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Thread: 2003 Silverado VE Tuning Problems

  1. #1
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    2003 Silverado VE Tuning Problems

    I just acquired a 2003 Silverado that had a 2000 Yukon 5.3 swapped in it. I'm currently trying to tune the VE table but some weird things are happening. I'm not super proficient with tuning yet but I have been reading through the tuning school books to try and get it dialed in. The issue I think I'm having is my wideband is reading different than my LTFT when I log. It seems like its running super rich and I keep trying to lean out the VE table but I feel like all I've done was make a hole in the table and it still runs rich for some reason. I'm not making any progress here and would appreciate the help!

    Specs:
    5.3
    241 heads
    headers
    no cats to 2.5 exhaust
    Summit SUM-8709R1 cam and springs
    Stock intake, tube and air box

    Here is the tune that's on the truck and the latest log I have
    WORKING TUNE (SD).hpt
    2003 Silverado 5.3 VE Log.hpl

  2. #2
    Tuning Addict blindsquirrel's Avatar
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    2000 Yukon injectors or 2003 Silverado injectors?

    When you have a mix-n-match of parts from different trucks of different years, just saying 'stock x, y, z' doesn't clarify much.

  3. #3
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    Injectors are stock to that engine. Everything on the engine minus heads, cam and exhaust is from the 2000 Yukon. Sorry for the confusion.

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    Verified fuel pressure? Verified via numbers on the injectors that they are what they're supposed to be?

    You need to add O2 mV & Injector PWs to your logs, at the very minimum. Look around some and there should be Gen 3 threads with suggested channel lists, somewhere.

  5. #5
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    Your primary and secondary VE tables need to match. You can copy with labels/paste to do this quickly. They seem to use the secondary first then the primary. Why I have no idea.

    I noticed your wideband stopped reading at one point. Its possible that bit of junk data is skewing your tables/histograms.

    Just to be clear. If your fuel trims are pulling out 10% of fuel and the wideband then reads 14.7.. That doesn't' mean the wideband is off. It means after the fuel trims have made their correction the fueling is correct. and a -10% change should be made.
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  6. #6
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    Ok I just made the VE tables the same. Ill do another log here in a little while and report back. Thanks for the help so far

  7. #7
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    So I reset the VE table back to stock and retuned it and made changes to both primary and secondary and this is what I came up with. I don't feel like I'm making an improvement at all.

    2003 Silverado 5.3 VE log 1.hpl
    2003 Silverado 5.3 VE log 2.hpl
    2003 Silverado 5.3 VE log 3.hpl
    2003 Silverado 5.3 VE log 4.hpl
    2003 Silverado 5.3 VE log 5.hpl
    2003 silverado 5.3 VE log 6.hpl
    WORKING TUNE (SD).hpt

  8. #8
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    If you're using LTFT's then you have to clear them with VCM Scanner>Vehicle Controls & Special Functions every time you load up a new revision.

    See what happens with this.

    Are those stock injectors?
    Attached Files Attached Files

  9. #9
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    I did clear them every time and yes they are the stock injectors. I'm loading it to the truck right now and will report back.

    Thanks!

  10. #10
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    Alright. Just in case you didn't know, they don't need cleared for each log.

  11. #11
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    Loaded the tune and took it for a little drive and I would say its better! So what am I doing wrong? Should I take the info from the log I just did and paste special multiply by % half? to both VE tables?

    Could you please explain to me what you did? I'm determined to figure all of this out.

    Thanks!

    2003 Silverado 5.3 VE log 8.hpl

  12. #12
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    This and last I applied LTFT+STFT Multiply-%. Then I eyeball it and interpolate/extrapolate by hand. Smoothed by hand. Next will probably be by %-half if trims are close. All this happens in the Primary table. Once finalized, send it to Secondary.

    Keep an eye on the wideband make sure things are tracking up top. As for your question about wideband vs fuel trims think about it. They're so different because wideband is reading fuel AFTER corrections are made.

    Start logging Cylinder Airmass.
    Attached Files Attached Files
    Last edited by SiriusC1024; 1 Week Ago at 09:03 PM.

  13. #13
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    Ok that makes sense about the WB. I loaded the tune to the truck and will log it tomorrow on my way to work. I noticed you changed a bunch of other tables were those working against me as well?

    The truck has a magnum t56 in it and for some reason when I push the clutch in coming to a stop it will hang the idle for a few seconds and then try to stall. I have tried everything I know to get it to stop doing this.

    Thanks again for the help.

  14. #14
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    The best way to handle it is to address idle problems after VE is done. The spark tables were adjusted for KR. Spark over/underspeed was high, too.

  15. #15
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    Getting way better! AFR gauge was reading fine the entire time. So now you multiply % half?

    2003 Silverado 5.3 VE log 9.hpl

  16. #16
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    Yes. Trims are pretty close now, except for 400-1600rpm. Still, %-half will do. As you're making changes to the VE table think about the trends that are developing. That'll help you with the missing cells.

    I don't like the way it gets into high load without going into PE. Lower TPS threshold to something like 70%. Reference wideband for PE zones.

    Modify spark to address KR. Remember that in SD the Low table is used. That means match the tables after you've made changes. Also, zero out the Fuel Base spark table. Is the EGR intact? There's a spark adder table for it as well, which could be the KR culprit in this case.

    I see where the engine started to die. I believe BRAF is low (Idle>Airflow>Base Running Airflow). Multiply the table values by 1.25 for now. Next log include IAC counts and Idle Adapt (STIT) for tuning that part.

    Most importantly, double check the injector part number. Read it off the actual injector and report back.

    Include your latest tune and log. I want to see how it went.
    Last edited by SiriusC1024; 1 Week Ago at 09:51 AM.

  17. #17
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    Ok I made the changes you suggested. I will log it on the way home from work.

    The EGR is not on the truck anymore so I zeroed out that table.

    My injector part number is 25323974. So I believe its correct in the ECU

    WORKING TUNE SD_4.hpt

  18. #18
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    Most of the places selling that injector # would make me leery of using them.
    Not many references to them on here but here is the most recent.

    https://forum.hptuners.com/showthrea...l=1#post760767
    See post 55 & 56.

  19. #19
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    I don't think I'm having injector issues? Aren't those just the stock GM injectors? I checked fuel pressure and its at 58psi and stays there.

  20. #20
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    Alright man I'm stoked because it seems like the trims are really close. It runs way smoother also. I watched the WB and when I get on it it shoots down to 12. Its still wanting to die when coming to a stop so I need to investigate that some more.

    2003 Silverado 5.3 VE log 10.hpl