Knock Retard Jumps to 8 under Light Load

[Meswan]

Hi, first ever post here. I have a 2011 Speed3 with an engine or something near it that makes the knock sensor go apeshit around 1750-2500RPM and light load (the problem actually seems to get better the more gas I give it; WOT is normal but I don't like getting on it too much because of my tune, or lack thereof). I have been unable to get my car properly tuned because of this. I've tried searching for this issue countless times but have yet to find what's causing it. Yes, I've read the Stratified article... more than once.

The problem started a couple months after I went on a whole VVT/timing/injectors and seals/catch can install endeavor. Some days it's milder, some days it immediately jumps to 8 whenever I pass 2000RPM. If I get off the gas and back on outside of the "problem range" it doesn't come back. It seems to do it more when I start light on the gas and lean into it slightly. It only starts happening once the car has been fully warmed up (180°+) for several minutes, getting progressively worse until it's as bad as it's gonna be. The engine doesn't sound any different than the last one that was in it and I didn't notice this problem with that motor. I would think that a noise loud enough to max out the retard would also be noticeable to my ears, but I may be wrong.

Here's what I know HASN'T fixed it:

• Injector seals (installed new CS seals and injector studs during timing endeavor, reverified torque months later)
  
• HPFP service
• New knock sensor
• New fuel pressure sensor
• Walnut blasted intake valves
• Re-insulating the catch can to prevent metal-on-metal knocking noise travelling through the PCV
• New VVT oil control valve and cleaned filter (I couldn't see the sun through it, I was SURE this was my issue. Power is, however, waaay better after this job)
• Exhaust downpipe-midpipe donut (was missing since I got the car, thought some noise might travel back up to the engine)

Year/Make/Model: 2011 Mazdaspeed3
Mileage: 138,000. Engine mileage unknown but I was told it may be about 20,000 less than the body.
Location: Florida
Concern: see above
DTC's: Secondary O2 sensor dead, EGR delete causing EGR code, random cylinder misfire on cold start. No other DTCs on AP.
Modifications:

• Autotech HPFP
• Cobb SF intake
• eBay TIP
• BNR S3
• Corksport EBCS
• CX FMIC and piping
• Turbosmart 50/50 BPV
• NGK 1 step colder plugs
• Damond PCV plate
• Damond EGR delete
• DIY vented catch can routed through PCV valve to manifold inlet with the appropriate check valves (Catch can --> manifold, catch can --> vent)
• Unknown catless downpipe
• Muffler delete
• Damond TMM and RMM, street duro

ECU/Tuning Software: Cobb Accessport V3
Tuner: OTS stage 3 (yes I know... this is why I'm posting here)
Is the concern intermittent? Can you duplicate the concern? Very consistent issue. It makes me want to drive the car off a bridge.
Recent Repairs: see "what hasn't fixed it". Written roughly in the order they were done in, over the course of 2 years

At this point the only things I can think of are a failing flywheel (stock) or internal bearings with way too much clearance. I don't hear any rod knock whatsoever, but I can't exactly say I trust this engine to be in perfect condition inside.

I'll include a couple datalogs. The first one is cruising through a neighborhood right where this thing likes to give me issues, and the second is speeding up at a moderate pace to about 50mph. If the logs suck let me know what you want me to do and I'll record a new one.

 

[Enki]

Couple things
1. Don't run step colder just cause; do it because your tuner tells you to or you know you need it. Doubt you do on an S3.
2. The KR looks resonant to me; seems that it always happens in the same RPM range regardless of timing, and might be lessening as the engine warms up.
3. Add accel pedal position and coolant temp to your logs; not sure why you don't log everything when you have an AP though.

 

[Meswan]

Couple things
1. Don't run step colder just cause; do it because your tuner tells you to or you know you need it. Doubt you do on an S3.
2. The KR looks resonant to me; seems that it always happens in the same RPM range regardless of timing, and might be lessening as the engine warms up.
3. Add accel pedal position and coolant temp to your logs; not sure why you don't log everything when you have an AP though.

1. I've seen that said here more and more over the years. When I bought them I figured they wouldn't really hurt anything and be more of a "future proof" mod but they are getting a little old and I just found out stock plugs are dirt cheap on Rock Auto so I have a set on the way now. I am going to make sure they're gapped right before they go in.
2. Yeah it does look resonant, I'm just not sure what might be resonating at this point. I feel like I've been through the whole engine bay more than once and secured anything loose or in risk of hitting other parts. It actually gets worse the warmer the engine is, when the water temp first gets to 180 it'll usually behave fine, maybe starting to act up. It's when it sits at max temp for more than a few minutes that it gets really bad.
3. My bad, I didn't even think to check what I was logging before I started. Been a hot minute since I recorded one. I've attached a few more logs, 22 is coming up to full temp, 23 is at full temp and problem "creeping in", 25 and 26 are catching the KR spike while driving in faster and slower conditions.
Thanks for taking the time to try to help! This problem has been plaguing me forever