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Car is STILL LEAN at WOT! LTFTs going negative at WOT! Please help!

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Old 05-27-2008 | 06:49 PM
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I'm pondering on mine 2. It's set to 12.99 AFR (1.13) up in the higher MAP areas. Could be causing an issue but I'm not sure. I was finally able to get down to 12.5 but quite honestly I couldn't tell you what all I've changed to get it there. I scaled the MAF higher and changed the PE numbers too.

My box is in the mail to HPTuners right now to get upgraded to Pro version. I'll sit on this until it gets back and see if changes in the OL EQ ratio affect anything. Let me know if you have any luck.

Also have a post going on HPTuners board asking for input. I'm working on a 98 LS1 and wondering if it's any different than 99+.
Old 05-27-2008 | 06:56 PM
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Originally Posted by crewchef
I'm pondering on mine 2. It's set to 12.99 AFR (1.13) up in the higher MAP areas. Could be causing an issue but I'm not sure. I was finally able to get down to 12.5 but quite honestly I couldn't tell you what all I've changed to get it there. I scaled the MAF higher and changed the PE numbers too.

My box is in the mail to HPTuners right now to get upgraded to Pro version. I'll sit on this until it gets back and see if changes in the OL EQ ratio affect anything. Let me know if you have any luck.

Also have a post going on HPTuners board asking for input. I'm working on a 98 LS1 and wondering if it's any different than 99+.
I'll definately let you know once I try it. I'm going to put my OLFA table back to stock and make a few runs. Unfortunately, as easy as that sounds, it may take a few days. I live in a conjested area and getting to an open straight road with no traffic isn't easy. Add to that a job, wife, and kid, and tuning the car comes in about 10th place. I guess that's why I sometimes look to others to find answers because I don't always have the testing, trial and error time I'd like to have. Thanks for your help and thoughts so far.
Old 05-27-2008 | 07:39 PM
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I'm still looking over my logs and I've noticed something else if this helps: The LTFTs seem to lock at 0 for a few seconds when I first go to WOT and then they go negative after that (while still at WOT). Then I quickly lift off the throttle to shift and get back on the throttle and the cycle repeats itself. The LTFTs lock at zero for a few more seconds and then go negative again. This pattern repeats itself in all four gears throughout the run. It's like it's going Open Loop at first and then falling out again.
Old 05-27-2008 | 10:49 PM
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Originally Posted by GC99TA
I'm still looking over my logs and I've noticed something else if this helps: The LTFTs seem to lock at 0 for a few seconds when I first go to WOT and then they go negative after that (while still at WOT). Then I quickly lift off the throttle to shift and get back on the throttle and the cycle repeats itself. The LTFTs lock at zero for a few more seconds and then go negative again. This pattern repeats itself in all four gears throughout the run. It's like it's going Open Loop at first and then falling out again.
Any throttle deviation when it does this cycling? For instance shift, then 100% throttle, then some sort of deviation off 100%. By dropping your OLFA table to 1.00 (telling it to add no more fuel) your always looking for stoich (or your desired VE setpoint) in those VE table cells. I think there is a table you've missed and it will come out pretty quick
Old 05-27-2008 | 11:57 PM
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stop wondering and spend $250 on a wideband so you can do it properly in an afternoon and you will then have a way to monitor it afterwards without your laptop. Really, trims are so much work and only good for down low anyway, you can't tune WOT with them. You can have your VE and MAF done in an hour with a wideband and then you can just command whatever you want in PE and get it.
Old 05-28-2008 | 02:38 AM
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Originally Posted by JoeyGC5
Any throttle deviation when it does this cycling? For instance shift, then 100% throttle, then some sort of deviation off 100%. By dropping your OLFA table to 1.00 (telling it to add no more fuel) your always looking for stoich (or your desired VE setpoint) in those VE table cells. I think there is a table you've missed and it will come out pretty quick
No, the throttle is completely too the floor. TPA shows 100% until I lift for the next shift. I agree......there is something I'm missing that is gonna slap me in the face when someone finds it..........
Old 05-28-2008 | 02:44 AM
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Originally Posted by Frost
stop wondering and spend $250 on a wideband so you can do it properly in an afternoon and you will then have a way to monitor it afterwards without your laptop. Really, trims are so much work and only good for down low anyway, you can't tune WOT with them. You can have your VE and MAF done in an hour with a wideband and then you can just command whatever you want in PE and get it.
I have a wideband......Innovate LC1. That is how I know for sure I'm going lean. I'm watching my guage (off and on) during the run and I'm also logging the voltage via my unused A/C pressure wire so I can reference it to all the other parameters I'm loggging like Trims, TPA, RPM, FTC...........

IMO, what I really need to do is spend $500 on HPtuners......but it's just not in the budget right now so I'm trying to make due with Autotap and LS1 Edit.
Old 05-28-2008 | 08:35 AM
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Adding to your MAF curve over 7-7.5k will add to your WOT if the PE commanded is off. You have everything you need to fix it. Log MAF frequency and your WB, where the WB deviates, the cell that corresponds with the frequency logged will need to be adjusted.
Old 05-28-2008 | 04:13 PM
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Thanks. That's generally how I've been tackling this issue, but so far I've seen no positive results. I keep scaling my MAF table higher in the freq ranges where it's lean but the AFR still keeps trying to jump back to the high 14 to low 15 range like its trying to stay around stoich at WOT. What really has me baffled is the fact that the trims are now going negative at WOT and pulling out the fuel that I have added via the MAF curve to keep it in that stoich range. When I first go to WOT they lock and zero and the AFR is in the low 12 range, but after a second or two they go negative and the AFR goes to around stoich. That can't be normal in PE mode. If the trims were staying zeroed out or even positive and I was lean, I would understand, but negative trims at WOT seem very odd.

Have you ever seen the OLFA table cause this kind of lean condition at WOT? I'm thinking that it could be to blame since I still have all MAP values above 60C set to 1.00. Everything I've read tells me that open loop fueling will always be based on the richer of the two values between the OLFA and PE vs RPM table, so technically the OLFA shouldn't be to blame since it's leaner at 1.00. However, I have also found a lot of info lately that say to always put the OLFA table back to stock after SD tuning and I didn't. However, that will be my next step in the process of elimination.

Any further insight on this is greatly appreaciated. I'll report back once I get a chance to test this out. Thanks again.
Old 05-28-2008 | 05:06 PM
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If your trims are negative and you are seeing 14s and up regardless of MAF scaling.... well, you are describing not going into PE mode. If your negative trims aren't settling to 0, you aren't in PE. And don't worry about your OLFA being 1 for now.
Old 05-28-2008 | 05:16 PM
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Can you take a second and post your bin? I know this has been said already but to me it just looks as if the PCM is not reverting to PE mode for some unforseen reason. The fact that your LTFT's are slipping into the negative is completley contradictary to the operation of the LS1 PCM (at least as far as I've come to know), so there's something esle at work here. Have you tried extreme changes for data purposes? Setting PE enabler to a very low point (20% TPS for example)?
Old 05-28-2008 | 06:00 PM
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Try setting it to never go into closed loop and see if that fixes it.
Old 05-28-2008 | 07:54 PM
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OK guys, I'm about 99% sure this problem is fixed! The curiosity was killing me, so I put my OLFA table back to stock, reflashed, and went out for a quick run. I didn't have time to make it to my full 1/4 mile run spot, but I was able to find a place to get in a quick blast all the way through 1st gear in half way though second. The log shows the LTrims locked at 0 at WOT and my AFR stayed between 11.9 and 12.1 Prior to this it would lean out after a few seconds in every gears.

I still want to make a full pass before I'm completely convinced, but for now I'm very happy I can't explain it, but it seems that having the OLFA table set to all 1s was keeping me from going into PE mode. Now I can start leaning my MAF table back out after adding all this fuel. Thanks for all your help so far and I'll be sure to post up once my tune is completely straight. I'm really trying to make it out to MIR on Friday but time is really against me.
Old 05-28-2008 | 09:15 PM
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Glad you got it figured out! Hope you make it to Budd's Creek this weekend! I used to live in Lexington Park some years ago, miss that area.

I'm going to take a look at those tables again myself but still think I've got a MAF issue going on. Hope my box is back sometime next week so I can get back to logging and quit guessing
Old 05-29-2008 | 12:14 AM
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Originally Posted by GC99TA
OK guys, I'm about 99% sure this problem is fixed! The curiosity was killing me, so I put my OLFA table back to stock, reflashed, and went out for a quick run. I didn't have time to make it to my full 1/4 mile run spot, but I was able to find a place to get in a quick blast all the way through 1st gear in half way though second. The log shows the LTrims locked at 0 at WOT and my AFR stayed between 11.9 and 12.1 Prior to this it would lean out after a few seconds in every gears.

I still want to make a full pass before I'm completely convinced, but for now I'm very happy I can't explain it, but it seems that having the OLFA table set to all 1s was keeping me from going into PE mode. Now I can start leaning my MAF table back out after adding all this fuel. Thanks for all your help so far and I'll be sure to post up once my tune is completely straight. I'm really trying to make it out to MIR on Friday but time is really against me.

Mine is 1 from 158degF and up, and while I'm tuning, it is on almost every car I tune until the VE and MAF are inline, and it has never kept one of them out of PE.

But I'm glad to hear that you are straight now.
Old 05-29-2008 | 09:15 PM
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OK guys.....updated report. It's time to eat a little crow, but at the same time I have great news......I think.

I rescaled my MAF table this evening and went out for a full 1/4 mile pass. The AFR went right to 12.9 and stayed there until about 6000RPM or so (basically a few seconds in each gear) before it went back to it's old trick of trying to go to stoich. Lift, shift, get back on it.......it goes back to 12.9 again for a few seconds and then back to 14.7ish. Son of a Bitch!

Well, I came home with my tail between my legs and started to think about any other possibilities that could be kicking me out of PE mode. Then I remembered that I occasionally set a code for high TPS voltage. I was wondering if this could be related to my WOT problem, so I did a few more searches on TPS voltage and holy **** look what I found:

https://ls1tech.com/forums/showthrea...oltage+max+tps

http://www.ls1tuning.com/iboard/index.php?showtopic=758

Both of these threads describe my problem to a "T"! I don't get the high TPS voltage code every time I make a run, but it does happen every now and then and has just been an annoyance I hadn't addressed yet. Anyway, I went out in the garage and tested my votage at WOT and got 4.78. So, I egged out the holes in the TPS sensor and adjusted it to 4.70 at WOT. I'm not gonna be quite as confident this time until I get a few full test runs, but damn, I think things look promising for me this time. I'll test it tomorrow and hopefully be headed to the track.
Old 05-29-2008 | 10:19 PM
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Cool
Old 05-31-2008 | 10:16 AM
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Alright guys, final update. My tune is 100% fixed. It was definately the TPS over-voltage causing me to be forced out of PE mode at WOT.

I went to the track last night and ran a new best of 11.37 @ 121.50......about a full MPH faster and 4 hundreths quicker ET. I still need to correct for weather for a true apples to apples comparison, but the weather seemed worse last night than it was when I went 11.41 @ 120.77 with my tune going lean.
Old 05-31-2008 | 10:28 AM
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Congrats on the new best and getting the tune figured out!
Old 05-31-2008 | 10:50 AM
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Originally Posted by crewchef
Congrats on the new best and getting the tune figured out!
Thanks man.... and I appreciate all the help and suggestions from you and the others. Sometimes it takes other peoples thoughts/ideas/suggestions to spur other thoughts and ideas.



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