Missing while accelerating - not WOT

[Tracyrr]

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.

11544
11545

Any help would be great, thanks!

[joecar]

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...?

[Tracyrr]

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.

[Tracyrr]

11695
11696

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

[joecar]

I'm looking at your files, I don't see anything yet...

[joecar]

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:

11697

[Tracyrr]

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

[joecar]

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.

[Tracyrr]

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:

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


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

[Tracyrr]

11700

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....

[joecar]

No worries... :)

CL = closed loop
SOL = semi open loop (cells in B3647 set to stoichiometric AFR)

[joecar]

When you make changes to the VE, look at the "trend" of the change, if it is consistent then carry this trend onto the cells that were not hit (i.e. bring them up or down by roughly the same percentage as the trend).

Ripples in the VE are ok.

Cliffs, spikes are not ok.

[Tracyrr]

oh, i guess i should have mentioned that this is an SD tune. Joe, you have been a huge help!! I'll update soon, thanks tracy

[Tracyrr]

hey joe, all fields are 14.63 except for 95 and 100 kpa which are 13.81 and 12.50 respectively. So if i understand this correctly (i may be dead wrong), my non-boost fueling should attempt to follow B3647...unless in PE mode....

[joecar]

In B3647 any cells that have the same value as B3601 will trigger SOL (which used STFT's to trim to that cell)... when logging with the intent to correct the VE table you must first set these cells to some other value (i.e. slightly different than what B3601 contains).


Yes, correct, if you're running in OL, then commanded fuel should follow B3647 unless PE enables (in which case it should follow B3618).

[Tracyrr]

Now efilive is starting to "click" for me....! Finally.... Thanks Joe!!

[joecar]

No worries :cheers:

More info, see post #4 here: Summary-Notes (http://forum.efilive.com/showthread.php?14188-Summary-Notes)

[Tracyrr]

Joe, YOU FIXED MY CAR!!!! It runs awesome now in transition...! I'm so pumped. Thanks a bunch man!! tracy

[joecar]

Hey cool :cheers: no worries :)