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Feedback knock runs my life

12398 Views 6 Replies 2 Participants Last post by  zax
Hi everyone! Well first let's name the car. 2014 wrx, COBB sf CAI. Accessport, and a Invidia 3" straight pipe, and a couple of stickers (extra HP) now on to my problem (why do WRX's always have problems?) drove up the canyon today on some dirt roads (because I won a rally car) got back on the road and hear loud clanging noises from underneath the car. I assumed it was just rocks making their way out of the car from being kicked up by the tires. Then I heard a unpleasant sound, like every bit and bolt under my hood had fallen off and onto the road. I still assumed it was just rocks but didn't sound right now me. So I kept driving ironically.

I'm just about home and I'm behind this very Slow old ford truck and he's doing 35 in a 55 so I get over and stomp the gas in third. All the sudden Feedback knock jumps to -11.58 and I hear a bad hissing/whistling noise under the passenger side of the hood. Kept driving till I got home. Checked for any missing bolts. Looked specifically at the DP and the turbo. Checked the oil and it was fine. Not sure what it could be unless these rocks just F***** my exhaust up and it has a huge leak now. Someone help me. Just put a brand new clutch in this baby now time to put more money into it if it's something serious. I'm also guessing it could be a loose air intake coupler maybe?

Sorry for the long write.
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I guess I should also note fine knock learn was reading still at 0 and DAM was at 1.0 AF seemed fine as well.
Probably road debris producing false knock.

There is really little value in monitoring FBKC. This and the knock count often indicate timing pulled due to causes that aren't actually engine knock. The knock sensor is an acoustic transducer and many things can trick the sensor into thinking it detects detonation.

It is more important that you keep an eye on FLKC and DAM, as these parameters tell you a lot more about repeatable knock events to which you can gain confidence are related to timing or fueling.

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Thanks for all the info I'll defiantly just monitor FKL. So on the way to work I listened to my car and it does seem to be my air intake. It whistles at around 50-55 MPH so I'm sure something is loose or it just contracted a bunch of dirt and material and needs to be cleaned
I would personally have a look at my stored fuel trims -- 55mph is generally in AF Range C, so if you have a vac leak (particularly one loud enough for you to hear) it would likely affect your fuel trims.

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I do have a vacuum leak somewhere because sometimes I see on my Boost monitor -39 at some points but it defiantly sounds like it's coming from the air intake so I'll check the couplers and see what's up with it. I had a boost leak with my intercooler coupler, only would push 12 pounds now back at my peak of 17
I do have a vacuum leak somewhere because sometimes I see on my Boost monitor -39 at some points but it defiantly sounds like it's coming from the air intake so I'll check the couplers and see what's up with it
Unfortunately this is not a confident indicator of a vacuum leak.

Monitoring your Fuel Trims will tell you much more.
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