possible problem with PLX WB02

[jfclubby]

:help2: When logging the PLX at some parts in the log it is measuring a constant AFR when sitting on a set throttle % but in other parts of the log it will cycle up and down from 16:1 to 14:1 under a similer throttle condition. was just wondering if this is normal, and was thinking that maybe the 12V power suply to the PLX module is not constant and in turn is causing this problem, would it help to wire in a 12V to 12V dc power regulator to give a constant 12V supply to the module. :cheers:

[hquick]

Hmmm...mine moves around a little but I'd only see the sorts of changes you're talking about during lean tip-in and rich decel.
You're not going into DFCO or...if running OLSD you're not hitting a semi open condition are you?

[jfclubby]

Hi Howard, this tune is in a VY series2 clubsport that is running MAFFLESS, How can i be sure that i'm not hitting DFCO or going into a semi open loop, and i'm not sure what lean tip in is. I was doing the auto VE and noticed it was not constant. Is a MAFFLESS tune always in open loop? Do i need to disable DFCO? and how do i do that?:cheers:

Regards James.

[hquick]

Hi James,
can you post a current tune and log?

[charcold-bowtie]

Closed loop will have some fluctation as it is chasing the 02's so to speak.

[jfclubby]

Hi Howard, Here is the log and tune that you asked for. :cheers:

[jfclubby]

Sorry Howard i forgot to upload the files, You will notice in parts of the log that the PLX goes from about 14:1 to 16:1 AFR when you have a steady throttle %. Maybe i have not set the tune up properly to do the auto VE, Note that my LTFT are disabled when doing this log. :cheers:

Regards James.

[hquick]

So...is that the tune you were using with that log...because the LTFT's and STFT's are enabled in that tune?
Or...are you saying that's your latest tune and the LTFT's were enabled after running that log?
Log looks pretty good to me. Looks like the O2's are trimming your fueling and you are definately going into DFCO.

See in the attached pic where your AFR goes to 19.6 and your timing goes to -2.5?
That's DFCO (decel fuel cut off). The second pic shows the 'sawtooth' look of your O2's switchingbetween rich and lean to try and hit 14.63 (14.7) you have in your commanded fueling table (B3647). Basically...everywhere you see 14.63 in that table is where your O2's are adjusting your fuelling.
There are alot smarter guys here than me so hopefully they will chime in but the log looks ok to me.

[hquick]

Oh...and you need to disable the LTFT's and STFT's for autoVE.

[JezzaB]

Looking at your tune. Its because you are in closed loop. To put the tune into open loop so you can do an AutoVE set:

B3801 to DISABLED
B3802 to 140oC
B4205 to 140oC across the board
B3647 everywhere it says 14.63 set to 14.5
B3636 to 140oC
B3313 to 140oC
A0014 1.00 across the board

That should do the trick ;)

Then look up what all of these things do.

BTW You might want to richen up the PE or Commanded AFRs up top a bit. With those that lean and the VE table low it could be very lean
Jez

[jfclubby]

Thanks Howard, yeah that was the latest tune and the fuel trims were enabled after that log. So the following tables need to be set to disable for the auto VE to work properly,
B3801, (LTFT)
B4205, (STFT)

And do I need to disable DFCO for auto VE by setting B3313 to max setting or am I fine to leave it as is?

Still trying to get my head around all this but i will get there.:grin:

Thanks Howard you've been a great help.:cheers:

Regards James.

[hquick]

No problem James....listyen to what Jez has to say....he knows ALOT more about this stuff than me.

[hquick]

You can either set the max temps for DFCO out of range so it never comes on or..just filter out TP% below say 5%.
If you do as Jez suggested...you'll be good to go.
You should use filters anyway...set up as per the AutoVE tutorial (open the tune tool..go to HELP>TUTORIALS and you'll find it listed in there).

[jfclubby]

Hi JezzaB, Thanks for the info yes it is a bit lean top end in the log i just fitted a set of 4 into 1 pacemaker headers to it and maybe that changed it a bit. Was running at 12.6:1 AFR on the dyno at WOT before the headers were fitted and now i'm trying to do the auto VE with the mod then go back on the dyno and retune the WOT fuel and timing, And as for the list of tables you have said to set for auto VE do they then need to be set back once finished. :cheers:

:rockon: Lots of helpful people on this forum :rockon:

Thanks heaps

[hquick]

I was just discussing this with Jez and we agree'd you're running a tiny bit lean...but I don't think it's an issue.
Run the AutoVE and that'll set it straight. Also...you get to learn something that way.
Any tables you don't know what they do...type in the Ref No. into the search box in this forum and start reading. Ask ALOT of questions.
Plenty of GOOD people here to help/share their knowledge.

[hquick]

Yes...you need to set them back once finished if you want to utilize STFT's/LTFT's as well as DFCO (all fuel saving really).
Or...you can just stay OLSD.
I'm presently still OLSD but want to go back to either CLSD or CLMAF once I have everything dialled in. Burb does run well in OLSD though.

[jfclubby]

Thanks guys, will attempt to make the setting changes after work tomorrow and give it another go. Should go ok now you have both set me on the right track, Will post to let you know how it went.:cheers:

Thanks again.

[JezzaB]

Thanks guys, will attempt to make the setting changes after work tomorrow and give it another go. Should go ok now you have both set me on the right track, Will post to let you know how it went.:cheers:

Thanks again.

Good stuff mate. You will have to check your timing once you do the autove as fuel and spark go hand in hand.

If it was me when you are finished. I would turn DFCO back on. Change all of the 14.5s back to 14.63 (still will make it use the O2s when ever it hits the cell with it in it) and leave lean cruise off but make it say 15.5 in the areas you cruise in (say 1200-1800rpm to 60kpa) this will make a nice lean cruise and should be very good on fuel. Raise the DFCO MAP pressure slightly so that you dont have to hit as much vacuum to enable it and set the RPMs slightly lower to help it kick in again earlier. Few other things but I wont spoil all of the surprises ;)

Jez

[jfclubby]

Hi Howard, Hi Jez, Like i said i would post to let you know how it went.
All i can say is AWSOME!!! I can not thank the two of you enough, No more crazy WB02 AFR's:hihi: Had a really good day completing the auto VE and enjoyed every minute of it, I learn't to set up the map filters properly to get rid of unwanted cells and the ones with low cell counts, done lots of driving under all throttle conditions to get the best possible average. Got 95% of the BEN map to the 1.01-1.02 mark as compared to the first log at around 1.10-1.20, Done the pasting into the main VE table then smothed the sharp peaks out, Made very slight changes to the Timing as I don't quite have a feel for it yet, Think this i better done on the dyno in controlled conditions where the ajustments can be seen better. I have enabled all the fuel trims and DFCO with the ajustment that you pointed out, Now i will log fuel trims during the week, Fingers crossed should be good.:cheers:
hope you both can assist me with future modifications/problems.

Regards James.

[hquick]

Great news James.
Makes things so much more enjoyable when it goes well and you feel like you're getting somewhere.
Also...you're absolutely right about sorting the timing on a dyno.