CRF 250 autotune (arduino)

Harbo776
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Harbo776
Hey, im working on a project where i could autotune the fuel setting via an O2 sensor and an arduino.

The O2 sensor im looking to use is this on:
http://www.innovatemotorsports.com/products/lc2.php

It needs 12v for the heating of the sensor. I will install a 5 ah battery for this.

The arduino will log the reading of the O2 sensor, TPS voltage and possible the MAP sensor.
To power the arduino i need 5V and about 50mA. Im wondering if i could power it from the electric system on the bike.
Since it doesn't need the much power. The bonus of this is more accurate readings of the TPS and map sensor since the arduino would have the same potential.

The logged data would be on an SD card. The data would be processed after riding and i would use the HRC program to reprogram the fuel map.

I would love if someone had some imput. Maybe some one have tried something simular, or had some great idears?
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MxKing809
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MxKing809 7/15/2016 4:19am
7/15/2016 4:19am
If it has EFI it must have a regulated supply to the fuel system. The only concern I would have is that the arduino may draw too much voltage away from the fuel system (I think mine requires 3.5v).... if you find the hot wire going to the throttle body (likely 12v), throw a multi meeter on it, splice in a 5 v resistor that goes to ground and retest the end of that hot wire.... if it doesn't have a voltage drop to the throttle body I would think you'll be ok.

Harbo776
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Harbo776 7/15/2016 5:46am
7/15/2016 5:46am
That sounds like at great way to check if im safe. Will try that out.
Harbo776
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Harbo776 7/15/2016 6:43am
7/15/2016 6:43am
Becsuse i can make it cheaper and more adaptable for different models. Got the idea from the power commander set.

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slipdog
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slipdog 7/15/2016 6:56am
7/15/2016 6:56am
Roger that!

Post up some photos of the finished product, good luck!
Drail24
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Drail24 7/16/2016 6:02am
7/16/2016 6:02am
Sounds like a fun project. You will need to find a way to tap into the RPM signal of the ECM. Technically, you would not be autotuning, you would be data logging... so you need to be able to reference the recorded air/fuel reading to the corresponding rpm and tps or map cell of the tuning software.

MxKing809 is correct about wiring in the Arduino. You need to pay attention to how that may affect the voltage output of the tps sensor or the map sensor. It could potentially skew the output depending on how it is connected.

Good luck!
Harbo776
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Harbo776 7/16/2016 6:48am
7/16/2016 6:48am
I will try and post updates.

Im working on an excel sheet that can process the data and bring an update fuel map. By doing this it is sort of autotuning, just not closed loop.

Im looking to pick up the rpm pulses with a wire aroud the ignition coil. Sort of like an hour meter. Fingers crossed it will stable enough.
ToolMaker 7/16/2016 8:06am
7/16/2016 8:06am
And what's wrong with using the same battery as the heating sensor and just regulating down to 5v?
TM
Harbo776
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Harbo776 7/16/2016 8:13am
7/16/2016 8:13am
I have not tryed doing something similar before. If i use the same battery, i am concerned my reading on the tps and map sensor will be unstable because of potential difference.

Please let me know if you have a different idea.
Drail24
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Drail24 7/16/2016 8:50am
7/16/2016 8:50am
Using the same battery for both would be the easiest, but I have witnessed instances where that causes the tps to have different readings... due to the potential difference, as you have stated. It will depend somewhat on the system and component grounding.

It's worth a try. Just monitor your tps voltage before and after.
Harbo776
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Harbo776 7/16/2016 9:03am
7/16/2016 9:03am
I have been looking at the voltage regulator way of doing it. Looks way simpler. Think this is the way to go. Will ground it to the same point as the electronic system of the bike. Hope it works.
Thank for showing thst version.

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