Adjusting Ltrims... What table in LS1 Edit?
Thread Starter
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Adjusting Ltrims... What table in LS1 Edit? I've been trying to tune out an idle issue lately and in the process I've been ataping my Ltrims a lot. I've noticed an adverage at cruise rpms of +10% or so on both banks. What do I tune to get that down where it should be? I assume I want to multiply whatever table it is by about 112-114%? That should get me around -2 to -4% correct?
If it means anything, my Strims are usually right around 0%, favoring as low as -3 and as high as +3.
I won't make any changes just yet till I dial in the VE changes I'm making, but I'd just like to know in advance what table I need to mess with for Ltrims.
Thanks.
If it means anything, my Strims are usually right around 0%, favoring as low as -3 and as high as +3.
I won't make any changes just yet till I dial in the VE changes I'm making, but I'd just like to know in advance what table I need to mess with for Ltrims.
Thanks.
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Re: Adjusting Ltrims... What table in LS1 Edit? Eng Cal->Fuel->IFR
You want to add fuel in order to bring LTRIMS down (Negative). To do this scale the IFR table by ,say, 95% - whole table 0-80 kPa. Smaller number/value and PCM thinks smaller injector....so it increases injector pulsewidth = more fuel. More fuel and the O2 sensors flip rich and then PCM adjusts LTRIMS TO PULL fuel (reduce). This results in Negative Ltrims or reduced LTRIMS if you haven't reduced the IFR enough.So try 95% and drive around awhile . See where they end up.Hope this helps some.
joel(Bink)
You want to add fuel in order to bring LTRIMS down (Negative). To do this scale the IFR table by ,say, 95% - whole table 0-80 kPa. Smaller number/value and PCM thinks smaller injector....so it increases injector pulsewidth = more fuel. More fuel and the O2 sensors flip rich and then PCM adjusts LTRIMS TO PULL fuel (reduce). This results in Negative Ltrims or reduced LTRIMS if you haven't reduced the IFR enough.So try 95% and drive around awhile . See where they end up.Hope this helps some.
joel(Bink)
Thread Starter
Joined: Nov 2001
Posts: 34,663
Likes: 2,596
From: Schiller Park, ILL Member: #317
Re: Adjusting Ltrims... What table in LS1 Edit?
Eng Cal->Fuel->IFR
You want to add fuel in order to bring LTRIMS down (Negative). To do this scale the IFR table by ,say, 95% - whole table 0-80 kPa. Smaller number/value and PCM thinks smaller injector....so it increases injector pulsewidth = more fuel. More fuel and the O2 sensors flip rich and then PCM adjusts LTRIMS TO PULL fuel (reduce). This results in Negative Ltrims or reduced LTRIMS if you haven't reduced the IFR enough.So try 95% and drive around awhile . See where they end up.Hope this helps some.
joel(Bink)
You want to add fuel in order to bring LTRIMS down (Negative). To do this scale the IFR table by ,say, 95% - whole table 0-80 kPa. Smaller number/value and PCM thinks smaller injector....so it increases injector pulsewidth = more fuel. More fuel and the O2 sensors flip rich and then PCM adjusts LTRIMS TO PULL fuel (reduce). This results in Negative Ltrims or reduced LTRIMS if you haven't reduced the IFR enough.So try 95% and drive around awhile . See where they end up.Hope this helps some.
joel(Bink)
Once I feel that my idle issues are as good as possibile I'll start the Ltrim tuning process. One question though, is the IFR table the only place to tune the Ltrims? I ask because I thought I had it in the back of my head once that there was some MAF table that would also effect this value?? Maybe I'm thinking of something else though.
Just think, it's only been what,... 15 months that I've had Edit and 18 months since the cam went in and just now I'm finally getting around to these issues. What can I say, I must be a lazy b*$tard!
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Re: Adjusting Ltrims... What table in LS1 Edit? MAF table can be used to tune LTRMS. Current consensus is to use IFR if your MAF is stock. In fact many say to junk ported MAFs and return to stock MAF because of ease of IFR- LTRM tuning. MAF is left of IFR on the fuel tab.
I think it's great that you've been comfortable with your cam for the past 18 months!!
joel(Bink)
I think it's great that you've been comfortable with your cam for the past 18 months!!
joel(Bink)
