Dealer conversion of the 5.3 L to the 5.3 L Flex Fuel E85

jkachjkach Member Posts: 3
edited April 2014 in Chevrolet
I have asked several GM service managers and can't get the same answer. (some say its a reprogram of the computer - gas cap and decal, others say its a replacement of the fuel rails - fuel pump - and reprogram - and still others advise that it can't be done). I have spent several hours on the phone with GM tech and can't get an answer / they just refer you back to the dealer’s service manager. So, my question, I am in the process of purchasing a new 2008 GM with a 5.3L motor. What is involved in having the GM dealer convert the 5.3L motor to a 5.3L – Flex Fuel E85 ??


  • ahightowerahightower TXMember Posts: 539
    I'm not much help, but just wondering why not buy an E85 to begin with?
  • kiawahkiawah Member Posts: 3,666
    I'm w/hightower......if you want the flex fuel, just buy a model that already is. Why would anyone want to take a brand new vehicle, and then have the dealer (or anybody).....go in and start messing with something as critical as fuel delivery?

    Secondly, not sure the real value of flex fuel anyhow. My Suburban has flex fuel, but I've never even seen a gas station w/flex fuel. I've also heard that the performance and fuel consumption is horrible, as the 'fuel' has less power/energy. Personally, this is not something that I have seen any value in having.
  • jkachjkach Member Posts: 3
    The vehicle that I want (color and options) and that is currently in stock - is not Flex Fuel E85.
  • kiawahkiawah Member Posts: 3,666
    If flexfuel capability is important to you, keep shopping. If you were considering even paying for a flexfuel upgrade, you could justify upbuying to a higher level trim that already has flexfuel engine.
  • arriearrie Member Posts: 312
    Converting a non FlexFuel engine to FlexFuel might not be that simple.

    The problem is that some seals like intake manifold seal at least used to be of different material for FlexFuel engines as alcohol corrodes materials differently than pure gasoline. I don't think intake manifold seal really is a problem as it sees very little of the fuel but GM used to have different seals for this, i.e. orange color for normal and green color seal for FlexFuel engines.

    But there could be a big problem to fix if you would want to convert the engine: The fuel type sensor that at least older vehicles have.

    FlexFuel vehicles have a fuel type sensor (yes, I have FlexFuel engine in my '04 Tahoe. Sensor is located on driver side under the car at about half way) that obviously senses if you run pure gasoline or E85. The sensor tells the PCM which fuel you run with, which allows adjustment for ignition timing. These fuels have different compression / burning characteristics and ignition timing must be adjusted accordingly.

    The fuel sensor has to have wiring for it, which could be there even if the car is without the sensor but I think there is no pre-wiring. In any case it would take at least re-programming the PCM but probably a new PCM and wiring for fuel sensor to do it.

    There is a chance that a new FlexFuel cars do not use fuel sensor any more and for fuel sensing they use 02 sensors. I don't know if GM is that far yet. Someone with a new FlexFuel vehicle could crawl under the car and see if there is a sensor or not. (Any volunteers?) If the Fuel sensor is not used any more then it should only take re-programming the PCM and perhaps replacing 02 sensors.

    I would recommend you not to even think about conversion later on. If you want FlexFuel you need to buy one built with it. And waiting for FlexFuel might be good for future as E85 might be more available. I have driven two tank fulls with E85 and it does give about 15 % less MPG but it runs cleaner and who knows it might be the fuel more available in the future than pure gasoline. I would use more E85 but it is not available in my area. I can buy it only if I travel about 350 miles out from my home.

    It is just amazing how little GM dealer shops know about the vehicles they sell as they have not been able to tell if conversion is possible. But what can you expect from a company which is going under anyway.

  • jkachjkach Member Posts: 3
    Arrie ~ Thank your for taking the time to answer my question and provide helpful information. I really appreciate your response !!
  • flip08flip08 Member Posts: 8
    I have a Chevy Suburban that needs a new fuel line (and possibly fuel tank) along with a new muffler system. Otherwise its in great shape. I will miss it for it's cargo hauling ability and was about ready to donate it but thought I'd ask and see if anyone has been able to convert a suburban beast into an alternative hybrid of somesort.
  • whitey1940whitey1940 Member Posts: 2
    I have a 2006 Suburban 5.3 L but it is not flex fuel. I also spend my winters in Florida and down there regular gas is almost non-existent, everything is "up to 10 % ethanol". Using the ethanol fuel, I found no difference in power or engine operation, however I did lose about 2-3 mpg (Cdn). I would consider trading for a flex fuel because I simply do not know what the results will be after using ethanol fuel for about 7500 km's per year. While here in Ontario I am hoping I can still find regular unleaded fuel without the 10% ethanol. The owners manual states "Do Not Use the Ethanol Fuel", of course I do not have any choice when in the south. I do use Duralube every 20,000 Km's. The vehicle only has 80,000 km's on it and all is absolutely perfect with it, I just wish there was a guru out there that could tell me what kind of damage to expect. I am assuming that an intake manifold gasket would be likely as one of my service people tell they do replace a fair number of them in the 5.3 L Vortex. I notice the price of the 2008 and 2009 used Burbs has increased dramatically over the last few months.
  • kiawahkiawah Member Posts: 3,666
    I think you may be confused.

    A regular engine, can run up to 10% ethanol with no problem, which seems to be fairly standard availability.

    An E85 flex fuel engine, is made to handle gas that is up to 85% ethanol.

    I've only ever seen 1 station in my area that even sells 85% ethanol fuel, and as I understand the mpg is extremely poor.

    If your stations have 10% ethanol, that's fine for your current burb.
  • suburban68suburban68 Member Posts: 3
    Hi all. I own a '00 (gmt830) Suburban that has been equipped with an aftermarket E85 kit. Runs fine, more silent at idle, sounds greater at 2500-3500 rpm and more power when running on Ethanol. Kit was installed by the owner before me. Running on Ethanol with this 5.3litre is genius!
    Olivier (France) :)
  • whitey1940whitey1940 Member Posts: 2
    I thank you so much for that information, as I said I needed a guru and there you were. No need to get excited about trading for a 2009 unless of course my good wife says I should anyway............... Once again thanks for your comeback, it truly is a "peace of mind" to me.

    I have not seen any 85% ethanol stations and we have lots of regular unleaded gas outlets here in Ontario.

    Have a good day.
  • suburban68suburban68 Member Posts: 3
    just a word about consumption and co2 emissions

    If regular unleaded gives 100% CO2, 5% ethanol gives 97% CO2, 85% ethanol gives 25% CO2. Cleaner! source:

    About consumption, no noticeable difference between regular unleaded (I can buy some in the very near Switzerland) and 5% ethanol which is the standard unleaded distributed in France. When you play with 85%, big change. As Ethanol gives a poor burning in the engine (about 20% difference), injection system reacts to obtain stoechiometric mix, to have the best explosion in the cylinder. You then can see consumption change from 20%. My 'burb goes from 16 litres p. 100 km to 19... calculate, that's 20% difference...
    Regarding prices (and in France it's sooooooooo high), E85 is cheaper than regular unleaded (0.85 Euro vs 1.16 Euro per litre/ 1.16 USD vs 1.59 USD / 1.35 CAD vs 1.84 CAD ). About 20% today, few months ago it was really worthy to run Ethanol because the gap was higher.
    And remember, you can run up to 10% Ethanol with no mods on the engine.
    I own an old beast ('92 Ford Explorer, V6, 4.0 litre) than runs a home-mix of 50% unleaded 50% E85. Funny, powerful, cleaner, despite its 314.000 km (about 198.000 mi)
    Yes, Ethanol can be adapted to most engines
    Even if no FI system and no CAT, running on Ethanol may require a timing setting, that's all.
    Don't forget the first car running on Ethanol (in this time, it was called 'alcohol') was a car called Ford Model T... :)
This discussion has been closed.