Fine Knock Issue

[inelement207]

Any thoughts I can reproduce this consistently 2010 WRX drving in third gear 3700 to 4400 RPMS light throttle (20%) light load partial grade or more holds -1.4 until i let off or get into it

Full throttle third gear pulls no issue with knock except mashing throttle occasionally will do it under 3000 RPMS

https://docs.google.com/a/maine.edu/spreadsheets/d/1obV_UxHSaMs-0S0ycDa0OLiTLqkV1Wmt4xPGvXK37ow/edit?usp=sharing

 

[drvsdwz]

Fine knock is ok, it is learned so it is pulling timing by 1.4 degrees for that load and rpm. If you're getting feedback knock of more than 3 at any given time, that is when I would start worrying.

It could be a bad batch of fuel, maybe even a dirty air filter.

Reset the ecu and see if it relearns it

 

[inelement207]

Rarely feedback knock. This is always reproducible Cobb intake clean and oiled. Etc reset periodically no change. Maybe I'll wait till summer blend hits. Thanks for the advice. I have accesstuner but really was not thinking it was good thing to try and tune out. Seems like ecu is doing as it should.

 

[drvsdwz]

did you clean your maf sensor after you oiled the filter? personally i like dry filters because you don't have to worry about contaminating the sensor

 

[inelement207]

Oiled it outside the car, this was reproducible on stock airbox as well, may try maf clean next time I'm in there for the hell of it

 

[RyanR]

If you're getting fine knock for more than 1 or 2 tanks of gas, especially in the same load range, you need to tune it out.  -1.4 isn't much to worry about- but I wouldn't run it that way forever.  You could also check all of the bolts around the knock sensor/on top of the block/intake manifold.  Sometimes all it takes is one of those loosening up.  Can also be a nut someone dropped on top of the block.

What PSI is this happening at?  If it is less than 5-7psi, you could need some fine tuning of your OL/CL transition.

 

[inelement207]

working through it bit by bit, as temps have warmed still have same spot load/throttle/RPM wise but fine knock learn has dropped to 0.3. Currently chasing some small vacuum leaks, and some oil coating the intake form overfilling slightly. Once that's all set I will inspect the filter oil if necessary, run for a bit then clean the MAF.

this occurs as soon as you touch the throttle a bit before the transition form open to closed

I am using a cobb off the shelf tune, DP will go on next week , and will head down to granite state for a pro tune

Ill update as I find things, recently replaced all the PCV parts and my a/f learning C went from + 6-7 to - 2

 

[inelement207]

and shes done of to kinetic

 

[Hiker39]

My 2008 Outback knocks on regular unleaded only if I drive in regular automatic mode

. in sport or if I drive aggressively... Nothing.