Which 5.3l Is Flex Fuel?

[HotRodV6]

O just bought an 03 silverado with the 5.3L "T" engine and wanted to see if mine was flex fuel or not? If so E85 si about 30 cents cheaper a gallon here and i want to try it out and see how the truck runs on it.

[Draenor]

It should say flex fuel or E85 somewhere if it does, like the gas cap. If anything look for a L59 RPO code on the glove box.

[sshoureas]

If it is only 30 cents/gallon cheaper don't bother. E85 delivers as much as 20% lower milage than gasoline so the price differential needs to be greater to make it worthwhile.

[Lances07Z71]

I'm not 100% sure but I don't think they made a Flex fuel engine in 03.

[neonhomer]

Another question would be what does it take to convert the regular `04 5.3 to FlexFuel..... We don't have it in Florida yet, but would like to convert to use it when we get it....

 

BTW - My engine is the LM7.....

[HotRodV6]

I thought 03 was the first year they were available, but not sure, and mine is the LM7 also, not the L59.

 

 

I really think if you want to convert to E85, you need to get bigger injectors and the PCM tuned to run E85. Other than that there isnt alot of parts that need replaced. Some will say the fuel pump module needs replaced but ive heard of some running the stock one. Also the fuel rails are all stainless, and all fuel lines are compatible.

[MS3DALE]

Theres a lot more to it than injectors and a PCM tune,And all fuel lines ARE NOT compatible,Believe me I can name a few guys who thought they could run E85 with little modifications,A couple thousand dollars later at our dealership they were back on the road with there "non-E85" vehicles!!

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

 

 

 

Document ID# 1847183

 

 

Subject: Use of E85 Fuels in Vehicles Not Certified As Being FlexFuel Compatible/Aftermarket Conversion of Vehicles to Operate on E85 Fuels #06-06-04-035 - (07/13/2006)

 

 

 

Models:

2007 and Prior GM Passenger Cars and Trucks NOT FlexFuel (E85) Compatible (including Saturn)

 

2007 and Prior HUMMER H2, H3

 

2005-2007 Saab 9-7X

 

Aftermarket Conversions of Vehicles to Use E85 Fuels

General Motors has become aware of several companies that claim to be able to convert vehicles equipped with gasoline engines to be compatible with E85 Fuels.

 

• Vehicles certified by GM as being FlexFuel (E85) compatible contain numerous calibration and component differences that are not conducive to an aftermarket retrofit.

 

• General Motors DOES NOT support or endorse conversions that may alter the emissions and related emissions components of its vehicles.

 

• Repairs that may result from changes to GM built components, and repairs that result from the use of improper fuel, such as the use of gasoline containing more than 10% Ethanol in a non-FlexFuel certified vehicle, are not covered under the terms of the New Vehicle Warranty.

 

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

 

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

 

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

 

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

 

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

 

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

 

 

 

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

 

 

© Copyright General Motors Corporation. All Rights Reserved.

Document ID# 1847183

[MS3DALE]

If it is only 30 cents/gallon cheaper don't bother. E85 delivers as much as 20% lower milage than gasoline so the price differential needs to be greater to make it worthwhile.

Nope,Actually it needs to be 20 to 30 cents cheaper to "break even" cost wise with regular gasoline.

So if its 30 cents cheaper you'd be OK.

[neonhomer]

So, GM is saying that they don't support it.... but it doesn't mean it can be done.

 

So far, we have injectors, PCM, fuel lines, and fuel pump module....... I would also say there is some kind of fuel detection sensor to tell the PCM when to use E85 settings and when to use "pure" gas settings. I would think the motor itself would be the same.

 

I think this is going to be a costly venture, and the likelihood of Florida having widely available E85 anytime soon is very slim...

[MS3DALE]

I would also say there is some kind of fuel detection sensor to tell the PCM when to use E85 settings and when to use "pure" gas settings. I would think the motor itself would be the same.

 

Yes,There is a sensor for this.

And the engines,internally,are the same.

[sagent]

I believe the owners manual states if outside temp less than 32 degrees F

E85 should be mixed 50%-50% gasonline in order for the vehicle to start in cold climates.

[norsemanberg]

I would also say there is some kind of fuel detection sensor to tell the PCM when to use E85 settings and when to use "pure" gas settings. I would think the motor itself would be the same.

 

Yes,There is a sensor for this.

And the engines,internally,are the same.

 

 

 

 

So what do they call that sensor?

[outlawfab]

if you have that pain in the @$$ fuel filter to change like on my tahoe it is flex fuel. 02 vin "z"

[YUKop]

I have an '04 yukon 5.3 that can use E-85, eighth character in VIN has to be "Z", check owners manuel also

[slimjim2525]

So, GM is saying that they don't support it.... but it doesn't mean it can be done.

 

So far, we have injectors, PCM, fuel lines, and fuel pump module....... I would also say there is some kind of fuel detection sensor to tell the PCM when to use E85 settings and when to use "pure" gas settings. I would think the motor itself would be the same.

 

I think this is going to be a costly venture, and the likelihood of Florida having widely available E85 anytime soon is very slim...

You do not have an e-85 compatable vehicle, and do not use e-85. Ethanol is much more corrosive than gasoline, and you will be looking at serious problems in the future. There are NO conversion kits to make it a flex fuel vehicle. If you want a flex fuel vehicle, then go buy one, don't think you can turn this truck into one.