RomRaider

edit: after i typed this post i got thinking and checked the knock correction settings in my map and i've got fine learning enabled above .50 load, whereas the stock map has it enabled above .75 load - which would exclude most but not all of the data in my log. so i don't think it's simply a case of the knock sensors being set to be too sensitive.

i have a 2005 sti stage 2 and have been trying to figure out a weird issue. i am considering flashing back to stock to see if it goes away but i thought someone here might have an idea first.

i am getting negative feedback knock correction and fine learning knock correction while cruising around in 6th, and i've also occasionally seen it in first and second when barely accelerating - such as taking off slowly from a stop while giving it just enough gas to not stall out.

i can't post the map as it was part of the agreement i made with my tuner not to share it however i will provide as much info as possible upon request. also i've tried changed everything from 1.15 load and below back to stock (fuel/timing/etc) and it is still happening but i may have missed something.

my thoughts are maybe i have a faulty sensor or something is rattling around and causing false knock. i've checked what i can and everything appears to be fine under the hood so i'm not sure what to do about it.

i normally run ethanol-free 93 octane, but i tested with 50/50 93/110 octane race gas, same results. that's why i'm thinking it can't be real knock. how could it be knocking on stock timing/fuel under vacuum on race gas?

egt's while crusing are around 1000-1200, closed loop fueling around 14, -5 manifold pressure, etc. details are in the attached log file.


mods, etc-

sti grp n engine and trans mounts
various suspension mods (springs, sways, steering rack bushings, etc)
stock intake/filter with silencer removed
lightened crank pulley
1 step colder plugs (ngk iridium)
perrin turbo inlet
stock vf39
stock ic
3" catless tb exhaust

car is extremely well maintained and idles and runs perfectly smooth. consumes no oil and no smoke or any weirdness in the exhaust. coolant was recently flushed and was/is perfect. compression checked when plugs installed and was perfect. oil was recently changed and i run german castrol 0w30 and mobil 1 filters. no cel's or any known mechanical problems. recently dyno'd at ~300 wtq and ~290 whp.

29 views and no comments?

I was thinking about this over night and I was studying the closed loop AFR readings vs my wide band and the stock sensor appears to be ~1 point lean. So I'm going to clean the MAF really well and reflash/reset the ECU and see what happens.

I'll post up if that helps so that others can learn from my experience.

All cars seem to occasionally see knock at cruise range RPM and load. You could probably take -2 degrees out there and it would still do it. It is more prone in higher gears if RPM and engine load are otherwise the same. I've listened to the knock sensor before when it does it and I couldn't hear any knock. I tend to think the car is just extremely sensitive to knock at low loads and RPM. Just guessing, but the factory may push timing for emissions and fuel economy and counteract by using extremely sensitive settings for the knock sensor.

It would be helpful to log AVCS and total ignition timing. Are your timing and AVCS maps pretty much stock at that load/rpm?

I bet your LC-1 just needs recalibration. Take your sensor out of the exhaust, blow on it, hit the calibrate, put it back in.

Complaining about views isn't going to help you. Have a bit of patience, please.

My stock sensor and WB are about 1/2 a point apart. I think some of it though might be sample delay or the delay in seeing the exhaust since, my wideband is downstream of the stock sensor a couple feet.

I'm sorry I didn't mean to complain.


I never thought to look at AVCS timing. I'll see if anything weird is going on there.

Also good to know your wb reads slightly off as well. I will try a calibration just in case.

I was thinking it might be normal since the front o2 sensor is in the uppipe but my wb is about 6 inches down stream from the turbo but I just don't have any experience with this stuff.

I cleaned out the maf really well today so I'll check those other things and see where I'm at.

Thanks a lot guys.


Edit: AVCS timing is stock for the area in question.

I get the same thing as you in my LGT (same engine).

No FBKC at high loads, but weird stuff at low loads. I have taken up to 8 degrees out, and my learning view still populates with high negative numbers at times.

Like this:



From this thread I started a while ago:

topic3321.html

Hmmmmm very interesting.