[Jawsh_TxLsx]

Originally Posted by HyperblueSS

Oh i wasnt saying the sensor wasnt accurate, I just want to have a little redundancy. I know just because it says E85 on the pump, that doesn't always mean you're getting that. How is it sending a frequency reading with a DC power supply?

The flexible fuel sensor uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes the output signal accordingly. The electrical characteristic of the flexible fuel sensor signal is a square-wave digital signal. The signal is both variable frequency and variable pulse width. The frequency of the signal indicates the ethanol percentage, and the pulse width indicates the fuel temperature. The ECM provides an internal pull-up to 5 V on the signal circuit, and the flexible fuel sensor pulls the 5 V to ground in pulses. The output frequency is linear to the percentage of ethanol content in the fuel. The normal range of operating frequency is between 50 and 150 Hz, with 50 Hz representing 0 percent ethanol, and 150 Hz representing 100 percent ethanol.

[HyperblueSS]

OK yeah that makes sense...when you referenced frequency I immediately thought sine wave. I should have known better being that my degree is in electronics
Frequency modulation would work with a square wave and wouldn't require an AC power supply.

Originally Posted by Jawsh_TxLsx

The flexible fuel sensor uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes the output signal accordingly. The electrical characteristic of the flexible fuel sensor signal is a square-wave digital signal. The signal is both variable frequency and variable pulse width. The frequency of the signal indicates the ethanol percentage, and the pulse width indicates the fuel temperature. The ECM provides an internal pull-up to 5 V on the signal circuit, and the flexible fuel sensor pulls the 5 V to ground in pulses. The output frequency is linear to the percentage of ethanol content in the fuel. The normal range of operating frequency is between 50 and 150 Hz, with 50 Hz representing 0 percent ethanol, and 150 Hz representing 100 percent ethanol.

[EFI Tuning]

The sensor isn't extremely accurate spec wise. It is +/- 5%. The cheap vial testers are very accurate. My sensor reports 5% low on my car.

[PRAY]

Originally Posted by EFI Tuning

The sensor isn't extremely accurate spec wise. It is +/- 5%. The cheap vial testers are very accurate. My sensor reports 5% low on my car.

I hope mine is as well. I am only seeing 77%. That's what I get for going to gas stations in the middle of no where. I think with all the customers that passed through in the 45 minutes it took to pump 30 gallons I saw a full set of teeth.

[EFI Tuning]

Where you got yours the ethanol probably came right from their still. That's why it took so long to pump. Lol

[Jawsh_TxLsx]

Originally Posted by EFI Tuning

Where you got yours the ethanol probably came right from their still. That's why it took so long to pump. Lol

The home brew is usually closer to e100 lol

[HyperblueSS]

Update: So I went to the track tonight and finally got into the 11s with the best launch I've done so far. 1.8 60ft. Did two other passes but haven't been able to duplicate it yet...life with a manual lol

[HyperblueSS]

So I spoke too soon lol...did one more run before I left. New new personal best of 11.8 with a 1.739 60ft. I tried a few different ways but I got my best launch just doing it like I would do on the street...just a little bit more aggressive.

[JohnE]

Great time

Can you describe your launch technique? I just bought a 2016 SS M6 so am new to it. I assume you turn off traction control.

Also, does the flex fuel sensor allow you to use normal gas also? E85 is available near me, but not always convenient.

thanks. John

[HyperblueSS]

Originally Posted by JohnE

Great time

Can you describe your launch technique? I just bought a 2016 SS M6 so am new to it. I assume you turn off traction control.

Also, does the flex fuel sensor allow you to use normal gas also? E85 is available near me, but not always convenient.

thanks. John

Thanks...all i did was rev it up like I was leaving a red light, just slightly more aggressive, and slipped the clutch. You have to get enough RPMs though because if you dont the car tends to bog. I couldn't tell you what i launched at because I wasn't looking down lol...just went off of feel. The pass before that I didnt get enough RPMs and bogged so hard the car almost cut off. Its tricky launching with a manual car and sticky tires. With the flex fuel sensor you can run regular gas as well, as it monitors the alcohol content and changes timing accordingly.

[ParisTNDude]

Sorry, I'm really dumb about E85, but what's involved? What does the tune do for the conversion and how would that affect your warranty? I saw an 8A car run 11.7s at 120+ all day long at Holley LS Fest this year. I might try it out. Where do you find E85 fuel and can you switch between 93 octane and E85 or what?

[HyperblueSS]

Originally Posted by ParisTNDude

Sorry, I'm really dumb about E85, but what's involved? What does the tune do for the conversion and how would that affect your warranty? I saw an 8A car run 11.7s at 120+ all day long at Holley LS Fest this year. I might try it out. Where do you find E85 fuel and can you switch between 93 octane and E85 or what?

Well if you do any tuning to the car I think you may void your warranty, I have personally never had a car that ive managed to keep stock for long...but in my opinion modding the car is part of the hobby. Yeah im trying to keep up with the automatics because they have a decent advantage from the get go. Where i live there are 2 gas stations that sell E85 fairly close, and the whole point of the flex fuel sensor is that you'll be able to switch back and forth without having to change tunes. The capability is already built into the ECM, you just have to have tuning software to go in and unlock it.

[wnta1ss]

Congratulations HyperblueSS, for running in the 11s.

[wnta1ss]

Originally Posted by ParisTNDude

Sorry, I'm really dumb about E85, but what's involved? What does the tune do for the conversion and how would that affect your warranty?

For installing a Flex-Fuel kit, the tune at a minimum would need to enable the Flex Fuel function which is in the ECM (but disabled) from the factory. The ECM has a flash counter, so GM will know the car has been reflashed, and they could call your warranty void if they want to.