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Thread: Please HELP! New to 2 Bar OS and Turbo's

  1. #1
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    Question Please HELP! New to 2 Bar OS and Turbo's

    Good evening, I posted a tune earlier regarding issues with a MAP sensor with the 2 bar OS but I believe I have resolved that.
    Now I'm looking for some more help. This is my first 2 bar OS and my first turbo. I have tuned several other Gen III's and Gen IV's for cams, injectors, etc. but this is definitely out of my comfort zone.

    The truck is a 2003 Silverado with a 5.3 running the P59 ECM. It has a stage 2 COMP cam, stock injectors, stock fuel pump, VS Racing 75/78 turbo expected to make about 8lbs of boost.

    I applied the 2 Bar SD OS and calibrated the VE table the best I could figure out. I copied the rows from the stock VE table to correlating rows in the 2 Bar VE table, added 120 across the 210 kpa row and then interpolated between the 100 and 210 kpa rows.

    From there I went to fail the MAF going into the Engine Diagnostics tab, Airflow, and putting MAF Frequency Fail Hig at 0. I then changed the P0101, P0102, and P0103 to MIL on the First Error. Every time I try to fail the MAF to tune the VE table the truck will crank and run for about 30 seconds and then die. I looked at forums on here and found that I could change some settings in the Dynamic Airflow table to 0 and that would also fail the MAF. It stays running with that, but not confident that the MAF is failed.

    First question I have is why does it die when I fell the MAF the way I have always failed the MAF? Am I doing something wrong? Do I need to change something somewhere else in the tune? I have attached the Tune and Log here for that.

    Next is tuning the VE table. I set up the AFR error histogram and start tuning the VE table (again not sure if it is even doing what it is supposed to because not sure if the MAF is failed). Did several runs and changes and then on the final change I made tonight it started getting a lean condition. Have not done any WOT tuning (not there yet). That tune and log is attached as well as the log and tune right before those changes were made.

    Finally, can someone look to see if I have disable the STFT and LTFT appropriately?

    Sorry for all the questions, but I'm stumped now. Worked on this for several hours tonight and had to stop and reach out for help.

    Anything anyone can share will be greatly appreciated. MAF Failed and Dies Log.hplLog before Lean Condition.hplLast Data Log_Lean Condition.hplMAF Failed Tune.hptTune Prior to Lean Condition.hptLean Condition.hpt

  2. #2
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    Quote Originally Posted by kcarruth25 View Post
    MAF Failed and Dies Log.hplLog before Lean Condition.hplLast Data Log_Lean Condition.hplMAF Failed Tune.hptTune Prior to Lean Condition.hptLean Condition.hpt
    Can you help narrow that down please? One tune file, and one log file taken while that file was loaded, that shows the problem you're trying to solve. I don't need to try to figure out which log is from what file etc.

  3. #3
    Tuning Addict 5FDP's Avatar
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    Doesn't look like you copied over that VE right.

    Copy over the matching rows, like 30,40,50 etc etc from the stock VE. Then put like 115 in the last row and interpolate between vertical bounds and then take the whole tabl and click smooth once or twice.

    The way your VE is right now has way less fuel in it because it wasn't copied over right for 30-100kpa. Obviously you can't do much tuning at all because the stock injectors are too small for anything.

    It should fail the MAF if set to 0hz and report a P0103 in the log if it works.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  4. #4
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    Quote Originally Posted by 5FDP View Post
    Doesn't look like you copied over that VE right.

    Copy over the matching rows, like 30,40,50 etc etc from the stock VE. Then put like 115 in the last row and interpolate between vertical bounds and then take the whole tabl and click smooth once or twice.

    The way your VE is right now has way less fuel in it because it wasn't copied over right for 30-100kpa. Obviously you can't do much tuning at all because the stock injectors are too small for anything.

    It should fail the MAF if set to 0hz and report a P0103 in the log if it works.
    Thank you! So any idea why when I do fail the MAF the truck dies after about 30 seconds of running? I go back and turn the MAF back on and it runs fine?

  5. #5
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    Quote Originally Posted by blindsquirrel View Post
    Can you help narrow that down please? One tune file, and one log file taken while that file was loaded, that shows the problem you're trying to solve. I don't need to try to figure out which log is from what file etc.
    Sorry, I know that was a lot, was trying to get all of thoughts out last night. My first question I have is why does it die after about 30 seconds of running after I fail the MAF. That tune and log are attached here. MAF Failed Tune.hptMAF Failed and Dies Log.hpl

  6. #6
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    Quote Originally Posted by kcarruth25 View Post
    Thank you! So any idea why when I do fail the MAF the truck dies after about 30 seconds of running? I go back and turn the MAF back on and it runs fine?
    Also, what size injectors do you think he needs with his set up? 60lb? Any recommendations on the fuel pump size as well?

  7. #7
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    This is a big part of why it won't run:

    screenshot.28-05-2022 09.48.03.png

    Did you manage to find a new MAP sensor that uses the linear/offset of 200/10.33, the defaults filled in when you change to 2bar OS? Or does that still need to be changed to match the actual sensor you're using?

    MAF Fail High should be '0' not '15'.

    If you expect HP to be 650 or less all you need are factory GM L96 injectors (~50lb/hr), and those are dirt cheap. More than that you will need quality aftermarket injectors, and good aftermarket injectors that come with all the right data are expensive. If this is a budget deal that's a valid reason to limit your HP dreams: under-$100 injectors vs. $700 injectors.

  8. #8
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    Thank you! I know the VE table looks crazy but I believe I didn?t calibrate it correctly originally. I did not update the MAP settings (I couldn?t find the ones for the one he purchased). Any recommendations on finding the correct info? Could the map settings be causing it to die when I fail the MAF? The VE table looked way different when I originally tried to fail the MAF. the truck will literally be running and idling fine and then just die. No indication it?s about to die, just dies. I turn the maf back on runs fine.

  9. #9
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    What is the part number for the MAP sensor? It's technically possible to figure the linear/offset of an unknown sensor (find the mV-per-kPa, then extrapolate that out to the theoretical 5.00V and 0.00V points), but you need something more precise than an analog vacuum gauge, and by the time you start buying lab-type equipment it's much cheaper to just buy a sensor with known specs.