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Thread: turbo 5.3 cutting out under load/boost ???

  1. #1
    Tuner in Training
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    Oct 2019
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    turbo 5.3 cutting out under load/boost ???

    5.3, elgin e-1840-p cam,pac racing valve springs, stock return style rails/regulator, gt45 turbo, no I/c, installing watermeth soon- in a full weight short bed 86 c10.
    th350 trans.
    truck will start to get into boost , wideband reads good (12.5ish AFR under heavy throttle) and it will just drop off...like I abruptly let off the gas pedal...but runs as it should after that episode...beginner tuner here....ill attach tune and log with this aswell
    Attached Files Attached Files

  2. #2
    Tuning Addict 5FDP's Avatar
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    More information is needed.

    What fuel injectors are you running?

    Why is stoich set to 15.4? Stoich must match the fuel in the tank, regular gas is 14.68, E10 will be 14.2. Do not change stoich to make the fueling correct. It's a set and forget table, the airflow model must be calibrated to achieve stoich or whatever the commanded AFR is using a wideband.

    In the power enrichment tab you setup the boost enrichment table incorrectly. The number plugged in is 11.50, which would be incorrect based on how the table functions. It functions the same way as the regular EQ ratio.

    The PE is setup as 1.180, which would give you 12.44 AFR based on a 14.68 stoich ratio. The BE eq ratio is 11.50, so with a stoich ratio of 14.68 that is 1.27afr when doing the math. You can see the problem here.

    It should be setup as 1.275 when using 14.68 (stoich) to give you a 11.50 commanded AFR. So fix that table.

    COT needs to be disabled.

    Do not zero out the maximum knock retard table if you are still using knock sensors. There needs to be a value in there so it can pull timing in case of knock. Put it back to the stock 6 or 8 degrees.

    Because this computer was not a manual from the start, don't change the transmission type. Leave it as it was stock and disabled all transmission related trouble codes and abuse mode. Weird background problems can happen when you change that stuff at random.


    The data logs are missing tons of important data. Like injector pulse width avg for both banks, knock retard, burst knock, cylinder airmass, commanded AFR or EQ ratio, there is not wideband data either.
    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.

  3. #3
    Tuner in Training
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    sorry I thought I input my injector info...(drrrrp).decapped truck injectors professionaly cleaned and flowed, & what exactly is COT ? sorry again...some of tuning abbrevations I have not picked up on yet. and unfortunetly I don't have the output to plug into my new hp tuners Bluetooth device to attach the wideband. ill fix these things, add those things on the scanner and return

  4. #4
    Tuning Addict 5FDP's Avatar
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    Cat over temp. It's still enabled.
    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.

  5. #5
    Potential Tuner
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    Sep 2019
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    try logging the voltage from the tps throttle position sensor. see if it is smooth or jumpy if jumpy could be bad spot in reostat. do it with engine off.
    also check fuel pressure with a gauge on the fuel rail with RPMs up over 4000 for a half second if it is not steady like at idle could be fuel.

  6. #6
    Tuner in Training
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    Oct 2017
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    Morning c10turbolsx,
    Any chance you sorted out your tuning issues? Mind posting your tune for ref?