So here is my predicament... I'm a salesman at a Chevrolet store and there's a customer that came in and he drives a 5.3 Silverado. He went to a local shop and the mechanic hooked his truck up to the computer and turned off his Flex Fuel. He has an app on his iPhone that calculates fuel mileage and since he got that done he has gained at least 3mpg. Also his tailpipe has ZERO black junk on it anymore. Seems completely smart to find someone to do this on my 07 F150. With 24" wheels I would like to get all the mileage I can.

 

Fords flex fuel only consist of seals that can handle ethanol, gms flex fuel is the same thing. But the motors have cylinder deactivation. Which is what I'm thinking you mean. Fords don't do that.

 

lol

flex fuel capability is comprised of physical parts in the engine, not a pcm/ecu function.

if you are a chevrolet salesman at a chevrolet store, why not go in the back and ask a tech? or will they just laugh at you?

 

You can laugh all you want like a douchebag ******* but i'm just bringing up what he said. I didn't know if there was something involved with the computer and maybe you don't either so don't reply just to be an ***. I talked to one of the other guys here and they said there IS a flex fuel related setting in the ECU that gives the the truck more fuel than it can burn and thats why the tailpipe is always black.

 

No man, there isn't. But it's whatever.

 

Haha and you're a salesman?

 

there's no need to start calling people names, if you don't like a comment someone makes, ignore it.

I did some quick google-ing to see what I could find about "turning off" flex fuel on a silverado and AFM is more likely what they messed with.

What eveyone said is probably true, most likely they disabled the AFM (active fuel management) on his silverado. (I assume you know what this is since you work at a chevy dealership). The ability to run E85 (flex fuel vehicles) on F150's at least, is a change in hardware, new gaskets and such that can withstand the ethanol without breaking down. The computer adjust timing and such just the same way it does with different grades of fuel, by monitoring the O2 sensors and such to adjust lean/rich. There is no "special" program in the pcm to run E85, so it most likely cannot be "turned off" on your f150.

Without knowing exactly what they did to the silverado there's no real way to decide if it can be done to the F150's.

 

i think i summed this up here:

And in regards to:

This has nothing to do with Flex Fuel and everything to do with your Air/Fuel Ratio. You would need a Wideband o2 Sensor to get an accurate reading.

Active Fuel Management is only the ability to turn off half of your cylinders via a PCM/ECU function, thus non related to Flex Fuel as well.

 

thanks pcwiz. makes sense i was just wonderin if there was something about it i didn't know. The active fuel management pretty much never turns on with normal people's driving. I knew about the hardware that needed to be changed for the flex fuel but wasn't exactly sure if thats what they would've changed on his truck but i guess it might've just been a chev thing. Thnks

 

Troyer told me that there is a sensor which detects how much alcohol is in the fuel mix and adjusts the tune for it automatically. No way to turn it off, though.