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Old 04-13-2009, 10:46 PM   #7
Scooby Guru
Member#: 71092
Join Date: Sep 2004
Chapter/Region: MWSOC
Location: Delaware County, Ohio
2005 2.5RS Wagon
Regal Blue Pearl


You have negative values in two different areas.

First is under the "AF Learning #1" heading. Negative values there just mean the the ECU is having to revise its estimation of how much air is entering the engine downwards to match reality. For instance, you have an AFL#1A value of -1.70. If the ECU initially estimated that there was 10g/sec of air entering the engine, in reality there was only 8.30g/sec of air, so the ECU is correcting it's estimate by -1.70% to match reality. No big deal. If you're tuning, you want those all to be as small as possible, absolutely less than 5%, less than 3% if you can manage it, and AFL#1D pretty much needs to be 0.

Second is the Fine Learning Knock Correction table. This just means that the ECU has had to pull a little timing in those areas in the past and it's remembering it for the future. The values in your table aren't huge on their own. Frankly, on an NA car, if I saw -1.75 as the worst thing in the FLKC table, I'd probably be too lazy to fix it. However, those numbers work together with the IAM. Think of IAM as the chainsaw while FLKC is the scalpel. You have an IAM of .7188. Basically, that means that the ECU has pulled your timing advance down to 72% of your maximum timing right off the bat, then pulled another bit out of it where you see negative values in the FLKC table. Personally, I don't consider an engine with an IAM that low and negative learning to be acceptably safe. Subaru obviously disagrees. In fact, I've seen a number of NAs worse off than this. However, consider that Subaru wants you to make maximum power/efficiency until you're out of warranty. I want my engine to make maximum power and efficiency for 500,000 miles. There's a bit of a difference in safety factor to achieve those two goals.
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