What Is The Diff Between '08 Flex Fuel And Gas Only 5.3l?

sshoureas · November 9, 2007

I ordered my new 08 All Terrain and was disappointed to find that the Flex Fuel 5.3 is on restriction and cannot currently be ordered. Could the gas only engine be easily (and inexpensively) modified IF E85 becomes readily available and less expensive than gas ? As this is a NO COST option I'm disappointed I can't order it. Anyone know what the differences are ?

Import Hater · November 9, 2007

This is not something you'd want to modify. A new PCM and fuel pump assembly for sure. Probably fuel lines, injectors, a different EVAP system, maybe even a fuel tank too. Thousands and thousands of dollars...all to save NOTHING!

Yes E85 gas is cheaper. But did you know that is less efficent than regular gasoline? Figure on seeing the miles per gallon drop by 20% using E85, which will certainly offset the savings of how much the stuff costs at the pump. E85 is really only for the folks concerned with preserving the envionment.

Heysdad · November 9, 2007

I ordered my new 08 All Terrain and was disappointed to find that the Flex Fuel 5.3 is on restriction and cannot currently be ordered. Could the gas only engine be easily (and inexpensively) modified IF E85 becomes readily available and less expensive than gas ? As this is a NO COST option I'm disappointed I can't order it. Anyone know what the differences are ?

I just ordered my 2008 Z-71 last week with a PBD of 11/18/07 and had no problem getting a FlexFuel 5.3. Who told you about a restriction? Why would it be restricted???

sulman · November 9, 2007

I ordered my new 08 All Terrain and was disappointed to find that the Flex Fuel 5.3 is on restriction and cannot currently be ordered...

Any idea why the FF engine is on restriction??

MS3DALE · November 9, 2007

I ordered my new 08 All Terrain and was disappointed to find that the Flex Fuel 5.3 is on restriction and cannot currently be ordered. Could the gas only engine be easily (and inexpensively) modified IF E85 becomes readily available and less expensive than gas ?

No,I wouldn't even want to think what it would cost to convert it/change it over to make it E85 capatible.

I'd have to check in the parts catalog to make sure but I know the fuel rails and most of the fuel lines are different,also there are sensor/sensors that would need to be added,and the PCM/BCM would need reprogrammed.

Heres a bulletin from GM on this very subject.....

Document ID# 2000881

Subject: Usage of E85 Fuels in GM Vehicles #05-06-04-035C - (07/30/2007)

Models: 1997-2008 GM Passenger Cars and Trucks (including Saturn)

2003-2008 HUMMER H2

2006-2008 HUMMER H3

1997-2008 Isuzu NPR Commercial Medium Duty Trucks

2005-2008 Saab 9-7X

This bulletin is being revised to add the 2008 model year and additional engines with E85 capability. Please discard Corporate Bulletin Number 05-06-04-035B (Section 06 -- Engine/Propulsion System).

Customer Interest in E85 Fuel:

As the retail price of gasoline increases, some locations in the country are seeing price differentials between regular gasoline and E85 where E85 is selling for substantially less than regular grade gasoline. One result of this is that some customers have inquired if they are able to use E85 fuel in non-E85 compatible vehicles.

Important: Only vehicles designated for use with E85 should use E85 blended fuel.

E85 compatibility is designated for vehicles that are certified to run on up to 85% ethanol and 15% gasoline. All other gasoline engines are designed to run on fuel that contains no more than 10% ethanol.

Notice: Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

Using E85 Fuels in Non-Compatible Vehicles

General Motors is aware of an increased number of cases where customers have fueled non-FlexFuel designated vehicles with E85. Fueling non-FlexFuel designated vehicles with E85, or with fuels where the concentration of ethanol exceeds the ASTM specification of 10%, will result in one or more of the following conditions:

• Lean Driveability concerns such as hesitations, sags and / or possible stalling.

• SES lights due to OBD codes.

• Fuel Trim codes P0171 and / or P0174.

• Misfire codes (P0300).

• Various O2 sensor codes.

• Disabled traction control or Stability System disabled messages.

• Harsh / Firm transmission shifts.

• Fuel system and / or engine mechanical component degradation.

Notice: Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

If the dealer suspects that a non-FlexFuel designated vehicle brought in for service has been fueled with E85, the fuel in the vehicle's tank should be checked for alcohol content with tool J 44175. If the alcohol content exceeds 10% , the fuel should be drained and the vehicle refilled with gasoline - preferably one of the Top Tier brands.

Repairs to non-FlexFuel vehicles that have been fueled with E85 are not covered under the terms of the New Vehicle Warranty.

A complete list of GM’s FlexFuel vehicles can be found in this Service Bulletin, or at www.livegreengoyellow.com.

E85 Compatible Vehicles

The only E85 compatible vehicles produced by General Motors are:

• 2000-2002 S-Series pickups with 2.2L (VIN 5- RPO L43)

• 2002-2005 full-size pickups and utilities with 5.3L (VIN Z -- L59)

• 2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe with 5.3L (VIN Z -- RPO L59)

• 2006-2007 Chevrolet Impala, Monte Carlo with 3.5L (VIN K -- RPO LZE)

• 2007 Chevrolet Avalanche, Suburban, Tahoe with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

• 2007 Chevrolet Express, GMC Savana with 5.3L (VIN Z-- RPO L59)

• 2008 Chevrolet Impala with 3.9L (VIN 3-- RPO LZG)

• 2006 GMC Sierra, Yukon, Yukon XL with 5.3L (VIN Z -- RPO L59)

• 2007 GMC Yukon, Yukon XL with 5.3L (VINs 0, 3 -- RPOs LMG, LC9)

• 2007 Saturn Relay, Buick Terraza, Chevrolet Uplander, Pontiac Montana SV6 (Canada Only) with 3.9L (VIN W -- RPO LGD)

Notice:

• Only vehicles that are listed in the E85 Compatible Vehicles section of this bulletin and/or www.livegreengoyellow.com are E85 compatible.

• All other gasoline and diesel engines are NOT E85 compatible.

• Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

• Repairs to non-FlexFuel vehicles that have been fueled with E85 are not covered under the terms of the New Vehicle Warranty.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

Document ID# 2000881

sshoureas · November 9, 2007

I ordered my new 08 All Terrain and was disappointed to find that the Flex Fuel 5.3 is on restriction and cannot currently be ordered. Could the gas only engine be easily (and inexpensively) modified IF E85 becomes readily available and less expensive than gas ? As this is a NO COST option I'm disappointed I can't order it. Anyone know what the differences are ?

I just ordered my 2008 Z-71 last week with a PBD of 11/18/07 and had no problem getting a FlexFuel 5.3. Who told you about a restriction? Why would it be restricted???

The dealer told me it was on restriction and I saw the big red "X" next to the FF option. Could it be a regional thing or possibly due to mty particular configuration ?

mcreyaufmiller · November 9, 2007

E-85 is a fad. As a country we cannot sustain the producton of a fuel from a food supply. The other problem, well it takes more energy to produce E-85 than we save by using it.

pm26 · November 9, 2007

E-85 is a fad. As a country we cannot sustain the producton of a fuel from a food supply. The other problem, well it takes more energy to produce E-85 than we save by using it.

No, E85 is not a fad. Driving monstrous SUVs and full size trucks where an economy car would suffice is.

DanMan_S · November 9, 2007

E-85 is a fad. As a country we cannot sustain the producton of a fuel from a food supply. The other problem, well it takes more energy to produce E-85 than we save by using it.

No, E85 is not a fad. Driving monstrous SUVs and full size trucks where an economy car would suffice is.

No, he's right. The production requirements to make E85 are huge, they will destroy NA agriculture. As well, the crops that E85 is made from are the ones farmers want to keep cheap because they use them for feed for livestock. We'll keep driving big trucks but a better fuel alternative will have to be introduced soon.

Oh, and E85 is sorta better because of the fact that it has a lower heating value. Why? It behaves the same as a higher octane gas, thus you can crank up the engine compression. Alot of hot rodders are jumping on the E85 bandwagon simply because they can build the engine to run higher compression without having to switch to higher and higher octane fuels.

redvett · November 9, 2007

I agree with PM26 and add driving at high speeds (speeding) oversized tires,too large high horsepowered engines etc. Are fads and it wont be to many years everone will be driving small economy vehicles like Europe does. Remember $4 gas will be here in 2008.

NathanL · November 9, 2007

I agree with PM26 and add driving at high speeds (speeding) oversized tires,too large high horsepowered engines etc. Are fads and it wont be to many years everone will be driving small economy vehicles like Europe does. Remember $4 gas will be here in 2008.

Gas is 0.50 a gallon higher than it was last year...and demand/usage is still up 3%.

Gas is double what it was 4 years ago and demand/usage still grows every year.

Maybe at some point we say people drive more economy related vehicles en mass here in the US. But we haven't reached that yet. Every time we set the threshold higher we blow thru it and keep buying more and more gasoline. It used to be when gas hit a $1/gallon or $2/gallon. I remember in the mid 90's they had hearings in congress at the urging of President Clinton about how we were being gouged at $1.35 a gallon and if it was to reach $1.50 it would cripple the US economy......

Everytime I see someone pushing a hybrid car or electric car on TV I go drive me other car for a while just to get out of the house - getting 4.5mpg just for the hell of it.

sulman · November 9, 2007

Back to the question, please...Why is the FF engine restricted?

MS3DALE · November 9, 2007

Back to the question, please...Why is the FF engine restricted?

They don't tell us dealers why something is on restriction,It could be a number of reasons,The main one being a shortage of parts.

When I was ordering my '07 I wanted the optional 730 CCA HD battery,It was on restriction,we thought the reason was that GM needed them for the Duramax's,but we never could get a definite answer. (Plus the HD battery is now an "SEO" option which sometimes can be harder to get)

sulman · November 9, 2007

They don't tell us dealers why something is on restriction,It could be a number of reasons,The main one being a shortage of parts.

I see. Thanks. I was planning to order an 08 Sierra FFV. Sounds like I'll need to locate the right vehicle instead. My local dealer has almost the truck I would order. I guess I'll wait until mid-month to see what happens to the incentives. I'm hoping GM will sweeten the pot a bit.

hubbycap · November 9, 2007

E-85 is a fad. As a country we cannot sustain the producton of a fuel from a food supply. The other problem, well it takes more energy to produce E-85 than we save by using it.

No, E85 is not a fad. Driving monstrous SUVs and full size trucks where an economy car would suffice is.

E85 IS a fad. But if it is rammed down our throats by the tree huggers it doesn't matter, like R134a. And what do we get for our corn production being high-jacked to our gas tanks? Well, we get $10/lb hamburger, $40/fifth liquor, and $5/doz eggs. Corn ain't free, and you can't make tortillas out of crude. E85 still burns and produces CO2.