Quote:
Originally Posted by solidONE
So there is a difference in front pipe diameter, everything else is more or less the same. Mine is 2.75"
Your IAM fluctuating is supposedly normal on pump gas. One way to make it come back up to 1, I found, is to make some easy pulls to high RPM with more than half throttle. When you do this, and the computer does not sense knock your KC Learned value goes past 5 up to 6. Each time KC goes past 5 and above the computer adds more IAM value until it's back at 1.
I'm guessing the IAM value is dictated by knock or lack thereof while under load. No knock, increase IAM. Knock? IAM gets dialed back. Any value less than 1 is due to knock retard basically. Am I right?
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that's pretty much it. iam is part of 'coarse correction'. so, it's one of three knock control strategies being employed one at a time, at any given time. when the ecu hears what it believes to be a knock event, it'll decrement fine learning in the cell you were in when it happened. if the pulled timing from that event is great enough (usually around 3 degrees) it'll drop the iam. this pulls timing blindly across the board, as total timing = base + (iam * advance) + compensations + corrections.
so the long and short of it is that iam (coarse correction) is the nuclear option. if your iam isn't 1, the engine already saw what it considers to be serious knock. also, since it's only one of three strategies with only one active at any given time, an iam of 1 doesn't mean your car isn't knocking somewhere. it's actually quite easy to disable the iam altogether and just make it always read 1, which i've found many tuners do to combat iam dropping due to insignificant tip-in knock. so, you have to look at the whole picture to know what's going on: coarse correction, fine learning, and feedback correction.