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Thread: 12672612 OS in a swap no fire issue

  1. #1
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    Default 12672612 OS in a swap no fire issue

    I'm about to pull my hair out, cannot get this file to run the L83 on the engine stand. Here's some facts:

    Our run stand engine is fine, its a 2016, 4 wire pressure sensor (non-SENT type sensor)
    It has run multiple other harnesses and ecms
    We have tried a resistors and even actual relays on x1 #63 and 72 like normal. We've tried different combinations on both these pins.
    Vats removal has been done as far as the options I have in front of me (red folder in the "Operating system patches" but no VATS on the System folder. Only crank options in the system folder)

    The engine has no signs of life, no sputter, no stumble, nothing. It does NOT have fire at the plugs. I assume at this point the ECM is not telling them to fire. I do have cam counts and RPM counts on the scanner. All the other sensors appear to be transmitting logical data, MAP, MAF, ect. There are no CELs other than the AC pressure transducer, which has never stopped one from running in the past.

    This my first time touching this particular operating system. Ironically the only other E92 in my hands right now is the same OS. Haven't unlocked it yet, that option is on the table but if it is an oddball OS issue it will likely be there as well.

    I searched this OS here on the forum and only found one thread with it. A guy was having issues with an 8L trans paired with it, but as far as I know it was in the original vehicle, not a swap. I just want to get another set of eyes on this. Have I missed something obvious on the tune? Is there something special about the 12672612 that I am not aware of? The majority of other E92s that we have run were either 2014 or 2017s, not sure why those 2 years but that's what most have been by chance. Just hoping for some moral support here while we continue to check connections and whatnot. Been at it for about 6 straight hours now. Thanks

    2016 5.3L New Revision.ctz

  2. #2
    Lifetime Member GMPX's Avatar
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    After 6hrs you are probably over it, LOL.
    I'll have a look for you at the parts we can control, but essentially it should be no different to any other E92. VATS disable patch simply tells the ECM no matter what the state of the VATS is (of course it will fail on an engine stand) still allow the engine to run.
    Then the final one on these is they check the starter relay output, if it is open circuit then it won't allow the engine to fire.
    Given you've put a relay on that output just to make sure it probably isn't that.
    I no longer monitor the forum, please either post your question or create a support ticket.

  3. #3
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    Thanks, yes we've tried using a resistor like we normally do on the other E92s over the last year or so. No luck. We even put an actual relay in the mix, just like it would be in the original Silverado just to be sure. No change. I've compared to the known good files that I have. Just side by side on a split screen. Files that without a doubt ran in front of me on this same stand. The 2014s seem to have an actual "Vats type" option, 1,2,3,4 in addition to the clutch pushed in option. On the other hand the 2017 and 18s I looked at don't have the cranking folder at all, just the red vats patch. These 2 2016s in front of me (the unlocked ecm with the same OS) are in between. They have the red folder vats patch of course, and a cranking folder, but no vats type option. Oh how I love the intricacies of all the different operating systems

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    I'm still at a loss. Going to go buy a 2014-15 ecm from the salvage yard and unlock it, just to see if I can make something change!

  5. #5
    Lifetime Member GMPX's Avatar
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    Quote Originally Posted by LS-SWAPPER View Post
    Thanks, yes we've tried using a resistor like we normally do on the other E92s over the last year or so. No luck. We even put an actual relay in the mix, just like it would be in the original Silverado just to be sure. No change. I've compared to the known good files that I have. Just side by side on a split screen. Files that without a doubt ran in front of me on this same stand. The 2014s seem to have an actual "Vats type" option, 1,2,3,4 in addition to the clutch pushed in option. On the other hand the 2017 and 18s I looked at don't have the cranking folder at all, just the red vats patch. These 2 2016s in front of me (the unlocked ecm with the same OS) are in between. They have the red folder vats patch of course, and a cranking folder, but no vats type option. Oh how I love the intricacies of all the different operating systems
    The VATS type is actually pointless in this ECM, it was relevant in E38's etc, but in these it doesn't matter what type is defined the code ends up at the same place to enable or disable spark/fuel.....where our patch is applied.
    Does a 2014 run the engine? Just trying to discount an issue that might not be the ECM at all.
    I no longer monitor the forum, please either post your question or create a support ticket.

  6. #6
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    That's where I'm at right now. I have 3 e92 ecms in the shop right now.

    This one

    Another 2016 that is same OS, unlocked at the moment

    And an unlocked 2017.

    I have the capability to jump wires and change out to the SENT rail pressure sensor, but I'd have to knock out a cavity on the ECM connector, don't want to do that but might.

    I'd rather just grab a different 2014 ECM and unlock it. I'd keep it around the shop for testing.

  7. #7
    Lifetime Member GMPX's Avatar
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    Well at least they are cheap to keep a few around for testing.
    I no longer monitor the forum, please either post your question or create a support ticket.

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    Ok, I'm still at this. I have fully lost my mind at this point. I got a 2015 E92 with OS 12664769 that we flashed and turned vats off etc. Still no fire. So I assume we have something wrong somewhere else, harness, etc.

    Please bear with me, I would like to back all the way up and make sure I am not doing something wrong. Again, we have done a half dozen or so harnesses/flashes and test fires of e92s on this run stand so it isn't our first rodeo, but perhaps we have simply overlooked something obvious.

    With key on have power feed into

    X1 51, 73, 67, 62 and 70

    Battery 12v+ is going to X1 52

    No different than any others we have done

    On to the resistors...the only ones in question that I am aware of is:

    X1 72 that grounds out the ignition control relay. We currently have a relay connected. When the ignition is turned on the relay clicks to life, so the ecm is grounding x1 72. All seems to be good.

    x1 63, the starter relay engage. This one I'm a little unsure about. Seems like some OS need it, some don't. We have tried a 100ohm resistor to ground, we have also tried actually putting a relay in place to simulate the original wiring. The GM diagrams for 2015-2016 show the ecm supplying 12v positive trigger to the relay. I don't see any evidence that it is doing it. No relay click, no voltage when checked with a multimeter. I remember putting this terminal resisted to ground on a 2017 and it all worked. I didn't research exactly what all was going on in the background. Is there more to this? Do the 2 operating systems I am dealing with today need it (12672612, 12664769)? I feel like this is my area of least understanding, perhaps the problem is here.

    However, I should add that we sporadically get a P0686 code! "Control Module Power Relay Control Circuit Low Voltage". To me this is a BIG red flag. To me this code deals with X1 72 triggering the relay and in turn providing power to X1 51, 73, 67, and 62. HOWEVER, is it saying there is low voltage detected on pin x1 72? Or is it saying voltage is low to the X1 51, 73, 67, 62 pins? We have backprobed the terminals and I seem to always have 12+ volts on X1 51, 73, 67, and 62. It seems though, that herein lies the issue. Something with voltage or relay on those pins. I'm sorry if this is long winded, my brain is fairly fried at this point. I could really use some clarity. thanks.

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    Maybe I am missing something...I now have a DIFFERENT 2016, same OS, #12672612 and it will not fire up on the stand. My 2014 e92 test ecm runs everything fine. So either there is something going on in some of these 2015-2016 OS that we are not aware of or I am just personally doing something wrong with the flash.

    Has ANYONE succcesfully had a 12672612 tune run stand alone??? We are not utilizing the main relay trigger from the ECM (X1 59) but we don't use that on any of them. The 2014s and the 2017s don't seem to care about it.

    Here is the stock tune with just the basics turned off to so it would fire up on the stand. Please, someone help me look into this.

    2016 Silverado E92 5.3 for 6 speed auto Modified.ctz

  10. #10
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    Ok I know alot about these new gen GM first thing is this a motor swap or it's in a actual 2016 GM truck? Another thing from my experience I have not been able to remove the vats on a 2015 and up GM with efi live I have installed the patch changed the os on it and everything and nothing it flashes correctly and everything but no crank nothing. Then I purchased HP tuners and removed the vats and disable the starter crap then I full flashed it and the truck started like a champ.
    Last edited by sikkls2; November 3rd, 2019 at 04:47 PM.

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