Flex fuel

[GOPAPA]

I think I notice that trucks set up for using flex fuel does not bring as much resale value as of a truck that is not set up to use flex fuel

Is there more to go wrong with the injection system with flex fuel ?

[davischevy]

Some people say yes.

The feature can be turned off in the computer.

My wife's new Tahoe has it. When you start it in the garage, it sounds like a 4 cylinder. I can tell when it goes from 4 to 8, but I doubt most people ever notice it.

I have a friend that had his turned off. I personally don't think it helps a lot with fuel mileage.

[95 S_Trucker]

There is an additional fuel composition sensor. I’ve never seen one go bad.

[95 S_Trucker]

Originally Posted by davischevy

Some people say yes.

The feature can be turned off in the computer.

My wife's new Tahoe has it. When you start it in the garage, it sounds like a 4 cylinder. I can tell when it goes from 4 to 8, but I doubt most people ever notice it.

I have a friend that had his turned off. I personally don't think it helps a lot with fuel mileage.

I think you are mixing up flex fuel with active fuel management.

[davischevy]

Originally Posted by 95 S_Trucker

I think you are mixing up flex fuel with active fuel management.

I sure did it easily though didn't I?

In my case, it's better to keep my mouth shut, and appear stupid, than to open it and remove all doubt.

[Boog]

Sunday Sam’s Garage guy showed a cable and sensor he said was required to use higher levels of ethanol like E85. I just assumed a flex fuel vehicle would have all the equipment it needs from the factory. Is that not the case?

[GOPAPA]

Interesting guys what you came up with,, Computer and flex go together I am getting from you all..

There is a Chevy Silverado 4 door 1500 for sale and it has 82 k miles and they want $19,999 for it .. good looker too,, I am not wanting it but thought it was a good buy and thats why I ask about the flex fuel and I bet thats why it is cheaper that ones do not use flex fuel ... by the way I have not seen 85 % corn oil at the pumps around here.. I think it was 2014

[davischevy]

Larry, do you still have your Duramax? I drove mine to Florida last week and got a solid 22 MPG.

[Boog]

I want one of those. I just don't want the high cost of repairs when it has to have them..

[davischevy]

Originally Posted by Boog

I want one of those. I just don't want the high cost of repairs when it has to have them..

No repairs needed Boog.

Seriously, mine is an LLY engine. They had a problem with heads and head gaskets. Mine had the head warrantied at about 99,000 miles. It had a tuner on it from new. I don't know if that had anything to do with it but we tossed it at that point.

It now has a little over 250,000 on it and I have not had any problems since.

[Boog]

It has served you well but I know you have a great maintenance program for all your vehicles. That's key right there.
Well getting back to flex fuel trucks. Our Yukon is an FF truck but I have no desire to run E85. I don't think it's even available around here anyway. And if I have to buy some additional equipment to even use E85 I'm not interested. Regular unleaded is available every where I go.

[GOPAPA]

Sold the Duramax and the travel trailer Larry .. The wife was real bad a year ago and we decided to give up camping on the Snake River parks we have here.. Now she is on better meds and now thinking maybe buy a 1/2 ton Chevy with a Lance 1685 trailer and do it again ,,only this time ,,go small


I assume from your post Boog that even that you have a flex fuel Yukon ,,it doesn't give you any problems only running regular unleaded and never using any 85 in it..

My daughter had 07 Yukon and it would go brain dead and drop to about 20 miles and hour where ever she was and she would have to pull off the free way and wait a bit for it to get over it's computer problem before she could go again ,,I had a machanic look it over and he could not fix it .,,even after the sum of $500 . then I read up on the internet about the problems Chevrolet was having and the company would do nothing about it. traded it in and thats how we fixed the problem...

I do not know the year of Yukon you have ,,but will ask , have you had this problem with yours?

[68Gold/white]

A non E85 engine has a boat load of sensors and doo-dads just to keep it running as it should. I can't see where the E85 engine would be a whole lot different. If anything the E85 engine is likely to have components in it that would allow the engine to last longer. Like better valves, pistons and valve seats....

I'm no expert here, but I would prefer a non E85 engine also. I have no need for E85.

[GOPAPA]

Well , here is the truck I am looking at (so far just on Craigs List that is ) and it says it is a flex fuel truck .. check it out on Boise Idaho Craigs List ,,

2012 GMC Sierra 1500 Crew Cab SLE Pickup 4D 5 3/4 ft $20,000

[Boog]

Larry no I’ve not experienced anything like that with our 09 Yukon. Worst thing so far was a bad brake light switch that caused a multitude of warnings to pop up. We’re not big on ethanol fuels down here so we don’t go looking for it. Our low and mid grade gas can contain up to 10% ethanol. Premium is said to be E free. I generally use premium in my lawn cutting equipment. May not be necessary but it won’t hurt them.

The truck you are looking at sounds like my 06 GMC crew cab. I pull my 28’ 5th wheel camper with it just fine. 5.3, 4wd, 4.10 gear averages 15.5 mpg around town daily.

[68C15]

Originally Posted by 68Gold/white

A non E85 engine has a boat load of sensors and doo-dads just to keep it running as it should. I can't see where the E85 engine would be a whole lot different. If anything the E85 engine is likely to have components in it that would allow the engine to last longer. Like better valves, pistons and valve seats....

I'm no expert here, but I would prefer a non E85 engine also. I have no need for E85.

Mechanicals and sensors are the same. Just programming. It uses the oxygen sensors to determine alcohol content after a fueling event, no more composition sensors. At most an E85 engine would have higher flow injectors, but I don't see them wasting the money to have separate ones for each.

[Greenlee]

I’ve got a 2012 Yukon Denali. You guys are making me wonder if it’s flex fuel. I’m kind of embarrassed to say that I have no idea. It’s been a great truck. It has about 89,000 miles on it. It’s got the 6.2 with active fuel management. No problems so far. According to the computer it averages 15.1 mile per gallon.

[68Gold/white]

Originally Posted by Greenlee

I’ve got a 2012 Yukon Denali. You guys are making me wonder if it’s flex fuel. I’m kind of embarrassed to say that I have no idea. It’s been a great truck. It has about 89,000 miles on it. It’s got the 6.2 with active fuel management. No problems so far. According to the computer it averages 15.1 mile per gallon.

LOL, if you are not kidding............There's emblems on the outside of your Denali tell the world it can run on corn liquor!!!

[davischevy]

One of my daughters drives a 2012 Suburban, and it says Flex Fuel on the hatch. To my knowledge it has never had more than 10% Ethanol in it.

[kenn]

Hello, I have a 2012 Silverado with a 4.8 flex eng in it. I bought it used at the dealer for a "good" price. It took me 8 months and 3 trips at $350 each to learn how to put fuel in it. The sensors that determine what type of fuel goes into the tank have changed a few times over the years. In my truck I have to fuel up "after" the eng has warmed up to temp for 10min. After fueling up I can not turn it off for 10 miles or the computer defaults to E85. The dealership got this info from the tech at Chevy he called. The computer controls how the eng runs and if it thinks it has E85 and actually has reg unleaded it runs like cr-p.
K.E.N.

[Axle]

I guess here is where ford shines a bit, my 2008 flex fuel ford determines fuel type via programming and monitoring th o2 sensors (among other things) anytime the vehicle is refueled the computer prioritizes "checks" on o2 (etc) and adjusts the fuel map and spark timing based on what it sees. No special fuel sensors needed.

[GOPAPA]

Originally Posted by kenn

Hello, I have a 2012 Silverado with a 4.8 flex eng in it. I bought it used at the dealer for a "good" price. It took me 8 months and 3 trips at $350 each to learn how to put fuel in it. The sensors that determine what type of fuel goes into the tank have changed a few times over the years. In my truck I have to fuel up "after" the eng has warmed up to temp for 10min. After fueling up I can not turn it off for 10 miles or the computer defaults to E85. The dealership got this info from the tech at Chevy he called. The computer controls how the eng runs and if it thinks it has E85 and actually has reg unleaded it runs like cr-p.
K.E.N.

Originally Posted by Axle

I guess here is where ford shines a bit, my 2008 flex fuel ford determines fuel type via programming and monitoring th o2 sensors (among other things) anytime the vehicle is refueled the computer prioritizes "checks" on o2 (etc) and adjusts the fuel map and spark timing based on what it sees. No special fuel sensors needed.

Both of these replys are worth a lot ,,as each tell a story of their own .. thx guys ,,I copied these for further reference and until I am satisfied much more than I am rigtht now ,,I do not plan to buy a Flex Fuel truck ,,seems like just more things to go wrong in the brain of the computer.. might be wrong ,,but until I am proven I am not taking a big chance with the Flex Fuel ,,when I would never use any,,??,,I'll wait awhile and see.

[kenn]

Hello, Two more things. After I learned how to put fuel in it I have not had any problems with it. I drive 50 miles highway to work and get 17gpm summer and 16 in winter.
They don't have E85 in CT.
Basically what happens is the comp reads how much fuel you just put in the truck EX 10 gal to a 30 gal tank. The comp reads the type of fuel and adjusts the percent of alcohol for the 30gal. If fueled correctly the percentage will stay below 10% (here in CT) and the truck runs fine. What was happening to me was the comp was defaulting because I was not giving the comp time to figure all the stuff it had to figure. So the fuel I was adding (10gal) was at 85% added to a tank of 20gal of 10%. After a few top offs the truck starts to run bad. I was topping off just before I was getting home or just after leaving.The dealer says the truck thinks I have 55% alcohol in it. They fix the comp and after the third time I learn from them how to put fuel in it and its ok now.
Sorry so long but I hope it helps. K.E.N.

[GOPAPA]

Originally Posted by kenn

Hello, Two more things. After I learned how to put fuel in it I have not had any problems with it. I drive 50 miles highway to work and get 17gpm summer and 16 in winter.
They don't have E85 in CT.
Basically what happens is the comp reads how much fuel you just put in the truck EX 10 gal to a 30 gal tank. The comp reads the type of fuel and adjusts the percent of alcohol for the 30gal. If fueled correctly the percentage will stay below 10% (here in CT) and the truck runs fine. What was happening to me was the comp was defaulting because I was not giving the comp time to figure all the stuff it had to figure. So the fuel I was adding (10gal) was at 85% added to a tank of 20gal of 10%. After a few top offs the truck starts to run bad. I was topping off just before I was getting home or just after leaving.The dealer says the truck thinks I have 55% alcohol in it. They fix the comp and after the third time I learn from them how to put fuel in it and its ok now.
Sorry so long but I hope it helps. K.E.N.

You have done good Kenn .. long is better in explaining what happened and how you fixed the problem.. I now know somehing I knew very little about,, thank you

[Axle]

Attached is the ford summary on how it determines alcohol content.

Alex.