other drivers.

The A01G code that I have wrote and sent to Shiv has been working for me without any problems for the last 9 months. Initial test plot of E% vs STFT+LTFT attached during daily drive logs (CL operation, no filter for deltaMAF) - I have ended up going to a 1.4 multiplier at the E85 end of the scale.

For detailed decription on the coding is done and how the hardware works with this ECU see my original post:

http://www.ft86club.com/forums/showthread.php?t=94751

I haven't had - and probably won't have - time to port to other ROM versions as I only run a A01G ECU in my car. Please don't ask as I simply don't have the time or a suitable test car.

[bryansuriel3]

Can I just send you it through email?


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[bryansuriel3]

Ahhh wrong place to post


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[Aussie]

Originally Posted by ztan

Have not been active here for most of the year, but it is good to see that the coding work that I did is getting put to use. I hope it works well for other drivers.....

@ztan thanks so much for the work you did in helping to create the flex fuel kit for the OFT community. I will be installing the OpenFlash/FFTEC XRP Flex Fuel Kit on the weekend and am looking forward to stress free flex fuel driving.

I am also currently building a simple Arduino based climate control system that will toggle the A/C on and off to maintain a user defined temperature for my 2013 FR-S. As that system will include a small LCD screen I was also wanting to display the current fuel ethanol percentage. I understand the output from the kit is a 0.5v to 4.5v voltage level. My question is:

Is there a formula between voltage and ethanol content that I can use? If it is a linear equation (EthanolPercentage = xV + y) I can easily find x and y by looking at the percentage displayed on the OFT with a couple of different fuel mixtures, if it isn't it will take a bit longer. I'm hoping this information is something you can share.

Thanks

[steve99]

Originally Posted by Aussie

@ztan thanks so much for the work you did in helping to create the flex fuel kit for the OFT community. I will be installing the OpenFlash/FFTEC XRP Flex Fuel Kit on the weekend and am looking forward to stress free flex fuel driving.

I am also currently building a simple Arduino based climate control system that will toggle the A/C on and off to maintain a user defined temperature for my 2013 FR-S. As that system will include a small LCD screen I was also wanting to display the current fuel ethanol percentage. I understand the output from the kit is a 0.5v to 4.5v voltage level. My question is:

Is there a formula between voltage and ethanol content that I can use? If it is a linear equation (EthanolPercentage = xV + y) I can easily find x and y by looking at the percentage displayed on the OFT with a couple of different fuel mixtures, if it isn't it will take a bit longer. I'm hoping this information is something you can share.

Thanks

V_out = 5 - (0.05 * ethanol);




see ztans post here , coding


http://www.ft86club.com/forums/showp...7&postcount=11




however I believe ztans ethanol sensor circuit is opposite sense than the commercial sensors


ie ztans coded E0 to send 5V and E100 to send 0V
but commercial units E0-0v and E100 5V


or in practice will be about 0.5v to 4.5V