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Discussion Starter · #1 ·
New Subaru owner here! Think I may have a problem based of what I’ve read but recently bought a ej257 swapped outback motor has cp3 rods and pistons and I have been monitoring my feed back knock today it hit -11.2 @ 2500 rpm 3 rd gear
I have seen it hit -8.4 every know and again only have monitored feedback knock the last 3 days numbers tend to stay below -2 and I only see big spikes at low rpm my fine knock learn I’ve seen hit -2.8 but that’s only when WOT please help!
 

· Not a mod... or is he? Or, is he not?
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You have an issue. I'd start with basic stuff. Plugs, coils, boost/vacuum leaks, clean the maf and get rid of any oiled filter and replace with a paper/dryflow. It could also b a tuning issue.

Have you checked anything yet? -11 is quite a bit. What does the dynamic advance multiplier look like? If you use cob it should be 1. Open source uses IAM and should be 16
 

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Discussion Starter · #3 ·
  1. I haven’t checked anything as I don’t know where to start
  2. Dam has been 1.0 and has never changed
  3. I believe it was tuned in Denver and I’m from Montana so I did have the idea of elevation being a problem
 

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Simply referencing FBKC values without also indicating where in the table these knock events occur adds little value. FBKC is applied against a table of RPM vs. Load. High load knock is concerning. knock events that occur in the same area of the table typically become FLKC or DAM decrement depending on the ECU conditions.

That said, 11 degrees of timing is a lot to pull with a single event. You should do your due diligence and log the car for the event. Remove all other parameters from the log EXCEPT RPM, FLKC, FBKC, and calculated load. Vehicle speed is also a plus. Go driving as per normal and log these parameters.

Low-load random knock is very often drivetrain noise. if the Knock events are completely random in the table and low load (during vacuum), it is also probable that you have a vacuum leak. It would be prudent to also look at your AFR Learning values across the different learning ranges (A,B,C,D).
 

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Please start a new thread as it is a completely different ask from the OP.
 
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