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Thread: 04 Tahoe 4wd 3.73 4L80e, .575/.575 .220/.224 .112 cam

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    04 Tahoe 4wd 3.73 4L80e, .575/.575 .220/.224 .112 cam

    Looking for advice on my initial tune and wanting to get correct data for speedo.
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  2. #2
    Tuning Addict 5FDP's Avatar
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    Put your tire size and gear ratio into the gear tire wizard under the edit tab, that should fix the speedo issue so long as your did the segment swap correctly for the 4L80e swap.


    Why is your timing kinda screwed up? This isn't a small block chevy with a distributor.

    The factory timing curves is far better than what you have made. This thing will be a slug if you put any throttle into it. Anything above .40 cylinder airmass and 2,000rpm would be running negative timing to maybe 10-12 degrees until you really rev it out.

    Honestly go back to the stock high/low timing tables and adjust it as needed from there. You are losing power down low because of how low the timing is starting. Creeping up on the timing is fine but the curve you have is not very good. Fuel mileage will also be down because it's running about 15-20 degrees less timing at cruising speed too compared to what some factory tables have and what you are allowed to get away with.

    The MAP sensor is not working in that log. Hopefully it's just a log issue and not a sensor issue.

    You're missing way too much data to safely be flogging it that high in the rev range. I don't see a wideband o2 sensor in the logs. You are running stock injectors and aren't logging the injector pulse width avg. There is no way in hell those injectors can flow enough fuel with how rich of an air fuel ratio you are commanding. I can guarantee you that this engine is well over 100% duty cycle and basically holding the injector wide open when you floor it. Leaning it out to low 12's will net more power than 11.0-11.5 on a NA engine.

    Add cylinder airmass, o2 sensors, throttle position.
    Last edited by 5FDP; 08-16-2019 at 11:59 PM.
    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.

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    5FDP thanks for the tips. This is a first stab at the tune. I will clean up the timing tables on the bottom end. I'll add parameters to log as well. I don't have a wideband o2 therefore I'm limited in that aspect. I'm going to work on it some this morning and log again. I'll report back.

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    5FDP thanks for the tips. This is a first stab at the tune. I will clean up the timing tables on the bottom end. I'll add parameters to log as well. I don't have a wideband o2 therefore I'm limited in that aspect. I'm going to work on it some this morning and log again. I'll report back.
    Also on another note with toe size I used the calculator but I don't think it's correct still.. may be other issues there. There's no way I was going 74mph shifting to 2nd lol

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    So I went back and looked at my timing table. Nor sure how it got that far out of wack.. guess I accidentally hit interpolate on entire graph. I'll have an update shortly

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    Tuning Addict 5FDP's Avatar
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    Getting a wideband should be up there on your prioity list, it's not really possible to know if your fueling is okay without it.

    And with being on the stock injectors, it's pushing your luck up in the rev range under load. There just aren't big enough to safely supply enough fuel. You'll notice that once you get some of the injector information in your logs. Even with leaning it out to the low to mid 12.0 AFR wise it'll still be pushing past 100% duty cycle.
    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.

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    update

    Quote Originally Posted by 5FDP View Post
    Getting a wideband should be up there on your prioity list, it's not really possible to know if your fueling is okay without it.

    And with being on the stock injectors, it's pushing your luck up in the rev range under load. There just aren't big enough to safely supply enough fuel. You'll notice that once you get some of the injector information in your logs. Even with leaning it out to the low to mid 12.0 AFR wise it'll still be pushing past 100% duty cycle.
    I do plan to order wideband. I wish i would've got the pro version when i bought it 10 years ago. I've had it a while and just used it to turn stuff off for swaps but just now getting in to tuning. I read somewhere where I think it was you that added a wideband to the egr input?
    MAP was unplugged and i didn't realize it. guess putting engine cover on pushed tab and unseated it.
    Made a few changes here see what u think. I am having an issue with the truck wanting to die at low rpm when i let off throttle. at high rpm it's a non-issue.04 Tahoe stg2 sloppy 4l80e 4wd 3.hpt04 Tahoe stg2 sloppy 4l80e 4wd 3.hpl

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    Yeah, you can wire the wideband into the EGR. It's not very hard and there are plenty of write up and video's on youtube about it.

    The fueling is still tough to say on. The o2 sensors show it may be lean still but those don't tell the whole story. Possible that is where the knock is coming from because it may be asking for 12.8 but could be up into the 13's. Then depending on how lean you are willing go to or rich would determine injector head room. If it's lean now and you had to fatten it up, it'll raise the duty cycle up. Generally truck engines like the low to mid 12's for good power/torque and it'll give you peace of mind that you aren't running it on the edge just to gain minimal power.

    Getting all the fueling down will make airflow changes and idle corrections much easier. You idle area's for timing should be close to matching in all your tables. The high/low octane tables should be by a copy of each other, the low octane table needs less timing.

    Also with the camshaft you will run the cut the under/over speed spark correction tables about in half to stop the spark for moving so much on you.


    I can't edit your file for you because I only have a MPVI 1 device but I altered a tune just to show you few things. Use the compare feature with my file. It's from a 2006 truck so basically exactly like yours.

    Take a look at the timing curves and power enrichment settings. Give those a try.
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    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.

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    So i went in and made changes based on what you sent me. Now i have a hard start and still dies when i tap gas pedal when in gear. seems as if it may be an accesory load issue...
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  10. #10
    Tuning Addict 5FDP's Avatar
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    It's still not really tuned, so I don't really know what to tell you.

    With the MAF and VE not calibrated and the idle airflow not adjusted, the more you drive the more of these issues you are going to notice. It may need more base running airflow or something like that. There is an idle tuning guide somewhere around here but that should be done once most the fueling corrections are completed.


    Also if you've removed the rear o2 sensors you still have to set the codes to "no error reported". And the P59 computers have a cat test that we can not disabled, so it's best to plug the sensors back in but just zip tie them to the frame. The open circuits cause the test. I can be seen in logs when the commanded AFR goes to 15 and then down to 13 before returning to stoich.
    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.