Page 3 of 6 FirstFirst 123456 LastLast
Results 41 to 60 of 114

Thread: HOW TO: Setting up Fuel Trim Graph in VCM Scanner V3 on Virtual VE Vehicles

  1. #41
    Tuner JMsquared's Avatar
    Join Date
    May 2014
    Location
    Nashville Tn
    Posts
    89
    Oh oh...all this info might be sinking in...so...It doesn't really matter what is being commanded?? because EQ Ratio Error is simply recording the error between commanded and actual?.

    I almost came to this conclusion about two weeks ago...I was looking at my graph, where it commanded .956Lambda...I had about the same % of error...but I dismissed that as coincidence!

    That means Ive been worrying about these numbers needlessly. Thanks for clarifying.

  2. #42
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    Right--doesn't really matter what it's commanding aside from not wanting to be lean @ WOT or something dumb like that

    It just compares commanded vs. wideband reading and the differences is the error value that it spits out.

    It's a lot easier to see if you just have straight 1.00 and maybe at WOT/PE it goes to 0.8 or something like that but it doesn't have to be that simple, the math works regardless
    Last edited by schpenxel; 07-15-2016 at 01:30 PM.
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  3. #43
    Tuner in Training
    Join Date
    May 2015
    Posts
    17
    big help! Many thanks!

  4. #44
    Tuner in Training
    Join Date
    Aug 2014
    Posts
    15
    So how do you actually edit the Virtual VE table after logging the data?

  5. #45
    Tuner in Training
    Join Date
    Aug 2014
    Posts
    15
    Quote Originally Posted by schpenxel View Post
    Basically just copy the entire "corrected" VVE table, change the drop down box on the left to manifold switch open, paste the VVE table in and hit calculate coefficients again and you're done. Only one of the two is actually used on a lot of vehicles, but it seems that the one that comes up by default is the one that isn't used on a lot of vehicles.
    What does the calculate coefficents button do after you make changes based on your log? Why is this necessary?

  6. #46
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    To update the speed density coefficients....

    Do some reading on virtual VE and I think it will make more sense. Basically instead of having a plain "VE" table, GM switched to using a formula based system on newer ECM's, which uses some pretty massive formulas/coefficients so the computer can use to calculate VE instead of having a table to look it up in. It's easier for it to do it that way (supposedly) but the formulas mean nothing to the average person.

    The virtual VE editor looks at those formulas/coefficients and spits out a graph in the format we're used to so we can then edit it.

    After you make changes to that graph you have to "apply" those changes to the coefficients, which is what that button does. It re-calculates and best fits the coefficients to the new (changed) graph that has been created.

    I think there are some youtube videos on it that explain it in more detail.
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  7. #47
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    Great thread !

    I'm trying to clean up the part throttle tuning. I am very new to hp tuners and just trying to get my head wrapped around this.

    I have a few questions:

    we are looking at long term fuel trims and short term fuel trims combined. Do I need to set a value somewhere else so that its trimming to the value i want?

    If the computer is making these fuel trim changes already why is it better when I make the changes to the vve tables? Seems like it would be the same thing

    I have a flex sensor and currently the fueling feels way better when I'm running e85 then pump gas. How can I tune it for. Both ?

    Thanks so much for your time and effort the number of parameters that are adjustable and what they do is very overwhelming at this point in the learning curve.

  8. #48
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    Quote Originally Posted by ctsvnut View Post

    we are looking at long term fuel trims and short term fuel trims combined. Do I need to set a value somewhere else so that its trimming to the value i want?
    I don't understand the question?


    Quote Originally Posted by ctsvnut View Post

    If the computer is making these fuel trim changes already why is it better when I make the changes to the vve tables? Seems like it would be the same thing
    In the end bottom line injector PW will be the same for closed loop areas either way. It'll take a small period of time for it to adjust if the tables are wrong and can also be off during transients which makes it not drive as smooth. The difference matters more in PE where fuel trims don't work. Positive fuel trims in other areas can carry over to PE making it run richer (probably not going to hurt anything).

    But.. your point is why I don't get hung up on 1, 2, 3% fuel trims. Some try to get them to 0% average--it's just not worth it to me and will never be perfect

    Quote Originally Posted by ctsvnut View Post

    I have a flex sensor and currently the fueling feels way better when I'm running e85 then pump gas. How can I tune it for. Both ?
    My best guess is something is different in transient fueling, or maybe ignition timing is different for the two and making it feel different?

  9. #49
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    Thanks for the response

    What I'm asking is what air/fuel is it trying to achieve with the trims? And is that a value I can set somewhere? Like an auto tuner. Can I say make the air fuel 12.5:1 and the fuel trim tables will say how to get there.


    Quote Originally Posted by schpenxel View Post
    I don't understand the question?



    In the end bottom line injector PW will be the same for closed loop areas either way. It'll take a small period of time for it to adjust if the tables are wrong and can also be off during transients which makes it not drive as smooth. The difference matters more in PE where fuel trims don't work. Positive fuel trims in other areas can carry over to PE making it run richer (probably not going to hurt anything).

    But.. your point is why I don't get hung up on 1, 2, 3% fuel trims. Some try to get them to 0% average--it's just not worth it to me and will never be perfect



    My best guess is something is different in transient fueling, or maybe ignition timing is different for the two and making it feel different?

  10. #50
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    It's always targeting lambda = 1. There's really no way to change it. Narrowband o2 sensors can't do much else

    Some have messed with the switch point voltages with varying results but that's about the only possible option

  11. #51
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    I thought my 2011 ctsv had wide band o2's.

    Quote Originally Posted by schpenxel View Post
    It's always targeting lambda = 1. There's really no way to change it. Narrowband o2 sensors can't do much else

    Some have messed with the switch point voltages with varying results but that's about the only possible option

  12. #52
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    Nope

  13. #53
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    so I have set each axis multiple times to make sure they both match up and im still getting this error when I calculate coeficients

    im highlighting the ltft stft chart and copying

    going to the vve charts and pasting special and using multiply by %
    Attached Images Attached Images

  14. #54
    HP Tuners Owner Keith@HPTuners's Avatar
    Join Date
    Sep 2002
    Location
    Chicago, IL
    Posts
    6,394
    Click Show Zone Numbers and you'll see what zone numbers are missing.
    We got this guy Not Sure, ...

  15. #55
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    Post tune and do what Keith said.

    Have you messed with the RPM/MAP boundaries?

  16. #56
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    the zones listed 17,23 and 29 are missing from the VVE table, they all look like they would at a manifold pressure greater then 105?

  17. #57
    Tuning Addict 5FDP's Avatar
    Join Date
    May 2012
    Location
    Rogers, MN
    Posts
    13,533
    They are above 105kpa.

    Change the map axis on the side to support 2 bar. Just click the Manifold absolute pressure on the side and open the window, click the bottom drop down and click the second set of numbers to make it 2 bar.

    Don't forget to fail the MAF when tuning the VVE, otherwise all your readings are going to be off if the engine is still using the MAF sensor to run. The VVE looks kinda choppy so my guess is that you haven't been failing the MAF.
    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.

  18. #58
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    awesome. thanks, got it , how do I fail the MAF, no I was not doing that

  19. #59
    Moderator
    Join Date
    Mar 2014
    Location
    Raleigh, NC
    Posts
    6,347
    Engine diag, airflow, maf freq fail high to 1hz

    DTC P0101, 102, 103 to MIL on first error

    Start engine, check to make sure at least one of those codes is present

  20. #60
    Tuner in Training
    Join Date
    Jan 2017
    Posts
    24
    you guys rock, thanks so much!!