Page 2 of 9 FirstFirst 123456 ... LastLast
Results 21 to 40 of 179

Thread: Perplexing PLX !!**??

  1. #21
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by Dirty Howie
    Scott please confirm these Editor tables and the config before I start.

    Not sure I understand this....."before you star logging...make the #'s in your Closed Loop vs Airflow Mode tables read
    0,2,4,6,8,10,12,14,16,16,16,16,16,16............." Mine were different but I changed them as requested. Will I be changing this back???



    DH
    you can...but I wouldn not
    it gets very complicated to make the airflow modes work well at a stock value as they cause a blending of the 2 values its inbetween...
    it can be done..its just easier and simpler to make them all jive with the centering values of teh o2 switchpoints and leave them like that
    -Scott -

  2. #22
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Quote Originally Posted by soundengineer
    you can...but I wouldn not
    it gets very complicated to make the airflow modes work well at a stock value as they cause a blending of the 2 values its inbetween...
    it can be done..its just easier and simpler to make them all jive with the centering values of teh o2 switchpoints and leave them like that
    I don't think you confirmed my config and preset tunes. If it all looks good I just need to remember to reset the fuel trims with VCM Control before each log.........

    If I don't crash or blow up my car at the track (WSIR) tomarrow I will do this teusday on my way to and from work.

    Thanks,


    Dh

  3. #23
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by Dirty Howie
    I don't think you confirmed my config and preset tunes. If it all looks good I just need to remember to reset the fuel trims with VCM Control before each log.........

    If I don't crash or blow up my car at the track (WSIR) tomarrow I will do this teusday on my way to and from work.

    Thanks,


    Dh
    just log the stuff I listed above...nothing more...nothing less
    -Scott -

  4. #24
    Tuner in Training sixvi6-camaro's Avatar
    Join Date
    Apr 2007
    Posts
    17
    well my car has a lean reading 15.0-15.4 PLX WB in CL at 14.7 cruise as well but... my car has next to no mods though.. Its got a lid, catback, built trans 3600 stall, 3.73 rearend... its on stock manifolds, cats, and y-pipe.
    I'm siming bank 2 NB though and for sure its off because the LTFT's on bank 2 are always more negative than bank 1. I've gone through and checked for air leaks loose plugs and have found nohitng. On my last log I exported the data to excel and I took all the NB readings on B1 and B2 when in crusie comanding 14.7 and averaged them. B1 averaged 473 and b2 512. I still believe the PLX is off by a lot. If I change the switchpoints in HPT to offset PLX by the % its off now I guess it would bring my CL 14.7 readings into where they should be but I dunno if I can trust this PLX regardless.

    If I have the money after the Power tour I think I'll pickup an LC1 or possibly an AEM or WMS looks kinda decent too and swap out the PLX.
    Last edited by sixvi6-camaro; 05-27-2007 at 12:01 PM.

  5. #25
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    lid alone is enought to change the engines heat range on some engines....
    totaly depends on how much better the parts let the air flow...
    plus catback allows exhauts gasses toget out differently as well...
    every little mod adds up and changes the heat range
    -Scott -

  6. #26
    Advanced Tuner flea's Avatar
    Join Date
    Aug 2006
    Location
    Illinois
    Posts
    242

    Any comments on MAP???

    I'll still not sure what to make of this one. Gone back and forth several times to make sure I'm not missing anything and MAP always goes up when I go back to CL. The MAP at idle has ALWAYS been ~40-41 KPa.

    Quote Originally Posted by flea
    Thanks Scott, I'll forward the data over the next day or so.

    One more odd thing I forgot to mention.

    MAP has always been around 40-41 KPa at idle [550 rpm] (before and after the mods). When I re-enable CL all of the sudden I'm logging 45-46. I scratch my head a few times and go back to OL ....... MAP is right back to 40-41. What am I missing here?
    Flea
    --------------
    2006 GTO
    Kooks LTs, NGK WB
    12.96 @109.12

  7. #27
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Went to the track yesterday and obviously there wan't too much cruising
    But just for interest here are the AFR Histos and logs if anyone wants to compare. Temps were in the high 80's in first log and 90's in second. Speeds range up to 139 mph.........

  8. #28
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Just loaded up Scotts config. and put the OL tune in her.

    Scott should I wait for temps to come up or start from idle or does it matter???

    Post results tomarrow nite ........


    DH

  9. #29
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by Dirty Howie
    Just loaded up Scotts config. and put the OL tune in her.

    Scott should I wait for temps to come up or start from idle or does it matter???

    Post results tomarrow nite ........


    DH
    best to be at full operating temps just like anytime you tune
    -Scott -

  10. #30
    Супер Модератор EC_Tune's Avatar
    Join Date
    Apr 2003
    Location
    Almost 2000 feet.
    Posts
    7,876
    I will definitely beg to differ (at least on the PLX's I have experience with) that the o2 sensors don't care as long as they are at an appropriate temperature for switching.

    No matter how hot they get (or cold) the switchpoint is still 14.6x AFR for gasoline motors (lambda 1.0).

    The "range of operation" changes significantly with temperature (hot = 0-890mv colder 0-1100mv). But the switchpoint remains the same. Otherwise the OEM's would have HUGE issues with calibration drift from vehicles operated in North Dakota in the winter compared to vehicles operated in Tuscon in the summer.

    Here's a thread I posted years ago about O2 sensors and NGK's site a few other sites, GMI, and one from Algor
    Always Support Our Troops!

  11. #31
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by EC_Tune
    I will definitely beg to differ (at least on the PLX's I have experience with) that the o2 sensors don't care as long as they are at an appropriate temperature for switching.

    No matter how hot they get (or cold) the switchpoint is still 14.6x AFR for gasoline motors (lambda 1.0).

    The "range of operation" changes significantly with temperature (hot = 0-890mv colder 0-1100mv). But the switchpoint remains the same. Otherwise the OEM's would have HUGE issues with calibration drift from vehicles operated in North Dakota in the winter compared to vehicles operated in Tuscon in the summer.

    Here's a thread I posted years ago about O2 sensors and NGK's site a few other sites, GMI, and one from Algor
    less than 100* IAT is not enough to cause drift...
    its exhaust temps that cause it....
    and it does drift quite a bit with even a few hundred degrees difference in EGT

    and again..were not talking about the PLX being wrong...were talking about the stock O2's being wrong because of mods...
    widebands are a difference breed and dont have the same issues as the narrowbands do

    also...with that being said...
    where is the actual switchpoint on a stock O2 supposed to be.and why does GM not have that in every cell in the o2 switchpoint table???
    if it switched always at the same spot that was supposed to = lambda 1.0 then we wouldnt have a switchpoint table at all....
    Last edited by S2H; 05-29-2007 at 12:47 PM.
    -Scott -

  12. #32
    Супер Модератор EC_Tune's Avatar
    Join Date
    Apr 2003
    Location
    Almost 2000 feet.
    Posts
    7,876
    The switchpoint table is a biasing method. GM wanted the car to idle richer by a tenth or so so they moved the switchpoints up. Remember switchpoints are only a biasing method. And notice that all LS2's are at 451 across the board. Most later LS series trucks are 451 across the board as well. GM "adjusts" things to keep emissions under control as emissions and warranty are their primary goals.

    IAT plays no roll in switchpoint. The only other thing that can affect o2 operation is whether you have an effective heater element in the o2 sensor (or a blown o2 fuse!). If the o2 is located poorly (seeing 1 cylinder instead of 4) you will have problems. I have seen that way too many times. However if the sensor is located properly and has an effective heater you won't have problems with drift. Cheap widebands will give you erroneous results period.
    Last edited by EC_Tune; 05-29-2007 at 01:09 PM.
    Always Support Our Troops!

  13. #33
    Senior Tuner 5_Liter_Eater's Avatar
    Join Date
    Nov 2005
    Location
    Houston, TX
    Posts
    3,968
    This blows. We have two very experienced tuners; one who took the same WB that read ~15.5 on modded cars and ut it on a stock car and it read 14.7; and another who swapped WB's on the same car and went from ~15.5 to 14.7. I feel like Johnny 5; need more input.

    Honestly I don't mind cruising at 15.5:1 but if my WB is off when cruising, who's to say it's not off at WOT.
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game

  14. #34
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Here is a log I did today in OL as requested by Scott

    *****I FORGOT TO RESET FUEL TRIMS******* (but will and log again on the way home.

    I briefly have time to look at this log but noticed that my commanded at cruise is 14.2 instead of 14.68 where its always been before.


    DH

  15. #35
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Okay....remembered to reset fuel trims. This is Open loop.

    Will log closed loop tomarrow.


    DH

  16. #36
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Well here is today back to Closed Loop ....... look at those AFR's up in the 16's !!!!!

    Scott: please let me know if you want more logs and that everything was done as requested.

    In OL my commanded AFR is 14.12 ?????? In CL it is 14.87 in the non PE range.
    Can anyone expalain this........


    DH

  17. #37
    Senior Tuner Russ K's Avatar
    Join Date
    Dec 2005
    Location
    Regina, Sask.
    Posts
    4,213
    Howard,

    Sounds like your open loop table isn't at 1.00 at operating temp, or the stoich AFR is not at 14.68. Looks like your wideband is reading leaner than ever now!

    Russ Kemp

  18. #38
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Quote Originally Posted by Russ K
    Howard,

    Sounds like your open loop table isn't at 1.00 at operating temp, or the stoich AFR is not at 14.68. Looks like your wideband is reading leaner than ever now!

    Russ Kemp
    Russ

    The only thing I changed since the last time you looked at my tune is what Scott recommended........"before you star logging...make the #'s in your Closed Loop vs Airflow Mode tables read
    0,2,4,6,8,10,12,14,16,16,16,16,16,16............."

    This is my current tune.

    The TUNES in the above post are with the table adjusted and trims set for logging as Scott requested.


    DH

  19. #39
    Not A Tuner
    Join Date
    Oct 2006
    Posts
    977
    Here is the ride back home today where the temps were a little warmer and the AFR 16 instead of 16.6

    So what can be gleaned from these logs????? Are the 02's working correctly????

    Does anyone want to change their opinions of the PLX being bad

    Scott..............


    DH

  20. #40
    Subscribing.