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lean issue need HELP

This is a discussion on lean issue need HELP within the General Help forums, part of the LSx Technical Help Section category; Okay, so had car set up for tuning the ve.... open loop speed density. out of no where the car ...

  1. #1
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    lean issue need HELP

    Okay, so had car set up for tuning the ve.... open loop speed density.


    out of no where the car started to run lean...like maxing out my afx wideband (16afr).

    now tried tracking down vacuum leaks, cant find any. rechecked my intake manifold bolts, new pcv line, checked header bolts, tried some old tunes and wasnt the tune.

    Seems to do it in mostly in idle, and cruising. seems to be about a 15.8afr until i put it in gear then its maxed out.

    running lean in both banks, so its not just once side.

    I cant see anything cracked after the maf.

    umm im tired, can think of what else ive tried as of now.

    Im not really sure what to check, im sure im over looking something.

    Could it be the IAC...the car seems to surge when in openloop speed density...as in the idle climbs then drops and repeats. not so much with the o2 sensors and maf turned on.

    also with the maf and even just the o2 sensors turned on, according to the wideband it fights to get to stoch so its not the wideband.


    Like I said any help or directions to look at would be helpful, and I'm sorry I'm tired and didn't lay the information out the best, but I'll go through it in my head at work tomorrow and add anything I forgot.

    Thanks

    btw its a 99 ls1 in a TA

  2. #2
    Smiles for 9.5 Years cammed goat's Avatar
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    What are your modifications other than the headers? Is the Check Engine light on right now? If so, what codes are you getting? If you suspect IAC, pull it and check to see if the gasket is torn along with any carbon on the pintle and inside where the IAC goes. Get back to us as soon as you can. I was initially going to suggest cleaning the MAF, but you are running SD so that kills that theory.

  3. #3
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    Quote Originally Posted by cammed goat View Post
    What are your modifications other than the headers? Is the Check Engine light on right now? If so, what codes are you getting? If you suspect IAC, pull it and check to see if the gasket is torn along with any carbon on the pintle and inside where the IAC goes. Get back to us as soon as you can. I was initially going to suggest cleaning the MAF, but you are running SD so that kills that theory.
    Ls6 intake, headers, emissions delete.catch can (was doing it before)

    I know the iac is broke now, but when I first took it out there was the plunger but nothing covering the spring and some carbon.new one should be here today.
    Just wasn't sure if the iac could cause that, the idle doesn't seem to be high for an air leak.


    Just getting frustrating because I want to get it tuned.got beat by my cousins modded 06 stang by .07 seconds now he thinks its untouchable

  4. #4
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    Oh no check engine light, going to pull the tb and clean it all out when I put the new iac in.

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    new IAC in...the count is low like 32 at idle, so I need to figure out how to reset that and adjust the TB...well find the screw.

    In openloop speed density still going lean.

    one thing I found that is odd is in idle is 15.6-15.8., put in gear the idle drops then climbs back up...afr goes to 16(max on sensor).
    Noticed though everytime I change gear on the selector the idle drops down a few hundred then climbs back up....doesn't matter R to D, or 1, 2,3,D,3,2,1. does it every time.

    So still back in square one still. The counts keep the same in idle and drive...like they don't seem to be adjusting for a vacuum leak.

    im totally lost at the moment

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    In order to adjust your VE tables you have to disable certain functions. Are you sure you set it up correctly? Also, what happens if you plug the MAF back in? You are setting it up to run in SD mode, so I assume you either disabled the MAF or unplugged it.

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    Quote Originally Posted by pajeff02 View Post
    In order to adjust your VE tables you have to disable certain functions. Are you sure you set it up correctly? Also, what happens if you plug the MAF back in? You are setting it up to run in SD mode, so I assume you either disabled the MAF or unplugged it.
    I am tuning it using the set up from looking at ls1 tuning guide. I have the maf and the o2 sensors disabled, all the fuel modifiers should be disabled, and the maf is unplugged just to be safe.

    with either the o2 senors on or both the maf and o2 sensors (haven't just tried maf) it finds its way back to stoch.


    Today I got ambitious. I took my tune and in the ve tables I changed the 800rpm column from I think 25 or 30 to 45 kpa. I added about 7% to those cells. That got me pretty close to where I wanted and I was all happy. So I went on a 17 minute drive, did some logging. Changed the table via lambda error, drove home. Everything was about dead on. Fixed a few spots and flashed the pcm before I went in the house, but I double checked to make sure the car started and wanted to see it at about stoich again(I was getting happy) what do you know, it was leaning out again, so I put it in gear because that's when it does it the worst (gear at a dead stop) which is 800rpm at 45kpa. Changed the table again, nothing really, took it for a drive and the other cells were pretty close still.

    Now this got me thinking, so I was watching again at idle because I think it was up to a VE of 75 @800rpm and 45kpa which was waaaay to much. I had noticed the Idle wanting to go and work its way up when it was in gear, and using the display that came with the ngk afx (most people call worthless and un needed because it reads 14.5 when its really 14.7) it would go from about a 14.1/14.3 to almost 16 when the idle increased. I also was logging in hptuners at the time, and was watching the commanded and actual IAC counts. When the AFR was good it was at about 70-80, but when I dropped it in gear they would go up to 160-170 and then it would start running lean again. If I go out driving around it would stop at 60-70 counts because it wasn't at idle and when I would stop afterwards it would be back down to a 14ish AFR.

    So now I am thinking I need to do a IAC and TB position sensor reset, and I am thinking I need to adjust the screw for the tb blade to get the counts back down to normal?????

    I think I seen somewhere that at idle its suppose to be around 70 counts correct?

    Its weird though, sometimes it does it then goes away for awhile.

  8. #8
    Smiles for 9.5 Years cammed goat's Avatar
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    Try the IAC reset and get back to us.

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    when you hook the O2's back up where are your LTFT's at? What does your afr look like when you're driving around and did you disable DFCO when you put it in OLSD? Are you logging your wideband with hptuners? Have you verified that it's logging correctly? Most widebands I've ever tuned with I had to adjust the ground offset on at least a little to get them to read the same.

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    I have been really busy the past few days, so I haven't messed with it. The issue seems to have gone away for the most part (fingers crossed for saying that), because watching the afx display it seems to go rich now almost all the time idle and driving. So when I get some time and its nice out (raining in ohio right now) Ill play around with the fueling some more.

    I spent a lot longer the other day doing a wideband install write up, because when I installed mine a few months ago it was a pain to track down all the information on where to run it and how to wire it up. I think it was a good evening spent.
    Its in the tuning section under "permanent wideband install, lots of pictures"

    Ill definitely post back when I figure out if I have it fixed or not. It did this awhile back where the lean issue went away for a few weeks then came back out of no where. So I'll see what happens.

    Oh and I haven't messed with the IAC reset, the idle seems to be figuring itself out because it doesn't go up and down as bad anymore...so im going to let that play it self out for awhile to see what happens.

  11. #11
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    Quote Originally Posted by 0rion View Post
    when you hook the O2's back up where are your LTFT's at? What does your afr look like when you're driving around and did you disable DFCO when you put it in OLSD? Are you logging your wideband with hptuners? Have you verified that it's logging correctly? Most widebands I've ever tuned with I had to adjust the ground offset on at least a little to get them to read the same.
    They were negative I believe.(raining now and don't feel like going out driving). Currently its running rich driving, DFCO should be disabled. I am logging it with hptuners, and when I first started to log at 16 afr I was only reading 1.07 instead of 1.10 lambda, so I wasn't getting the full 5v at max, so I compensated it by adjusting my formula so it was correct. I seen the issue during all the research I was doing before the wb install so that was one of the first things I looked for, and was one of the first headaches to figure out at first.

  12. #12
    Veteran 0rion's Avatar
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    I did a write up when I installed my LC-1.....it's stickied here in the general section under tech info. Where at in Ohio are you?

    LC-1 install

  13. #13
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    Quote Originally Posted by 0rion View Post
    I did a write up when I installed my LC-1.....it's stickied here in the general section under tech info. Where at in Ohio are you?

    LC-1 install
    I think I remember seeing your write up when I was researching for mine, but I couldnt do that since of the huge plugs on the afx. Maybe I can get mine stickied too lol

    I am about 40 or so minutes south of toledo, I see your from ohio too where are you?

    Permanent Wideband Install Write Up, Lots of Pictures

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