Flex fuel sensor?

[RedSRT4Me]

Do we have a flex fuel sensor that can switch maps based on the amount of E in the tank? I see other models have this ability and I'm curious if we have the same.

 

[gixxer]

I’ve always wandered this too.

Would it be able to tell if you have premium and advance the timing?

 

[RedSRT4Me]

I’ve always wandered this too.

Would it be able to tell if you have premium and advance the timing?

Not so much premium but the ethanol content provides a race gas like octane such as E85. It would be sweet to just fill up with E85 and the truck knows exactly what to do with it

 

[BiGMERF]

Curious also, as I was ripping off the flex fuel badge. Lol

 

[Wahrsuul]

Don't think the US 5.7 is Flex Fuel capable.

 

[gixxer]

There would have to be a sensor. The Porsche’s have a sensor so if people put in crappy fuel it adjusts before the engine has a chance to experience knock. So I was told by the dealer.

Chevy Cobalt SS has this as well apparently.

It might take a tank or two to familiarize itself.

I wanted to try it but the cost was way too much for me.

 

[Barney556180]

All modern engines have knock sensors to adjust timing according to the octane (the propensity to knock/ping under higher compression) .
The computer advances the timing and dwell forward (for best efficiency) and dials back if knock/ping detected. This provides optimum tune for whatever’s in the tank.


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[Tach_tech]

All modern engines have knock sensors to adjust timing according to the octane (the propensity to knock/ping under higher compression) .
The computer advances the timing and dwell forward (for best efficiency) and dials back if knock/ping detected. This provides optimum tune for whatever’s in the tank.


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The PCM won’t adjust timing any further past it’s max advance though. So if 87 is recommended, filling up with premium will have no benefits.

 

[Barney556180]

True. If an engine is designed for 87, and it doesn’t knock under low-speed acceleration, then higher octane is a waste of money.

The big benefit is if using a lower octane than specified, the PCM will dial back to protect the engine against knock/ping damage.


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[stimpy433]

The dealership told me that there is some kind of sensor and when switching between E85 and regular gas i should wait til the gas tank is as empty as possible so not to “confuse” the computer.

 

[clay282]

Seems to me, E85 runs smoother with more power... I wondered if it was just in my head, so I tried to find out. This has been going on for YEARS! I think it was a 2002 Taurus I had with a Vulcan V6 and they pinged all day long. I'd run E85 and it would stop pinging and run better for a month, then back to pinging. I've actually read in a couple places that E85 makes a bit more power. Since I've always run a tank of E85 here and there in place of fuel treatment to keep the fuel system and build ups cleaned out, I've tried to figure out what's real and what's hype. The only consistent info data of E85 versus gas I can find = E85 burns cleaner and is more corrosive so it cleans things out.

I can't tell if there's a definite on how much more power it makes but several tests show it does make about %5 more power. On the other hand... Premium fuel doesn't seem to increase power any if your motor is rated for regular pump 87 octane. E85 does burn faster so your MPG will go down, but I've been getting 17 on the current tank I'm running through, so the drop isn't unbearable... especially at the $1.99 a gallon I got it for.

Of course, this info is from the internet so the reliability is not uniform. The one thing I did take away from what I've read is - If you have a flex fuel vehicle that calls for cheap regular gas, they don't seem to increase power if you move up the octane scale, but will see slight power increase with E85. Vehicles that require Premium or higher octane, don't see power increases with E85. I assume the factory tune for 87 pump allows for you to increase and the factory tune for Premium pump doesn't allow you to decrease. This is probably why a "tune" will require a specific octane. There is a sensor but it's not that easy. They can tune for octane but you still have fuel supply and corrosion issues associated with E85.

I have tried to find tunes for E85 and they do have them, but they're very specific to engine and very limited in number. I've searched for an E85 tune because my thinking was... If they could tune it for E85, keep the power level the same and keep the mpg the same = that would be a real money saver! Unfortunately they just seem to tune E85 for racing and daily driving isn't a priority.

 

[RedSRT4Me]

All modern engines have knock sensors to adjust timing according to the octane (the propensity to knock/ping under higher compression) .
The computer advances the timing and dwell forward (for best efficiency) and dials back if knock/ping detected. This provides optimum tune for whatever’s in the tank.


Sent from my iPhone using Tapatalk

The answer is appreciated but it doesn't answer any of the question im asking.

There are vehicles that have a flex fuel sensor that can automatically switched between say a premium 91 octane map and E85 map depending on the amount of ethanol the sensor is reading

 

[Barney556180]

While the owners manual doesn’t specifically say, it does imply the PCM adjusts for the fuel being used.

“Fuel Requirements:
If your vehicle is E-85 compatible, it will operate on unleaded gasoline with any octane rating, or solely E-85 fuel, or any mixture of these fuels.
For best results, avoid fueling patterns alternating between E-85 and unleaded gasoline.

When switching fuel types:
• Add 5 gallons (19 liters) or more when refueling.
• Drive the vehicle immediately after refueling for at least 5 miles (8 km).
Observing these precautions will avoid possible hard start- ing and/or driveability problems during warm up.”

Also from the manual: “Because E-85 fuel contains less energy per gallon/liter than gasoline, an increase in fuel consumption will be experienced. The miles per gallon (mpg)/kilometers per liter and the driving range will decrease by approximately 30%, compared to gasoline operation.”

Based on the average spread of E-85 $2.07) and regular gas ($2.87) in northern Michigan, it’s pretty much a wash as to cost per mile.