[TSloper]

I don't know what was going wrong for others but I am happy to report that there is no bug in the 2016 Camaro SS ECM that prevents the use of the Flex Fuel sensor. Rather than buy the fittings, etc. needed to install the actual sensor I created a small program that runs on an Arduino board to exactly mimic the output of the real sensor. It outputs the correct pulse width for the fuel temperature as well as the correct frequency for a given ethanol percentage. I verified the signal on a scope to ensure it was accurate.

I tested it with multiple ethanol % points and the ECM reflected the changes in the scan tool immediately. I also saw the ECM use the Flex Fuel tables correctly for the given ethanol percentage.

If anyone needs to see the proof let me know and I will post it. I'm ordering the fittings needed to install the actual sensor tomorrow. Once it is installed I will post everything needed to duplicate the install. Installing the wire for the ECM connector is a breeze. It shouldn't take anyone more than 5 minutes. The ECM changes are simple to turn this on.



Tim

[parish8]

wow! great news and good job. i am curious what roadblocks the other people were running into.

we are talking flex fuel sensor with a harness and hp tuners is all you need? plumb in the sensor, wire the sensor into the ecm, then turn it on with hptuners?

[R3DLT1]

...

[TSloper]

Originally Posted by parish8

wow! great news and good job. i am curious what roadblocks the other people were running into.

we are talking flex fuel sensor with a harness and hp tuners is all you need? plumb in the sensor, wire the sensor into the ecm, then turn it on with hptuners?

Yes it is as simple as that.

[parish8]

Originally Posted by TSloper

I'm ordering the fittings needed to install the actual sensor tomorrow. Once it is installed I will post everything needed to duplicate the install. Installing the wire for the ECM connector is a breeze. It shouldn't take anyone more than 5 minutes. The ECM changes are simple to turn this on.

Tim

hurry up!

[TSloper]

LOL

I'm trying to determine the best combination of fittings that will minimize connection points and still look clean with the factory fuel lines. I also am trying to determine where to tap power and ground for the cleanest install. I think I will get the correct connectors and build a harness that will plug inline at the number 8 coil. Then it's only one wire that needs to go to the ECM area.

I will update this list as I go...

GM 19301532 - ECM wire (this has the correct pin connector on it to insert into the ECM X1 connector at location pin 38)

Tim

[oldman]

great work, e85 is easy to get around here.

[TSloper]

Here is the Arduino code for anyone interested...

//
// This code emulates the output of the GM Flex Fuel sensor.
//
// Ethanol percentage is encoded as a function of frequency (0 % to 100 % -> 50 Hz to 150 Hz)
//
// Temperature is a function of high time pulse width (-40 C to 125 C -> 1 mS to 5 mS)
//

#define ETHANOL_PERCENTAGE 85.0
#define FUEL_TEMPERATURE 25.0 // degrees C

#define ETHANOL_PW 1000000 / (50 + ETHANOL_PERCENTAGE) // uS
#define TEMPERATURE_PW ((FUEL_TEMPERATURE + 81.25) * 1000) / 41.25 // uS

#define FFS_PIN 12

void setup() {
// put your setup code here, to run once:
pinMode(FFS_PIN, OUTPUT);

}

void loop() {
// put your main code here, to run repeatedly:
digitalWrite(FFS_PIN, HIGH);
delayMicroseconds(TEMPERATURE_PW);
digitalWrite(FFS_PIN, LOW);
delayMicroseconds(ETHANOL_PW - TEMPERATURE_PW);

}

[oldman]

It would be interesting to me to see how much e85 content fluctuates over say a year of fillups.

[TSloper]

That will likely depend on location. The northern states will definitely see less ethanol in the colder months to prevent cold start issues.

[parish8]

i have had a few boosted cars on e85 but not flex fuel. i watched the tune closely and tuned them to ~11.8/1(on a gas wideband) in the summer and never saw them drop more than 1/2 a point in the colder months.

that being said it would be great to have the flexability to run any ratio and have the ecm correct for you.

[TSloper]

I'm doing a straight E85 tune tomorrow but yes the flexibility would be nice to not have to worry if you get less than E85 or have to blend in E10 for whatever reason.

[V8SS]

This is great! Keep up the great work TSloper!!

[PRAY]

Awesome work as usual.