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Datalogs and knock indications

2004 Views 17 Replies 5 Participants Last post by  kris142b
I took some logs (below, please have a look) and posted them online to do a checkup on my 02 wrx ej205 and low and behold it appears that I'm getting slightly agressive knock. Looking at the logs, knocking seems to kick in around 2 lb of boost at WOT. If I'm slowly rolling on the throttle I dont pick up any knock feedback, but I have not tested this past 5psi because I dont feel like spinning a bearing. I have not seen any knock indications while at idle or normal point A to point B driving. Is there anyway anyone can help determine the source and get rid of my issues before I have a hefty bill on my hands and a lifeless vehicle in my garage. I got this car because I want to learn about cars so with that said I'm not the most mechanically inclined person. Anyway, I cant find an exhaust leak. Next step is intake tract but I have not found anything yet. I did notice my stock turbo inlet is pretty flimsy and I wouldn't doubt if it has a break in the material on the underside where I cant see. I may take the intake apart tomorrow to inspect all the pieces. Is there anything else I should try? Will cleaning my MAF do anything? Do the logs tell you something else?

Edit: Is it possible that an off brand drop in filter could be causing these problems?Other forums suggest that K&N filters cause problems.

Catless uppipe
Catless turboback
Accessport Stage II 91oct Normal wastegate
FRAM drop in filter

2nd WOT

3rd WOT
4th WOT

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They all show as unavailable for me to view but what's your knock numbers look like? Are you going wot in a high gear from low rpms? Like 50/60 mph in 5th while starting around 2k rpms for example?

Here's some reading for you.
They all show as unavailable for me to view but what's your knock numbers look like? Are you going wot in a high gear from low rpms? Like 50/60 mph in 5th while starting around 2k rpms for example?

Here's some reading for you.
Thanks for the reply. Weird, they should be loading fine.

I started every log from 2000rpm and ended wherever after 5k.

I have a Feedback knock of 0 across the board in all logs, but around 2800 I seem to get a high Fine knock learn of 2.81 and other numbers across the board with 2.81 being highest in all logs.

EDIT: Figured out why links werent working. They should be fine to view now.
From what I see, it looks as though you're lugging the engine, which is extremely bad for it. But I'm still learning this stuff, so someone else who is more knowledgeable can confirm what I think or tell me if I'm wrong.
I drove around to see if anything was unusual, it sounds like the turbo is exposed somewhere. It's louder and more raw sounding than before. So I know I have a leak I just don't know where. My exhaust seems intact I can't find any leaks.
Your car is pulling global timing. Your DAM is down 1 point (general octane correction) and you have learned timing at decently high load.

Ensure that you have used quality gas, 93 octane, and check for boost leaks. Something is going on, likely mechanical.
I cleaned my MAF as suggested by a few, reset my ecu and went for a drive. AF Correction is now anywhere between -25 and +25, and my AF learning 1 is at a constant +7.xx. I noticed when driving low RPM in vacuum I hear turbo whistle quite loudly when driving alongside anything. If I start getting into boost I hear a clear decently loud sucking sound that you'd get with aftermarket intake that I never had before. This sounds to my noob ears to be an obvious intake leak but I cant find anything. My only guess is stock turbo inlet as it looks like a piece of dog turd. The end coupling is flimsy and soft and looks like the hoseclamp may be eating it away. I cant get my hands under it to feel around and I cant hear anything under the hood at idle or when revving under the hood. I'm so lost.:unhappy:

As for gas, I try to pick decent places. We dont have a lot of options where I live as I'm in a small town and 99% of my driving is within the county. I fill up at BP or mobil which seem to be the best options. We also only have 91 around here unless I drive 50 miles then there is a station or two which offer 93.
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Get a vacuum leak test done, most places will check for a boost leak at the same time.

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I called around to see if anyone in my area would do it, all basically told me they dont do vacuum/boost leak test on subaru because they dont have the proper coupler I guess?
I find that hard to believe. Check local performance shops.

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Do a boost leak test, you have a leak somewhere. You can make the tester yourself for $5 - $10.
Yeah it isn't hard. I don't know about the bugeyes but mine had a leak at the intercooler and turbo connection and the intercooler throttle body boot had a small one. Was a simple fix.

I would start there though. If the engine is getting the wrong amount of air the fuel will be way off and you will have issues.

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Alright after cigar smoke test and trying my vacuum boost tester I made I think I found the problem. A hose connecting to the throttle body from the inlet was disconnected from the throttle body. Got it put back on, checked everything else, reassembled and ran my vacuum test again with no more leaks. Went out for a drive and hit target boost. It also idles smoother now as well. I did get one knock reading of -2.11 so I guess I got that to figure out. I did a fresh ECU reset so I'm hoping it's just because it hasnt been really learning anything yet.
Some knock is completely normal, particularly if you see only FBKC at low loads (< 1.5).

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I forgot to restart my car after ECU reflash so that explains the knock numbers. I drove the car later after the ECU was actually truly reset and it was fine. Didn't get a single knock so far. AF learning and correction have both normalized down to near 0 numbers. DAM went from 12-14 with normal driving then I did a few pulls and it immediately shot up to 16.
Yep. Initial DAM is 12 for stock maps.

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Problems never end. It was fine for about 2 days, did a 100 mile trip out of town and problems started again. Was missing target boost by 2-3psi, got fkl and feedback of -2.xx followed by -3.xx then even shot up to -6.xx. Driving to my location my AF learning was around 5 at cruise. After being off for a few hours at location and then idling before heading back home my AF Learning 1 was -7.xx. Took it easy home and noticed on the highway that in 5th at cruise, if I let of the throttle by the slightest amount I got a knock feedback of -3.xx and it held until I either eased up more or applied more throttle. I datalogged it and I will post in this. Figured I missed a leak or something, performed my leak test again with no leaks anywhere other than from open oil filler cap. I replaced it and tested at lower pressure to be sure and no noise or bubbles came from anywhere. I did notice when putting everything back together that my buddy didnt get the top of the airbox seated properly and it hanging off the bottom by an inch or two which explains the aftermarket intake sound I heard before but still... thats pre maf and doesnt explain the high knock reading. When I fixed the hose that was disconnected and reset the ECU it was an unusually cold day (42*F) and I performed the fix at night (even colder), the days following were pretty warm (upper 60s). I'm wondering if that had anything to do with the weird knock and stuff since the ECU only learned in the cold and suddenly it was hot out?

As a side note, the hose which was disconnected was the Inlet to PCV valve hose. I'm wondering if the valve is possibly bad since its been open to the elements for who knows how long? I may replace that and see what happens.

5th cruise knock...
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New MAF in, getting 200+ g/s at WOT and hitting target again. Reset ECU (rolls eyes) for the millionth time, and did a hard reset. Still got some random -2.11 through 0 fkl and feedback always at a low cruise or just doing granny driving through town. Still getting constant 0 - (-1.41) FKL when easing off throttle at low cruise I also noticed I started getting +0.3x and +0.7x FKL, assuming my MAF fixed the issue at some points and its adding timing back?

Good news, it felt like it was a lot smoother normal driving at bottom end of gears and even at idle. Wasnt super jumpy and now I can tell it was hesitent before with the difference. Also, I started her up in my garage and heard/found a rattle. I could never get the invidia catless DP to line up with the mounting bracket coming off of the transmission and I guess its making a rattle against the bracket which is what I'm hoping is the final cause of all my knock feedback and learn seeing as it is usually at low rpm.
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