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Thread: Flex fuel DBC OS

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    Default Flex fuel DBC OS

    Starting to try and figure out how to get flex fuel working using a 512 KB PCM. I have found the couple of L59 OS's over on the Tune Depot, but noticed that those are for a DBW setup. Internet reading says that you could have an L59 in either the truck or SUV. The Tahoe/Yukons were some of the 1st vehicles that got the DBW. I am hoping that maybe a Silverado L59 would still of had the DBC. Does anyone have a copy of an 512 kB L59 OS which still used the DBC? The couple of files which people have shared on this forum have also been DBW. I would prefer to try and keep a DBC setup instead of the DBW.

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    Lifetime Member Chevy366's Avatar
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    Just kind of wondering why DBC versus DBW? You do know that you can adjust the DBW in most tune files to mimic DBC responsiveness?
    Last edited by Chevy366; February 27th, 2015 at 08:50 AM.
    2005 1500 HD , Custom OS3 SD tune .
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    Dinosaurs and Plants gave their lives so that we may drive , long live fossil fuel .

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    Quote Originally Posted by turbo_bu View Post
    ... The Tahoe/Yukons were some of the 1st vehicles that got the DBW. I am hoping that maybe a Silverado L59 would still of had the DBC ...
    With 2002 Flex Fuel trucks (OS12216125) the DBC vs DBW option is not a matter of early vs late production ... it is a function of the Traction Control option. If the truck came with the Traction Control option, then it will be DBW. If the truck did not have Traction Control, then it will be DBC.

    E85 has never been available here ... so I have never given Flex Fuel tuning much attention.

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    Quote Originally Posted by Chevy366 View Post
    Just kind of wondering why DBC versus DBW? You don know that you can adjust the DBW in most tune files to mimic DBC responsiveness?
    Funny you should mention that ...

    In some custom vehicles controlled by a PCM (512 Kb or 1Mb), using a DBW setup would be easier to engineer, and offer "free" Cruise Control. Some people stalwartly push a DBC install (even when it is more work) because they were told DBC is "better" at their local coffee shop by some unknown subject matter "expert".

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    Lifetime Member DURAtotheMAX's Avatar
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    Quote Originally Posted by Taz View Post
    In some custom vehicles controlled by a PCM (512 Kb or 1Mb), using a DBW setup would be easier to engineer, and offer "free" Cruise Control. Some people stalwartly push a DBC install (even when it is more work) because they were told DBC is "better" at their local coffee shop by some unknown subject matter "expert".
    x2! Drive by wire all the way. Who wants to screw around with routing/mounting a throttle cable in a custom swap vehicle? I built a 1968 VW Beetle on a Jeep CJ7 frame with a Gen III 5.3 in the back....DBW was a godsend because I would have needed a 15+ foot long throttle cable to get to the rear mount engine.
    2005 Silverado, CC/SB, 4x4, LT, LILLY/Allison
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    many thanks to Ross and Paul

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    I understand that with DBW you can hook it up without the hassel of a throttle cable or cruise control module, but for some of the swaps that I have done, not having to mess with a TAC and DBW TB have been kinda nice too. Most of the time I end up piecing something together and not having the luxury of a complete take out (PCM, TAC module and matching engine). So, having a DBC setup works pretty nicely. Just need a 0411 PCM and a harness to re-work.

    Taz, thanks for clarifying why it either had a DBW or DBC setup with regards to the traction control. I did not know that, but had heard similar logic with regards to later van OS's.

    Has anyone happened to run across a DBC, L59, from a 512 kB LS1B PCM?

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    If Flex Fuel use is your goal, then the 2003 to 2005 truck components may offer the path of least resistance. In these years the APP (gas pedal) and TAC Module are interchangeable - they don't need to be from the same vehicle. Also there was no "special" Flex Fuel OS - they used the same OS an non-Flex Fuel trucks.

    The APP and TAC (complete with harness) are very easy to remove from the vehicle - and these won't cost much from your local "pick your own part" wrecking yard.

    With a DBC setup, if you wanted Cruise Control in your custom vehicle (many people do), you would have to add a Cruise Control Module - which is essentially a TAC Module with a cable protruding. This cable, and the throttle cable, both get attached to the DBC throttle body. For custom vehicles equipped with Cruise Control, DBW is far more user friendly, and easier to install.

    Just my two cents ...

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    Taz,

    Thanks for the tip about the interchangability of the APP and TAC module on the trucks. I didn't realize that group of trucks interchanged. I have always just tried to keep everything together when doing a swap to avoid any issues.

    I understand the pitfall of having to do not only the cable TB, but also the cable cruise control module. Luckily, most of the swaps I have done are on old vehicles (pre 1980's) so there is reasonable amount of room to mount stuff. I would still like to find a DBC OS just so I have the option of keeping the cable TB. The current swap I am planning will most likely be a DBC just due to the parts that I have to work with.

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    Roger that ...

    One final suggestion .... try and obtain the Flex Fuel sensor from the donor vehicle. The 2002 to 2006 variant is nearly $800 from GM, although these can often be found in the $300 to $400 range from other sources.

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    Did you ever find a 512k OS for an L59?

    If the OS is DBW, can you convert it to DBC? I would like to do the same thing by installing a flex fuel sensor and Flex Fuel OS on a 411 pcm that is DBC, but need to find an FF OS that is 512k and be converted to a COS for 2 or 3bar.
    Last edited by gpr; March 19th, 2015 at 10:34 AM.

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