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Thread: Flex-fuel sensor output

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Posts: 41-50 of 72
2015-04-10 00:40:35
@D-Unit121 how close was the analyzer to the ethanol rating. I'm curious due to changes in winter and summer blend consistency.
2015-04-10 05:18:27
Flex-fuel sensor output
Originally Posted by ebinkerd
@D-Unit121 how close was the analyzer to the ethanol rating. I'm curious due to changes in winter and summer blend consistency.

It seems to be 100% accurate. I did not invest in one of the test tube to check the ethanol content but those are only accurate to -5,+5%.

To determine the ethanol content coming from the pump I first sat down and did some math. Then I started thinking with my dip stick and used a online calculator. My math matched the Web site so I can vouch for its accuracy. You can find it here.


I ended up getting e70 from the pump.

Just to break it down for you a little. I have a 13.2 gallon tank. In the tank I had 3.1 gallons of 93 octain with a 8% ethanol content. I added 10.1 gallons of e70. This left me with a e55 blend with an octain rating of 100ish.
2015-04-10 13:48:10
This is awesome. A low cost hassle free ethanol analyzer. Can one of you post the complete schematics?
2015-04-10 14:11:54
Flex-fuel sensor output
I do not have any pictires of this but for the arduino power source I used a 12v wire from behind the dash and ran a 5v restrictor inline. From there I used the 5v power to install a female usb plug in the car. I connected the arduino into that plug and it fires up. I'd say that is the easiest way to have power and ground. The restrictor was about $2.50 at radio shack.

I'm going to assume this is what you are really after. Please note that I had to modify my code to run on output pin 3 instead of 11. Pin 11 was giving me issues.

Here is another picture showing the jumper that needs to be wired in and what the arduino output to the ecu should look like. While looking at this picture please notice that I did have to modify my code to run on pin 3 instead of 11.

And a better picture of the jumper
Last edited by D-Unit121 on 2015-04-10 at 16-34-11.
2015-04-10 15:13:10
Which LCD shield is that?
2015-04-10 15:27:08
Its the 1602 button shield

Here is the combo i purchased for the project.

Uno R3 Board LCD Button Shield Cable Arduino Compatable Free Bonus Gift Inc | eBay

and if you are wondering the bonus gift was three led lights.
2015-04-10 16:04:05
Damn that's stupid cheap.
2015-04-10 16:17:12
Flex-fuel sensor output
While we are on the subject of keeping things on the cheap...

I found the connector for the flex fuel sensor to be crazy expensive. The cheapest I could find it for was $20.

One night I was staring at my flex fuel sensor and it hit me. A standard gm connector would work with a little modification.

You have to cut two tabs off the sensor it's self and then this connector fits like a glove.

Delphi GT 150 series connector part # 13519047 is what you will need.

Here is the the original sensor.

Here is the modification I made. I did this with a razor blade and some sand paper.

The plug slips right on and is a very tight fit.
Last edited by D-Unit121 on 2015-04-10 at 16-19-34.
2015-04-10 17:40:14
Haha, I did the same thing! That's pretty funny. You can also get the other style flex sensor with the Delphi 150 connector without modification.
2015-04-10 19:16:26
I'm going to check the ethanol content between this and Johan's Bluetooth ECA and our manual alky bobber that we use for meth/water content. See how they all compare to each other.
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