not to throw a wrench into this whole negative Ltrim = 0 WOT ltrim but..
09-14-2004, 10:32 PM
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not to throw a wrench into this whole negative Ltrim = 0 WOT ltrim but.. ive had my trims negative using IFR and after some reading I decided to set my IFRs back to stock and modify my VE tables. I set IFR back to stock and have driven about 50 or 60 miles and logged. My Ltrims are now +2 or so everywhere BUT even w/ a 13.5 or so AFR (havent messed w/ PE again yet after IFR change)I'm getting zero knock when I used to be able to generate it when I wanted to and my Ltrims are still going to 0 at WOT.. On top of this, my car used to sometimes go to 300-400 rpms as i would come to a stop. This no longer occurs. SO what gives here? This seems to be the complete opposite of what i have read should be happening. It also seems that on tranition airflows, my o2 voltages arent dropping to the double digits and staying there as long as they would before i changed the IFR back. I will post some screen shots of my Ltrim historogram in a bit.
Input please?
Dave
Input please?
Dave
09-14-2004, 10:48 PM
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I don't know. I noticed something similar to that while I was tuning. That's why I stopped using the IFR table. I could tell something was wrong, but I wasn't sure what. I still think most of the problems people are having are fueling issues. I would imagine if you set your IFR table to put your trims negative it would have two effects:
1) Richen your MAF determined fuel mixture, negating some of the effects of a lid.
2) Act the same as adding 10 percent to your VE table, thus giving you a ton of fuel under all conditions when your car is running off VE, not just when your LTFTs push the mixture richer.
1) Richen your MAF determined fuel mixture, negating some of the effects of a lid.
2) Act the same as adding 10 percent to your VE table, thus giving you a ton of fuel under all conditions when your car is running off VE, not just when your LTFTs push the mixture richer.
most of mine are under +4. Good job on the ltrims.
09-14-2004, 11:29 PM
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this is a stock VE and IFR table. ive yet to play with it. im just showing that even w/ positive Ltrims im getting 0 at WOT which is why everyone negates the Ltrims.
Dave
Dave
09-14-2004, 11:33 PM
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Ken or Keith mentioned the other day that a well tuned computer is +-4 on the trims and the PCM doesnt do anything for fueling within those ranges. That is prolly why you see them locking at 0 for WOT
09-14-2004, 11:40 PM
#7
My guess ....Airflow/Idle learn component of the PCM. There is a whole lot going on in the background in the "learn" sector.
I spent a month, off and on, playing with my IAC Park and RAF values....result = much frustration. At certain IAC/RAF value combinations, after a "learn" period, my usual AFR plunge into the high 12s ceased!!! I had tried many solutions to this low kPa, 3000 RPM drop to no avail. Screwing with the IAC/RAF leaned it out into the 13s.
Gojo was right when he said IAC and RAF have an input/effect on overall performance/driveability. For a 512 kb file it sure is smart!! FWIW.
I'm fly by wire - there seems to be a difference in fbod and C5 Idle/Limiter tables.
I spent a month, off and on, playing with my IAC Park and RAF values....result = much frustration. At certain IAC/RAF value combinations, after a "learn" period, my usual AFR plunge into the high 12s ceased!!! I had tried many solutions to this low kPa, 3000 RPM drop to no avail. Screwing with the IAC/RAF leaned it out into the 13s.
Gojo was right when he said IAC and RAF have an input/effect on overall performance/driveability. For a 512 kb file it sure is smart!! FWIW.
I'm fly by wire - there seems to be a difference in fbod and C5 Idle/Limiter tables.
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09-15-2004, 09:40 PM
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Originally Posted by HumpinSS
Yes just unplug your maf and tune your ve table based on the trim histogram in HPTuners ONLY IF YOU ARE A STICK CAR..... Autos need not apply
09-15-2004, 10:48 PM
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We are haivng problems getting the fuel trims negative with the maf plugged in, as soon as we unplug it and adjust the ve table everything falls in line
There are numerous posts by me and Another_user about the issue here and on the HPTuners forum
There are numerous posts by me and Another_user about the issue here and on the HPTuners forum
09-16-2004, 09:19 PM
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well disregard, im finally getting positive Ltrims. So I tried to scale the VE both primary and secondary by 106% and it didnt make any difference. If you have positive Ltrims shouldnt you increase VE?
Thanks
dave
Thanks
dave
