Idle LTRIM question
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Idle LTRIM question At idle (900rpm, stock motor with cam) I'm seeing around 1.5g/sec on the MAF reading, along with +15ltrims. In the left most spot on maf airflow vs. frequency table (cooresponding to frequency 1500), I have 2.46g/sec.
I'm a bit confused as to how to proceed.
Thanks,
Terry
I'm a bit confused as to how to proceed.
Thanks,
Terry
Originally Posted by Terry Burger
At idle (900rpm, stock motor with cam) I'm seeing around 1.5g/sec on the MAF reading, along with +15ltrims. In the left most spot on maf airflow vs. frequency table (cooresponding to frequency 1500), I have 2.46g/sec.
I'm a bit confused as to how to proceed.
Thanks,
Terry
I'm a bit confused as to how to proceed.
Thanks,
Terry
The airflow at idle pretty much ignores the MAF and
uses the speed density airflow calculation. This result
points to an over-lean VE table most likely, though
other mixture affecting mods might be in play (?).
uses the speed density airflow calculation. This result
points to an over-lean VE table most likely, though
other mixture affecting mods might be in play (?).
Secondary is for MAF faults, and if you try to tune SD
by taking the MAF out this is the table you have to work
with (and then back-propagate the changes to the Primary
table & fill in the blanks, if you want to go back to normal
operation).
by taking the MAF out this is the table you have to work
with (and then back-propagate the changes to the Primary
table & fill in the blanks, if you want to go back to normal
operation).
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I fixed it by playing with the maf scaling table. Appearantly I was making some sort of unit of measure error! When I multiplied my maf scaling by 1.10 the ltrims went from +12 everywhere to +4 everywhere. I'll play with it more later to dial it in.
Thanks,
Terry
Thanks,
Terry
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The airflow PID (from what I have seen) is always replaced with what the MAF reads. Even at idle when the PCM relies on VE/SD. I know this because at idle with the MAF plugged in my airflow would be about 5-6 g/sec. With the MAF unplugged it is about 10 g/sec. Any changes like a lid change what the MAF reads, especially at low RPM. You need to unplug the MAF, tune VE until everything is about zero, plug the MAF back in, and scale the MAF table (probably about 10% richer) until it is close again. Until somebody does a proper flow of an intake with a lid that is all you can do.
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As far as I know the MAF table is the only way to adjust fuel ratio, aside from minor tweaks in the VE table (which generally contribute only a small amount to fuel ratio). Let me know if I'm wrong!
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Originally Posted by stangkillin99ss
how is it possible to tune the Ve table with the MAF unplugged when the PCM reads secondary Ve for that situation and Main Ve for situtaions with the MAF plugged in?
I always update my primary VE table with the data I get from my secondary, even if I don't use it. Just picky I guess.
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A month from now, don't say I didn't warn you. Check out the details on my (yet to be approved last time I looked) tune I posted on Horist's website. This thing has not been sitting in a box at my house...in fact my wife is starting to rather dislike HPTuners.
I already made the mistake of trying to tune with that blasted MAF plugged in...but I got my revenge. It is now sitting on a shelf in my garage collecting dust.
I already made the mistake of trying to tune with that blasted MAF plugged in...but I got my revenge. It is now sitting on a shelf in my garage collecting dust.
Originally Posted by Another_User
A month from now, don't say I didn't warn you. Check out the details on my (yet to be approved last time I looked) tune I posted on Horist's website. This thing has not been sitting in a box at my house...in fact my wife is starting to rather dislike HPTuners.
I already made the mistake of trying to tune with that blasted MAF plugged in...but I got my revenge. It is now sitting on a shelf in my garage collecting dust.
I already made the mistake of trying to tune with that blasted MAF plugged in...but I got my revenge. It is now sitting on a shelf in my garage collecting dust.
I have alot of note books full of information I've collected/tried in the last few years.There is no reason to get rid of the MAF or tune open loop if you run a Cam under 245/250 on a 346. All the smaller Cams can be tuned with all the sensors still hooked up and have excellent idle/low speed driving that doesn't change on you.Just takes alittle time to figure out what works for your setup
I almost never touch the MAF table unless it is ported or a different MAF is being used.
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Slowhawk -with all due respect, does the 245/250 closed loop statement apply if it's on a 106 LSA?? I'm running a 239/251, 106 - Open Loop, on the MAF ( I like my MAF 
). I've rescaled my MAF at the lower values in order to get it to idle at about 15:1 AFR (FJO WideBand). Every other option I've tried to pull down the AFR hasn't worked very well. If I pull the AFR down a little more ( so LTrims will go negative) can I run it Closed Loop?? What do you think?? Thanks in advance!
). I've rescaled my MAF at the lower values in order to get it to idle at about 15:1 AFR (FJO WideBand). Every other option I've tried to pull down the AFR hasn't worked very well. If I pull the AFR down a little more ( so LTrims will go negative) can I run it Closed Loop?? What do you think?? Thanks in advance! 
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Originally Posted by Terry Burger
As far as I know the MAF table is the only way to adjust fuel ratio, aside from minor tweaks in the VE table (which generally contribute only a small amount to fuel ratio). Let me know if I'm wrong!
IFR
F/A Multiplier Table(stoich)
VE Table
MAF Table
PE Table
Air Adjustments:
Idle AirFlow Parked (IAC)
Idle AirFlow (Running AirFlow)
Throttle Follower AirFlow
Air Adjustments do effect overall AFR.
FWIW.