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Thread: DTC settings

  1. #1

    DTC settings

    Did a search, no answer found. Maybe I don't speak the search language good enough...lol.

    A lot of tune vids I have watched for SD tuning say to set the MAF to MIL on first error, and set CEL to off(unchecked). Is this for failure verification only so you can read codes and make sure it is failed? If set to no error reported I assume the codes would not set at all.
    03 Z06 stock.......for now
    05 Siearra 5.3 daily
    I have realized that tuning is a rabbit hole. No problem diving down this hole, in fact I jumped willingly. Just want to avoid hitting every ugly rock or root on the way down it.

  2. #2
    Tuning Addict 5FDP's Avatar
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    Code P0103 should be present when DTC's are pulled/viewed, this way the computer reverts to speed density because it see's that the MAF has an issue. It's easiest to say set all 3 code to first error.

    Setting them to no error reported would not let it know that the MAF has failed and could stop it from going into speed density straight away.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    ok, so it is a failure verification through DTCs set as well as a "kicker" to tell the PCM that MAF is failed. Basically prevents a bottleneck of sorts. What does setting it to "no mil light do"?
    03 Z06 stock.......for now
    05 Siearra 5.3 daily
    I have realized that tuning is a rabbit hole. No problem diving down this hole, in fact I jumped willingly. Just want to avoid hitting every ugly rock or root on the way down it.

  4. #4
    Senior Tuner 10_SS's Avatar
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    I was having a startup then stall due to the MAF Test Fail and Delay timers when the MAF was physically unplugged or my MAF tables are 0'd out, so make sure you turn those two timers to 0. Nobody mentions that.

    It would read no airflow, but the test and the fail delay are both 1 sec, so it would stall about 1-2sec after starting since it would not fail right away.

    I like to make sure it's failed, verify by taking it out of the air stream or unplug, or setting the frequency table to all 0. I you do this the 1 sec timers will get you.
    2010 Camaro LS3 (E38 ECU)
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  5. #5
    My Z doesn't have timers from what I see. My truck is gen 3 as well, same thing. Must be a gen 4 and up thing. Have a gen 5 file that has me set fail freq high and low, and a test delay timer. Can you point me to where the maf test fail timer is?

    Thanks for the tips!
    03 Z06 stock.......for now
    05 Siearra 5.3 daily
    I have realized that tuning is a rabbit hole. No problem diving down this hole, in fact I jumped willingly. Just want to avoid hitting every ugly rock or root on the way down it.

  6. #6
    Tuning Addict 5FDP's Avatar
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    GEN 3's don't have that, like you've seen it's more for GEN 4+ stuff with the timers.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  7. #7
    Senior Tuner 10_SS's Avatar
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    Quote Originally Posted by vettemakesemwet View Post
    My Z doesn't have timers from what I see. My truck is gen 3 as well, same thing. Must be a gen 4 and up thing. Have a gen 5 file that has me set fail freq high and low, and a test delay timer. Can you point me to where the maf test fail timer is?

    Thanks for the tips!
    That's the one. I think my example was completely backwards, lol.

    I think I mentioned earlier it would stall after 2 sec, in reality it was opposite.. would not run until the timers expired, which is about 2 seconds since it's still using MAF for that 2 sec until timers expire.

    Meaning, if I unplugged, removed from airstream, or 0'd MAF HZ to verify it was actually failed in HPT, then tried to start it using the correct settings (stock 1sec timers) it would start on crank pulse fuel then stall, sometimes 2sec would expire at about 100rpm on the way to 0rpm and stumble back to life unless I was able to keep it running or cranking for the 1 or 2sec then it would finally fail and startup normally on VE table so I started messing around with the VE table in those cells, startup airflow, etc, really going down the wrong path.

    I had this happen every time I failed my MAF to tune my VE table.. which I would randomly do over a period of a year. the difference is I would either unplug the MAF or set 0's in the MAF HZ table to verify it was failed, and this would cause the timer problem. One day I was gazing over the tune in complete annoyance and saw those two timers... set them to 0, and BAM, fired right up, perfectly. I really don't think they were there all those years, I tell myself. lol

    Also it would only do it when MAF wasnt failed, so usually the first time after flashing the ECU and starting, which was often. Sometimes shutting off the engine and restarting would start fine since MAF was already failed.

    Engine Diag/Airflow/MAF

    MAFFAIL.PNG
    Last edited by 10_SS; 02-19-2020 at 02:27 PM.
    2010 Camaro LS3 (E38 ECU)
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  8. #8
    And that happened on your camaro while tuning? Double checked my files and found it in a gen5 truck I read awhile back. Thanks for the heads up on that.
    03 Z06 stock.......for now
    05 Siearra 5.3 daily
    I have realized that tuning is a rabbit hole. No problem diving down this hole, in fact I jumped willingly. Just want to avoid hitting every ugly rock or root on the way down it.