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Old 01-27-2013, 01:26 PM   #4
Cobb Tuning
Member#: 4803
Join Date: Mar 2001
Location: Austin, TX

Originally Posted by Tenormdnes View Post
AF Learning 1
A: .6 .6/.6
B: -.8 -.8/-.8
C: -1.5 -1.5/-1.5
D: -.2 -.2/-.2

So what the heck does this mean? I was at idle when I pulled these numbers. This car is new!! Thanks for the help Bill!
Your A/F Learning 1 numbers are fine.

The DAM dropping to zero is a serious problem. There could be many different causes. For example:

1. Low octane gas (such as 87 octane) was put into the car. This could be deliberate (say someone else driving your car and doesn't know) or the gas station mixed up different octane gas in the pumps. The latter isn't very likely, but I would go ahead and fill up at a different station with premium gas.

2. Something rattling in the engine bay (such as a loose heatshield or other component that is attached to motor or tranny) that the knock sensor is picking up and erroneously determining that knock has occurred. You might not be able to hear it from inside the car when driving. If you know of anything that has been touched/repaired/replaced double check those items to make sure nothing is potentially loose. If you hear a rattling or other unusual noise, try to isolate what that is.

3. Severe knock caused by a severe mechanical issue. This could be anything that would induce severe knock such as fueling problems.

4. Damaged ringland - unfortunately, some Subaru motors develop this problem, whether they are bone stock with factory tune or modified. This results in the a lot of noise in the offending cylinder which the knock sensor determines as excessive knocking.

At this point, I would fill up with the different gas and then keep your eye on the DAM and see if it starts to go up. Drive conservatively. Also, add the 4 Knock Sum parameters to your log list (via "Monitors" -> "Set Data Log List") and get a long log of just general driving. Don't be concerned about the knock sum values themselves - they are meaningless, but we want to see when they increment and if it is isolated to a particular cylinder. Post the log up at (select "Go Advanced" and "Manage Attachments" to attach the log). Goggle docs does not work well for large logs.

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