Ethanol sensors

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Ethanol sensors

Post by Midlana1 » 10 Feb 2015, 08:53

The problem (until recently) for people wanting to run ethanol is that they can't be sure what concentration is in their tank, making it tricky to ensure a correct engine tune.

There are several Fuel Composition Sensors (FCS) that can be used in conjunction with aftermarket ECUs to monitor ethanol content. The sensors below are allegedly* plug-and-play replacements for each other, outputting a square wave that conveys two bits of information:
Frequency: 50 Hz = 0% ethanol, and 150 Hz = 100% ethanol (170-190 Hz = failsafe mode, indicating fuel contamination).
Duty Cycle: 1ms = -40 degrees C, and 5ms = 125 degrees C

GM 12570260 and 12568450: Currently (2015) expensive, $300-400.
(Connector for the above, GM 88987992)

Continental 13577394: Currently (2015) inexpensive, $50-100.
(The connector for the Continental part is 13352241.)

*AEM says the Continental sensor will work with their Infinity ECU, even though their manual specifies only the GM sensor. Zeitronix on the other hand specifies that only the GM parts should be used.

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Re: Ethanol sensors

Post by Sidewinder1018 » 20 Sep 2019, 09:09

For what it's worth I built my own flex fuel kit to run off my OEM ECU(custom tune using a Cobb AP). The kit itself uses an arduino to convert the 50-150hz sent by the FF sensor to a 0-5V readable by the ECU.

If you're using a OEM ECU with a flash tuner this could work for you. I also added a fuel pressure sensor (which do put out 0-5V). All of this is readable on my Cobb Accessport. ... ?t=2810122

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