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Thread: Missing while accelerating - not WOT

  1. #1
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    Default Missing while accelerating - not WOT

    Hello guys, I have a miss while i'm accelerating....it is not one dead miss but multiple slight misses while i'm under light-medium throttle (not in boost). I have attached a log of it occuring a couple times (starting at frame 1674 and again at 3240). What do you recommend that i log to find the culprit? I also included my tune. p.s... the idle is a mess but i'm about to start on that.

    Log_0016.efi
    geoff original.tun

    Any help would be great, thanks!
    Last edited by Tracyrr; August 2nd, 2011 at 06:18 AM.

  2. #2
    Joe (Moderator) joecar's Avatar
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    I am out of town this week so I can't view the files... when it misses what does the commanded AFR say and what do the LTFT say...?

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    i tried more fuel and it didn't seem to help. I pulled timing and it seem to get worse so i added it back. I think i have a valve float issue (seperate issue) over 5000 rpm's so i will tackle that and update next week if my light acceleration miss still persists. I will log the ltft. thanks for taking the time.

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    Log_0033.efi
    geoff original.tun

    Ok, i changed my valve springs so now back to the orignal problem. I logged the LTFT's today with the log included and i also included my latest tune. It missed pretty bad from around frame 4020 - 4045ish... i blipped the throttle a few frames later so i would know where to find it on the log so please ignore the spike at around 4060. I forgot to include the spark advance on this pid but it is normally in the upper 20's to lower 30's while cutting up at part throttle. Thanks joe, any info would be very helpful. Tracy

  5. #5
    Joe (Moderator) joecar's Avatar
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    I'm looking at your files, I don't see anything yet...

  6. #6
    Joe (Moderator) joecar's Avatar
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    At frame 4036 the wideband shows a lean spike... and DYNCYLAIR and DYNAIR don't look right compared to MAP, this means maybe your VE table is not right...

    your VE table has rift's in two directions right about where the frames you mentioned produce the crosshairs in the VE table:

    Click image for larger version. 

Name:	VE table is suspect.png 
Views:	261 
Size:	189.3 KB 
ID:	11697
    Last edited by joecar; August 16th, 2011 at 03:57 AM.

  7. #7
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    Yes, that is a big spike alright.... I'm new to tuning, you are saying that my fueling table is goofed up or my AEM wideband is not accurate? Sorry if a stupid question I forgot to mention that this is a twin turbo car if that makes a difference. Thanks so much

  8. #8
    Joe (Moderator) joecar's Avatar
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    You can sanity check your wideband by commanding CL or SOL and seeing if the wideband reports lambda 1 and stoich AFR.

    BTW: in B3647 any cells that are stoich will trigger SOL which uses STFT's to trim to stoich, watch out for this when correcting the VE table.

    The VE table is not right with that ridge and the hole adjacent to it.

  9. #9
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    Quote Originally Posted by joecar View Post
    At frame 4036 the wideband shows a lean spike... and DYNCYLAIR and DYNAIR don't look right compared to MAP, this means maybe your VE table is not right...

    your VE table has rift's in two directions right about where the frames you mentioned produce the crosshairs in the VE table:

    Click image for larger version. 

Name:	VE table is suspect.png 
Views:	261 
Size:	189.3 KB 
ID:	11697
    If i understand you correctly, you are speaking of the big changes in fueling around the "cross" on the table? I think i will just go back to my original ve fueling since i chopped this one all to hell....lol

    Quote Originally Posted by joecar View Post
    You can sanity check your wideband by commanding CL or SOL and seeing if the wideband reports lambda 1 and stoich AFR.

    BTW: in B3647 any cells that are stoich will trigger SOL which uses STFT's to trim to stoich, watch out for this when correcting the VE table.

    The VE table is not right with that ridge and the hole adjacent to it.
    I check my wideband via my efilive software or my AEM gauge? Can you tell me what CL and SOL are? Sorry for all of the question but this is really a huge help!! Thanks tracy
    Last edited by Tracyrr; August 16th, 2011 at 04:48 AM.

  10. #10
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    geoff original.tun

    Wow, the original VE fueling (boost and non-boost) look so much better.... After i make changes, i obviously need to take a look at the graph to make sure there are no rifts/holes.... lol....
    Last edited by Tracyrr; August 16th, 2011 at 04:56 AM.

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