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Thread: howz this

  1. #1

    howz this

    Hey guys check out this closed loop log and tell me if it looks good to you.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    It was pretty lean warming up based on the fuel trims, then a few minutes later it was rich.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  3. #3
    Yeah I as wondering if this is close to normal or if this is going to work going closed loop. I've this single turbo 4.8 with Cam tuned pretty well in sd and MAF. I thought I would try the cl today. It cranked and ran fine. I just idled in the shop for a few. I noticed the swings, will it work? This is an E38 and I've read you can't adjust the o2s or delay them without using PE.

  4. #4
    Tuning Addict 5FDP's Avatar
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    I would try to smooth it out more. If it's that rich at just idle while it's warm, I'd venture to guess the trims are still going to say it's rich while under load and driving.

    I'd want the trims to be within 5% of zero on a mild cam and maybe a touch more on something bigger. But on larger camshafts I just disabled long term trims altogether and tune the MAF/VE with the wideband and keep the short term trims active in closed loop.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  5. #5
    I think that's the cranking fuel that's making rich at startup. What does enabling only the STFTs do,is it just for monitoring? Do they change fueling any?

  6. #6
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    Short terms are an instant fueling reaction, long terms learn the trend of fueling and curb it slowly the right direction so it doesn't overshoot but both st and lt make adjustments. The only monitoring O2s are the ones behind the cats, they only check the integrity of the catalytic converters and do not change fueling.
    14 GMC sierra 5.3

  7. #7
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    Seems like your MAP sensor readings are very high for idle. Maybe because the cam though? Vacuum leak will mess fuel trims up terribly...
    14 GMC sierra 5.3

  8. #8
    The cam is pretty lopey, it's taken about 4 months to get to this point. Not knowing anything before. So I'm happy with the results so far. The original goal was to go back closed loop. Any wisdom on transients and injector timing? I question the time the larger injectors operate and wb is not steady during Accel/decel.

  9. #9
    Tuner in Training
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    Did you update the injector info in the ECU, you mentioned bigger injectors?
    14 GMC sierra 5.3

  10. #10
    I did FICs got all data with injectors, may need to look at the transient