Thread: Lean LTFT!

Page 1 of 2 12 LastLast
Results 1 to 20 of 24
  1. #1 Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Ive been chasing this problem for about a month now and i cant figure out why my LTFT are pegging at 16.4 during cruise. What I did so far is a vacuum gauge test and its holding at about 20 in/hg so a vacuum leak is not my problem. Changed fuel filter, MAP and both O2 sensors with same problem with LTFT. At idle my LTFT hangs between 0.0 and -3.2 but anytime i give it any gas it jumps right to 16.4 and stays there until i let off the gas and at WOT it locks in at 14.8. I first discovered this problem when i saw i was getting KR at freeway speeds and when i checked for LTFT they were pegged at 16.4 and not moving. Ive had all my mods listed below for a good 6 months problem free and then this problem appeared. Im beginning to think that my PCM wasnt right from the beginning and it just took the temperature to rise for me to see my KR im getting now because all the mechanicals seem to check out fine.
    When i first decided to buy a pcm all i wanted to do to the car was downpipe, CAI and a 3.5 so thats what i got it tuned for. My plans changed when my uncle gave me a set of headers and with that i dropped to a 3.4. Would adding these two things through my tune this far off? Any ideas would be great!
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  2. #2 Re: Lean LTFT! 
    TDCRacing
    Guest
    You need a MAF tune to start with. That should fix the problem right there.
    Reply With Quote  
     

  3. #3 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Im unable to tune which is why i have a programmed pcm.
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  4. #4 Re: Lean LTFT! 
    GTP Level Member Scimmia's Avatar
    Join Date
    Jun 2008
    Location
    QCA, IA
    Posts
    1,054
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    do your headers leak?
    2001 Buick Regal LS - Almost Stock
    Reply With Quote  
     

  5. #5 Re: Lean LTFT! 
    TDCRacing
    Guest
    Quote Originally Posted by Lumpo View Post
    i have a programmed pcm.


    Which is why you have the trims like you do. It's very hard to get trims in line without having a custome tune on the car. Ambient temps as little as 10 degrees difference will cause your trims to be off.
    Last edited by TDCRacing; 06-17-2009 at 10:06 PM.
    Reply With Quote  
     

  6. #6 Re: Lean LTFT! 
    Donating Users Lawngoose's Avatar
    Join Date
    Dec 2007
    Location
    Outer Space
    Posts
    1,250
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    if vac is fine ... then check for exhaust leaks.
    02 GTP 13.6 @ 100mph - SOLD
    Reply With Quote  
     

  7. #7 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    I dont have a vacuum leak or an exhaust leak.
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  8. #8 Re: Lean LTFT! 
    TDCRacing
    Guest
    Quote Originally Posted by TDCRacing View Post
    Which is why you have the trims like you do. It's very hard to get trims in line without having a custome tune on the car. Ambient temps as little as 10 degrees difference will cause your trims to be off.
    Again...
    Reply With Quote  
     

  9. #9 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Im just trying to figure why i went from having 0 KR to having up to 5* of KR at freeway speeds when i changed nothing. When i started reading KR on my aeroforce i switched it to view LTFT and they were pegged at 16.4 and not moving. Now this could have been like this from the beginning since i never had a reason to scan LTFT since the car was running great but i definantly see a problem now. I have a guy nearby who is willing to tune my car but i find its hard to believe its the tune since the car was fine one day and KR the next.
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  10. #10 Re: Lean LTFT! 
    GTP Level Member Scimmia's Avatar
    Join Date
    Jun 2008
    Location
    QCA, IA
    Posts
    1,054
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Yeah, unless the tune is absolutely horrible, I don't see it just pegging the LTFTs like that. Bad MAF, maybe? How do your MAF frequencies look?
    2001 Buick Regal LS - Almost Stock
    Reply With Quote  
     

  11. #11 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Ill have to take a look tomorrow where should they be? I have a Mac Mentor so im able to read alot of parameters i just dont know where they should be. So any help on what to check and where the numbers should be would be great.
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  12. #12 Re: Lean LTFT! 
    GTP Level Member Scimmia's Avatar
    Join Date
    Jun 2008
    Location
    QCA, IA
    Posts
    1,054
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    The main things I would look for is nice linear scaling, and staying fairly constant during cruise. There are a few things that can screw up the MAF reading, contamination from over oiling a gauze filter (like your K&N) or removing the screen in the TB, for example. At times, they just go bad, as well.
    2001 Buick Regal LS - Almost Stock
    Reply With Quote  
     

  13. #13 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    MAF Frequencies...

    Idle: 2800-3000
    Cruise with LTFT 16.4: 3800-4000
    WOT: Around 8000
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  14. #14 Re: Lean LTFT! 
    Donating Users Lawngoose's Avatar
    Join Date
    Dec 2007
    Location
    Outer Space
    Posts
    1,250
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    To me your MAF looks fine.

    If your are 100% positive that you don't have vac/exhaust leak. Then it looks like you may fall into the 01+ Fuel Dump Issue. Sure fire way to test is to put 00 or below BIN file on your PCM.

    Read this. It may apply to you, if you have done something to your rear 02 sensor.

    http://www.grandprixforums.net/f65/r...highlight=ltft
    02 GTP 13.6 @ 100mph - SOLD
    Reply With Quote  
     

  15. #15 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Nothing done to the rear O2 im still running both O2's.
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  16. #16 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    I welded up my EGR the other day but at cruise my LTFT still seem high hanging at 10.1 which is a little better than 16.4. I did notice that all my KR is gone since my LTFT came down so im happy about that but still would like it to come down some more. Is it normal for an off the shelf tune to be like this with these high LTFT? Am I going to harm my car if i leave it be or do i have to do something about this?
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

  17. #17 Re: Lean LTFT! 
    GT Level Member DOUGLASMELTER's Avatar
    Join Date
    Apr 2009
    Location
    ERIE
    Posts
    370
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    so here is a question then....since temp can throw my trims off so much then should i have a bin file for every type of driving weather? say, one for every ten degree temp difference?
    Reply With Quote  
     

  18. #18 Re: Lean LTFT! 
    TDCRacing
    Guest
    YES! You hit the nail on the head with that one.
    Reply With Quote  
     

  19. #19 Re: Lean LTFT! 
    Donating Users Lawngoose's Avatar
    Join Date
    Dec 2007
    Location
    Outer Space
    Posts
    1,250
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    I personally keep a winter/summer bin.

    But I had the 16.4 issue with no vac/exhaust leaks... and I sent it to a friend to hex edit the catalyst diag test it kept running. That fixed mine.
    02 GTP 13.6 @ 100mph - SOLD
    Reply With Quote  
     

  20. #20 Re: Lean LTFT! 
    SE Level Member
    Join Date
    Jun 2009
    Location
    Milwaukee
    Posts
    46
    Thanks (Received)
    0
    Likes (Received)
    0
    Dislikes (Received)
    0
    Well i decided to swap out my MAF with my dads car who also has 1998 GTP to see what would happen as suggested by another member. Well first my car only got half boost and my tranny started shifting really strange. Another thing is that it started running way rich going to about -20 where as my other MAF was hanging around 10.1. Whats the deal with this????
    2003 Galaxy Silver Limited Edition GTP
    Mods: 2.8 MPS | S2IC | XP CAM | GEN V | 65# | E85 | TOGS | N* TB | HPT PRO | Impala Brakes | BUILT TRANS w/3.29 GRS
    23° Timing...12.0 AFR...356 WHP
    Reply With Quote  
     

Page 1 of 2 12 LastLast

Similar Threads

  1. Vac leak LTFT?
    By Sabrewings in forum PCM Tuning
    Replies: 12
    Last Post: 04-15-2009, 05:42 PM
  2. Lean?
    By Deeter in forum PCM Tuning
    Replies: 12
    Last Post: 09-17-2008, 05:11 PM
  3. Why LTFT, when STFT should be quicker
    By IndeedSS in forum PCM Tuning
    Replies: 5
    Last Post: 08-26-2008, 08:27 AM
  4. lean condition code
    By TDCRacing in forum PCM Tuning
    Replies: 11
    Last Post: 05-06-2008, 07:12 PM
  5. 940 WOT o2 is lean?
    By Bio248 in forum PCM Tuning
    Replies: 19
    Last Post: 03-04-2008, 05:55 PM
Tags for this Thread

View Tag Cloud

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •