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Thread: E38 Flex Fuel: On the fly timing and fueling - anyone interested?

  1. #31
    Lifetime Member GMPX's Avatar
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    You do have the option that will cost you about $5 and an hour of your time.
    Read THIS pdf, you can set the ECM up to switch between 0% and 85% ethanol, whilst not flexible like the sensor you can at least run two tunes.
    I no longer monitor the forum, please either post your question or create a support ticket.

  2. #32
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    The early systems used the Hard Wired E85 Sensor correct ? So the fake square wave module could
    also be used on those systems correct ? eg. LS1B 1024K PCM

  3. #33
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    Quote Originally Posted by L31Sleeper View Post
    The early systems used the Hard Wired E85 Sensor correct ? So the fake square wave module could
    also be used on those systems correct ? eg. LS1B 1024K PCM
    That's what this thread points to but is not all that explicit. Apologies... The references to using i.e. an AVR micro or something similar is in reference to using the a square wave to set ethanol content . It can also be used to alter fueling and/or timing on the go - like from the dash, if the stoich value is set to a constant via EFILive tuning.

    For some reason, GM has elected to go with hard sensors on the MY11 Commodores in Australia, vs their patented Virtual Fuel Sensing system.

  4. #34
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    Quote Originally Posted by GMPX View Post
    Aside from that, E85 prices are as expected a joke here in Australia (only a max of 20 cents per/L cheaper), I can't see it being worth your while if you have no other reason other than wanting to run E85 out of curiosity.
    Ain't that the truth! Given E85 uses around 50% more fuel at stoich than petrol/gas it would need to be ~40% lower in price than regular unleaded to be worth the effort. With the pricing the petrol companies are using to sell E85 at, it increases fuel costs considerably. Message: we dont really want to sell you E85 because it is too hard, and we have petrol (gas) which we are making stunning profits on so why bother with anything else .

  5. #35
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    The E85 Custom OS for the E38 is cool since it has just about every other feature you could
    possibly need. But it is a On/Off style. It would be cool to DIAL in fuel and/or timing.

    I don't know what an AVR Micro is ??

  6. #36
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    Quote Originally Posted by L31Sleeper View Post
    The E85 Custom OS for the E38 is cool since it has just about every other feature you could
    possibly need. But it is a On/Off style. It would be cool to DIAL in fuel and/or timing.

    I don't know what an AVR Micro is ??
    google "AVR Micro" ...

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    I have a question. Why are we looking to enable the old hard wired composition sensor? Why are we not pursuing enabling the Virtual Composition Sensor that is currently employed in every FFV since 2006? I am confused... That path would seem to be the best path for having a far more robust control system with dynamic adjustment of both fuel and spark based only on the O2 sensor readings.

    My understanding is that once the VCM detects a change in the fuel in the vehicle of 5 gallons or more, the Virtual Function is enabled in an FFV VCM. What is the difference between the FFV VCM and the non FFV VCM. Are these completely difference OS's or is it just a flag?

  8. #38
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    Because some applications don't run the fuel level sensor through the ECM so it has no idea when ethanol may have been put in the tank.
    I no longer monitor the forum, please either post your question or create a support ticket.

  9. #39
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    Quote Originally Posted by samgm2 View Post
    I have a question. Why are we looking to enable the old hard wired composition sensor? Why are we not pursuing enabling the Virtual Composition Sensor that is currently employed in every FFV since 2006? I am confused... That path would seem to be the best path for having a far more robust control system with dynamic adjustment of both fuel and spark based only on the O2 sensor readings.

    My understanding is that once the VCM detects a change in the fuel in the vehicle of 5 gallons or more, the Virtual Function is enabled in an FFV VCM. What is the difference between the FFV VCM and the non FFV VCM. Are these completely difference OS's or is it just a flag?
    Two more answers in addition to GMPX Forum Tyhee...esquire... Which is very relevant as the VFS ethanol content measuring sequence does not commence until the tank varies by a present amount.

    1/. GM in various applications still uses the hard sensor. Holden is one of them.

    2/. Getting VFS working on a non factory VFS car has not proven to be a walk in the park. Its much more than a flag. Though a flag can certainly turn if off, it doesnt turn it on. If the VFS tuning is not present in the calibrations due to car/truck not being a VFS model, then the tuning is likely missing. Even with the same OS.

  10. #40
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    I don't think this is true. The fact of the matter is that MOST GM's produced since 2005/2006 use a virtual composition sensor. My understanding from talking to GM Goodwrench mechanics is that the detection takes place when five or more gallons are added to the tank. Moreover, the E37 and E38 computers came out AFTER the conventional composition sensors were discontinued. The use of the old composition sensor with these computers shouldn't be required. These OS's support virtual composition sensors.

    I went out today and purchased a FFV E-37 and I plan to install it into my non FFV Cobalt. If this test works, then it means that the function is 100% software and we simply haven't found how to enable the virtual composition sensor (software utilizing O2 sensor information).

    We need to.

    Quote Originally Posted by GMPX View Post
    Because some applications don't run the fuel level sensor through the ECM so it has no idea when ethanol may have been put in the tank.
    Last edited by samgm2; June 28th, 2011 at 01:09 AM.

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