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Discussion Starter · #1 ·
So my DAM been dropping and feedback knock and fine knock learning for the 3 days after my service at the Subaru dealership (there's a picture of the service below). Can anyone tell me what's going on with my car? Btw, I have Cobb j pipe and Cobb big SF intake with OTS map stage 2+ 91. Here's the picture below. But my DAM goes up to 1 after highway run.
 

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Well on the earlier cars, before the DIT on the 2015+ wrx's, any drop in the DAM is a sign that something could actually be going wrong. However, on the DIT cars, such as your wrx, a slight drop in the DAM shouldn't be as surprising or alarming as before with non DIT vehicles. Determining whether there is a potential issue on a DIT vehicle require considering how low the DAM has dropped and what the Knock Feedback Correction and Fine Knock Learning look like. Most of the time these events can be summed to false knock, or knock created by poor gas. Anything with a -2.5 degree or less is actually considered to be normal. Now if there is any knock during a WOT pull or while in boost, it could be more of a sign of a issue with the engine.

As if right now I would not be too alarmed. Do a WOT pull in 4th gear from 2500rpms to redline. If you see any knock, or your DAM drops at all immediately stop and stay out of boost, as there could actually be a problem.

My first assumption would be fuel quality. Take the fuel down until the fuel light comes on and be sure to fill up at a reputable gas station such as Sunoco, Shell, or exxon. Stay away from gas at places such as Sheetz, Loves, or places like that. As they tend to have poor fuel compared to stations that main focus is on the fuel they sell.
 

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42 Posts
Discussion Starter · #3 ·
Well on the earlier cars, before the DIT on the 2015+ wrx's, any drop in the DAM is a sign that something could actually be going wrong. However, on the DIT cars, such as your wrx, a slight drop in the DAM shouldn't be as surprising or alarming as before with non DIT vehicles. Determining whether there is a potential issue on a DIT vehicle require considering how low the DAM has dropped and what the Knock Feedback Correction and Fine Knock Learning look like. Most of the time these events can be summed to false knock, or knock created by poor gas. Anything with a -2.5 degree or less is actually considered to be normal. Now if there is any knock during a WOT pull or while in boost, it could be more of a sign of a issue with the engine.

As if right now I would not be too alarmed. Do a WOT pull in 4th gear from 2500rpms to redline. If you see any knock, or your DAM drops at all immediately stop and stay out of boost, as there could actually be a problem.

My first assumption would be fuel quality. Take the fuel down until the fuel light comes on and be sure to fill up at a reputable gas station such as Sunoco, Shell, or exxon. Stay away from gas at places such as Sheetz, Loves, or places like that. As they tend to have poor fuel compared to stations that main focus is on the fuel they sell.
My DAM only drops when I'm in 4th and shifting to 5th around 3000-3500 rpm. It's drops to .812 and will go back up to 1 after cruising about 10 miles. Thank you for the info tho. It helps a lot
 
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