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Thread: Need some help with understanding the DFCO.

  1. #1
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    Need some help with understanding the DFCO.

    Working on tuning the VE tables and one of the issues I have is that low map, 20-40 areas, upon deceleration, seems to be on the rich side.

    I read a little about how the potential issue could be wet walls from the intake.

    Would a spacer between the TBI and intake take care of this?

    In any case, I might have more adjustments to make across the table itself, albeit, it looks like I am probably close enough with the exception of the high vacuum/no load areas.

    It seems that after making adjustments, the BLM's get worse on the rich side.

    A good example is seen in the following log starting at time 19:40.

    ALSO, I am still curious about the spread sheet used for adjustments, specifically:

    1. Of the logs I have done, I have noticed at most, a 3 point difference between the history and the running averages. Why is the History average better to use?

    2. On the spreadsheet, specifically, what is the difference between the "new BLM with averaged tables" and "without"? Which is better to use?

    I ask this because if one is better than the other, then why have the options there? For people like me that like to over analyze things, it ends up being more of a distraction. (well, maybe just me....)

    here is the bin and log:
    Attached Files Attached Files

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    are you realy neededing devco? or are you just playing, you can adjust it by map sensor rpm speed,and blms under what ever your map is set at [kpa] to disable devco is what I do on my truck. it will change the 30 [kpa ] reading when you change the 20s.i don't remember if you have a auto or std trans. better mpgs costing. I use running average, also running sample count if the running sample count is below 5 don't change that cell unless it is suspicious looking. iam using tp to change a few things an data log when I go to adjust ve1 I open my data log on tp then use tuner cat to adjust the table. I will look at your log an bin if tuner cat will open your bin I will see if I can help you.
    Last edited by ony; 12-04-2013 at 04:40 AM.

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    your map is not going low enough for devco. try this bin I changed the v1 table where the cells was filled long enough. I don't know what you are running but very few knocks for that much timming, have you got a distributor or a moudule distributor less engine?
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    Ony,

    Running a 3.4 with the 2.8 distributor and 7747 ecm.

    Using that bin due to the better performance so far because of what I believe to be the Spark Latency tables and what not matching up better with the 2.8's.

    Will try that bin and see what happens.

    Thanks!!

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    Quote Originally Posted by damanx View Post
    In any case, I might have more adjustments to make across the table itself, albeit, it looks like I am probably close enough with the exception of the high vacuum/no load areas.

    It seems that after making adjustments, the BLM's get worse on the rich side.
    Your DFCO is not disabled so can't adjust VE. If it is truely is DFCO? Or is it Decel Enlean? Which can also be zerod out... or my guess is your spark advance table is still not truely die=aled in for your 3.4L engine intake combination and it could possibly be a misfire throwing off the O2 sensor and your BLM readings? This is where a Wide Band is a better tuning tool as well.

    Quote Originally Posted by damanx View Post
    1. Of the logs I have done, I have noticed at most, a 3 point difference between the history and the running averages. Why is the History average better to use?

    :
    Running is the entire time you've been hooked up to data. History is the time you have been recording. Example: I watch data when warming up, but that is not good data to use for adjusting VE, when warmed up and driven a little I click record. History is whatever is recorded and also there is a history size you can set in the TP Value. $42 is set to 100 frames.

    Your issue by looking at your log real quick is is started when 60*f. Only use warmed up data for VE! Like half your log is not warmed up and I would not use that data for any VE adjustments.

    Quote Originally Posted by damanx View Post
    2. On the spreadsheet, specifically, what is the difference between the "new BLM with averaged tables" and "without"? Which is better to use?
    :
    Dave W will have to answer exactly what the average is?

    I copied his work into my spreadsheet and call it Course and Fine adjustments and I always use Course, which is without.

    Now you have to take into account the spreadsheet is also using VE1 table as 100%. SO if you still have numbers in your VE2? Well it is off by that amount in %.

    You should also have the Highway Lean Cruise ESC patch done. You can then disable the HLC by rasing the temp to max. But elimnating the ESC test disables the forced Knock at WOT PE which is a bad thing. First test adds 11* and if it gets no knock... like guys who run without knock... it adds 22*. Yes it's knocking by then and who wants a forced knock?

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    Now you have to take into account the spreadsheet is also using VE1 table as 100%. SO if you still have numbers in your VE2? Well it is off by that amount in %.
    So what I should have been doing was to add 30.8 to the table, zero out VE2 rpm's 400 through 3200?

    That makes sense.

    Guess it's back to square 1 on the ve tuning........

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    And set your Stoich AFR to 14.13...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
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    eagle mark do you mean he might have predetenation miss fire but no knock count?

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    Two logs from last night and this morning, (way to work and home) using the bin that ony fixed up:
    Attached Files Attached Files

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    damanx here is another bin that is from you 2 data logs history average, I going to try your original bin in my truck and see how it runs after I change it to a standard been.
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    damanx I tried your bin in my truck still thinking about it. try this bin going to work and home and data log it or a data log and a 10 second restart about the same distance back, it may run rich it is what I have been playing with in my truck 4.3i changed some things to match your auto bin my truck is a std trans. its aysn bin, my 4.3 likes them better I think it is the way ge designed the heads an intake is why they like aysn bins. mine likes a 288 ecm a lot more than a 747, even though you don't have as many things that you can adjust. if you get time try this bin.
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    Quote Originally Posted by ony View Post
    eagle mark do you mean he might have predetenation miss fire but no knock count?
    Just a missfire, decel and DFCO are leaner and harder to light off is why the timing is usually higher.

    Quote Originally Posted by damanx View Post
    Two logs from last night and this morning, (way to work and home) using the bin that ony fixed up:
    BLM tables were about perfect, what's the issue?

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    ps, my 64bit lap top shows less timming on all data logs than my 32bit desk top. this week end I will data log with my 32bit lap top to see if there is a problem with 64 bits, my old lap top has a screen going bad same adx but almost 5.7 degrezz timming differnts.all the bins I up load on this one may be corrupt. is any one else running a 64 an 32 bit system and seeing a different amount of timmimg with $42 5.2 adx?

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    Quote Originally Posted by ony View Post
    damanx here is another bin that is from you 2 data logs history average, I going to try your original bin in my truck and see how it runs after I change it to a standard been.

    Hey Ony,

    Joy for me as I had to replace the heater core in the truck this afternoon. Fortunately, it only took me about 2.5 hours from start to finish and I did not have to remove the dash to do it.

    In any case, I changed the stoich from 14.7 to 14.13 and drove that in last night. I noticed that the blm's went richer. On my lunch, I tweaked the ve table again and then drove that bin home.

    here is that bin with a data log.
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  15. #15
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    Quote Originally Posted by ony View Post
    ps, my 64bit lap top shows less timming on all data logs than my 32bit desk top. this week end I will data log with my 32bit lap top to see if there is a problem with 64 bits, my old lap top has a screen going bad same adx but almost 5.7 degrezz timming differnts.all the bins I up load on this one may be corrupt. is any one else running a 64 an 32 bit system and seeing a different amount of timmimg with $42 5.2 adx?
    That may explain the issues with my seeing different timing in TP and the timing analyzer showing actual crank timing.

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