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Thread: I'm at a loss, maf tuning

  1. #1
    Advanced Tuner KFXGUY's Avatar
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    I'm at a loss, maf tuning

    I want to apologize in advance for bothering you guys once again. Ive, searched beforehand but no luck. heres the deatails and I really appreciate the help in advance.

    1999 Silverado 5.3
    212/218 texas speed cam
    headers
    trailblazer SS intake swap, 90mm tb

    the problem is I tuned it like all of the guides say to, cut the MAF off, reset trims, log, adjust the ve etc. Its very close now in the secondary table and running on just the map sensor it runs good, drives good and has plenty of power. Gets crappy gas mileage, 8-10. This same setup have knocked down 18-20 with the maf enabled. I copied my secondary table over to my primary and smoothed it and them cut the MAF back on, my LT trims go to 24.2 after a couple minutes. I can change the ve table drastically and it does nothing. Also when I first stat the engine (warmed up every time) it goes lean to 22.2 to 1 afr and stays like that for a minutes and then the ltft start to kick in and it heads down to 14.8 - 15.2 afr. its runs very good with the MAF on but I cant get the 24.2 trims to change for nothing. here a couple tune files. one is the beginning file and the other it one I added a bunch of fuel to part of the ve and I experienced no change. My afr never changes according to my wideband (what I mean is I get the same fueling no matter what ve changes I make to the primary)

    maf tune attempt.hpt

    maf tune attempt2.hpt

  2. #2
    Advanced Tuner KFXGUY's Avatar
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    I know my tune is the crappiest one you'd ever see but I'm still new at this lol. One other thing it does with the maf on is it cranks up fine, idles good for a few seconds then stumbles badly and then smooths out.
    Last edited by KFXGUY; 12-05-2016 at 07:35 PM.

  3. #3
    Senior Tuner mowton's Avatar
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    You haven't failed the MAF properly to tune in Speed density (no MAF). Uou need to set the MAF High Frequency (ECM 4000) to 1 so when the PCM sees a frequency it will fail the MAF on the first error like your DTC p0101-103 ask for.

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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  4. #4
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    Quote Originally Posted by mowton View Post
    You haven't failed the MAF properly to tune in Speed density (no MAF). Uou need to set the MAF High Frequency (ECM 4000) to 1 so when the PCM sees a frequency it will fail the MAF on the first error like your DTC p0101-103 ask for.

    Ed M
    I think he said he is through tuning the VE and has re enabled the MAF.

    OP if the trims are that high through the entire RPM range try highlighting the entire MAF table and multiply it X 1.2 for starters.

  5. #5
    Senior Tuner mowton's Avatar
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    Quote Originally Posted by 2xLS1 View Post
    I think he said he is through tuning the VE and has re enabled the MAF.

    OP if the trims are that high through the entire RPM range try highlighting the entire MAF table and multiply it X 1.2 for starters.
    P0101 -103 is set to fail first error......? And the only difference between the 2 files is the Primary and Secondary VE...looks like he is tuning the VE to me....

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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  6. #6
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    Quote Originally Posted by KFXGUY View Post
    I want to apologize in advance for bothering you guys once again. Ive, searched beforehand but no luck. heres the deatails and I really appreciate the help in advance.

    1999 Silverado 5.3
    212/218 texas speed cam
    headers
    trailblazer SS intake swap, 90mm tb

    the problem is I tuned it like all of the guides say to, cut the MAF off, reset trims, log, adjust the ve etc. Its very close now in the secondary table and running on just the map sensor it runs good, drives good and has plenty of power. Gets crappy gas mileage, 8-10. This same setup have knocked down 18-20 with the maf enabled. I copied my secondary table over to my primary and smoothed it and them cut the MAF back on, my LT trims go to 24.2 after a couple minutes. I can change the ve table drastically and it does nothing. Also when I first stat the engine (warmed up every time) it goes lean to 22.2 to 1 afr and stays like that for a minutes and then the ltft start to kick in and it heads down to 14.8 - 15.2 afr. its runs very good with the MAF on but I cant get the 24.2 trims to change for nothing. here a couple tune files. one is the beginning file and the other it one I added a bunch of fuel to part of the ve and I experienced no change. My afr never changes according to my wideband (what I mean is I get the same fueling no matter what ve changes I make to the primary)

    maf tune attempt.hpt

    maf tune attempt2.hpt
    Whatever

  7. #7
    Senior Tuner mowton's Avatar
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    Quote Originally Posted by 2xLS1 View Post
    Whatever
    What does that mean? Wouldn't you agree it looks like he is tuning the VE. If you would have bolded the next sentence he says "can change the ve table drastically and it does nothing" I believe he is just using the wrong terms and is confusing all of us.

    OP, please clarify what you are trying to do....

    Thank you,

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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  8. #8
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    Well the thread title is asking about MAF tuning isn't it. And I'm not using a version that will allow me to look at his files. I'm going by what he is asking about.

  9. #9
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    I'd take a step back and check the basics before
    you try to "tune" anything. Such as fuel pressure.
    Just because you can get a "right answer" according
    to a sensor, doesn't mean you got it the right way.
    Two wrongs, like, and then you want to hook a
    "right" back up?

    Fuel trims are about more than AFR. Sensors pick
    up exhaust oxygen, which you can get from cam
    overlap, from misfires (lean or rich), from AIR pump
    being on. And sensor crustiness can make low airflow
    tuning suspect too, especially for you folks who have
    an actual winter season.

    Measure twice, cut once.

  10. #10
    Advanced Tuner KFXGUY's Avatar
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    Ed: I was done doing my be and set it back to mag mode. I set the maf to fail, check engine light came in. I disabled the light. Reset trims. Logged. Adjusted accordingly to my secondary table. Ones my trims is sd mode we within +2 or -2 max I moved to the primary table. Copied and pasted the 20 line to the 20. 30 to the 30 etc. smoothed it a couple times. Turned maf back on and now my trims are wack just like they were stock when I did all these mods.

    2xLs1, thanks....yes you understand that I went through my tuning already

    Fuel pressure is rock solid at whatever I set it too. I had a remote mounted gauge and even checked full throttle. It's set at 55 psi.

    We've been in short pants up until a couple days ago. This ordeal has been going on for a while. I've just left it in ss mode but the truck drives much better and gets better fuel mileage with the maf working. It's not my daily driver but I've found myself driving it much more often since I did all the mods. I know my time probably looks all jacked up but I'm trying!

    Any help would be appreciated!

  11. #11
    Advanced Tuner KFXGUY's Avatar
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    I made changes to the second file just to see if there would be a fueling change. Maybe I just need to start all over (ugh!) lol

  12. #12
    Advanced Tuner KFXGUY's Avatar
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    Quote Originally Posted by mowton View Post
    What does that mean? Wouldn't you agree it looks like he is tuning the VE. If you would have bolded the next sentence he says "can change the ve table drastically and it does nothing" I believe he is just using the wrong terms and is confusing all of us.

    OP, please clarify what you are trying to do....

    Thank you,

    Ed M

    Sorry. I went through the normal motions of tuning (according to the guides I've found) and it is tuned fine in sd mode (map sensor only) but even tho I've changed the primary be to match the secondary, my trims tuned them selves back to what they were stock. I'll go through the process again. Maybe I'm missing something.

    Question I've never seen asked: if my computer has learned (100 Mile drive or 1 Hour) does it lose what it learns when I do a reflash? In other words if I make a change does it need to relearn over again?

    Also, since I have a 99 ecm, is it worth it to upgrade to a later model? What year should I look for and is it a direct plug in?

  13. #13
    Senior Tuner mowton's Avatar
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    can you post some logs, it just doesn't sound like you are doing something right.....

    If you are logging LT+ST error than it shouldn't matter about learning. I hope you aren't logging you WB error in closed loop.....that just doesn't work. Show us a log so we can see whats going on.

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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    I'm new to tuning too but learning so I don't think I will have any answers, but was reading in case there was anything for me to learn.

    If I understand you correctly. You have tuned your VE tables and are confident they are good? (using a wideband or fuel trims). Now once you re-enable your MAF your trims are showing fueling errors, which I would expect since you haven't mentioned tuning any MAF values (unless I've overlooked that). Your MAF tables will definitely need work since you have different intake, TB and I'm sure airbox CIA etc.

    So are you asking how to go about tuning your MAF tables?

    Sorry If I'm way off base.

  15. #15
    Advanced Tuner KFXGUY's Avatar
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    Quote Originally Posted by 0069GTP View Post
    I'm new to tuning too but learning so I don't think I will have any answers, but was reading in case there was anything for me to learn.

    If I understand you correctly. You have tuned your VE tables and are confident they are good? (using a wideband or fuel trims). Now once you re-enable your MAF your trims are showing fueling errors, which I would expect since you haven't mentioned tuning any MAF values (unless I've overlooked that). Your MAF tables will definitely need work since you have different intake, TB and I'm sure airbox CIA etc.

    So are you asking how to go about tuning your MAF tables?

    Sorry If I'm way off base.
    Ok so you might be on to something. I wasn't aware that there is a maf table. Yes it's stock parameters in that I'm sure. Where is the maf table and what process do I use to change it? To be clear, all I've been changing is my primary and secondary ve tables. The primary makes no difference at all so I've mainly concentrated on the secondary and the copied the corresponding lines over to the primary when I was done and then smoothed it.

  16. #16
    Advanced Tuner KFXGUY's Avatar
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    Quote Originally Posted by mowton View Post
    can you post some logs, it just doesn't sound like you are doing something right.....

    If you are logging LT+ST error than it shouldn't matter about learning. I hope you aren't logging you WB error in closed loop.....that just doesn't work. Show us a log so we can see whats going on.

    Ed M
    I'll log two logs for you possibly this evening. One in sd mode and the other with my maf enabled so you can see the difference. Thx

  17. #17
    Advanced Tuner KFXGUY's Avatar
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    On a side note, I have a connection with a salvage yard and I can get a 2002 silverado ecm for $40, is it worth the money and time to upgrade from the 99 before I even go through all the tuning steps again? It will cost me $140 total after I buy another credit to tune the newer edition. I see a lot of people have done this, what is the big advantage?

  18. #18
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    I'll let some of the more experienced users chime in on procedures for adjusting. Like I said I'm new and sill learning, so I don't want to give any incorrect information.

    But you should see something like airflow vs. frequency in airflow.

  19. #19
    Senior Tuner mowton's Avatar
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    OK so that is a surprise especially as the tune files in the beginning say MAF tuning attempt.....Never dawned on me you hadn't tuned the MAF...thought you were changing the VE with no effect (which now makes sense :-))

    Tuning the MAF is easier...first go back to the P0101-103 DTC's and put them back to fail on 2nd error.

    Go to Airflow>Dynamic and set High RPM disable to 400 rpm and re-enable to 390 (force MAF only by setting Blended mode to occur when rpm is 400 or less). Make sure you are Logging the MAF AF and MAF Hz channels. Set up the chart to show these if not already there. Set up a Graph that uses the Maf Hz axis and what ever error parameter you are using. The its just like the VE copy and paste the error data into the editor MAF table and repeat until done.

    Ed M
    Last edited by mowton; 12-06-2016 at 04:48 PM.
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

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  20. #20
    Senior Tuner mowton's Avatar
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    Quote Originally Posted by KFXGUY View Post
    On a side note, I have a connection with a salvage yard and I can get a 2002 silverado ecm for $40, is it worth the money and time to upgrade from the 99 before I even go through all the tuning steps again? It will cost me $140 total after I buy another credit to tune the newer edition. I see a lot of people have done this, what is the big advantage?
    No,,,save it as a spare or sell on ebay for $60 :-)

    Ed M
    2004 Vette Coupe, LS2, MN6, Vararam, ARH/CATs, Ti's, 4:10, Trickflow 215, 30# SVO, Vette Doctors Cam, Fast 90/90, DD McLeod, DTE Brace, Hurst shifter, Bilsteins etc. 480/430

    ERM Performance Tuning -- Interactive Learning ..from tuning software training to custom tunes
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