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Old 10-01-2013, 10:03 PM   #1
wchafe
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2014 STi 5dr
WRB

Default Feedback Knock - 2013 STi Cobb Stage 2 91 v 332

I'm posting this log through google docs. This is the first time so I hope you can see it!

https://docs.google.com/file/d/0Bzn7...it?usp=sharing

This is a 2013 STi hatchback with Cobb Turbo-back exhaust and Cobb Stage 2 OTS 91 Octane v332 map.

Would someone please have a look at this log and comment on the knock events? The log is about 10 minutes of driving around, city and highway. The events I'm concerned about are at lines 678 and 970. At one point, I think the first event, the car dropped from S# mode to flashing [s], and the Check Engine and Traction control lights lit up and stayed on. I had to reset the codes which were misfire on Cyl 3 & 4.

The night before I had done a pull from 2000 to 6800 in fourth gear right after flashing with the v332 map without any sign of feedback knock or fine knock learning.

Thanks,
Wade
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Last edited by wchafe; 10-01-2013 at 10:17 PM.
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Old 10-02-2013, 12:58 AM   #2
Domain
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You sure this is the correct file? This was for city and highway driving?

You triggered a CEL (maybe line 425... shift -> overboost?) and then continued push the car at high RPM + WOT?
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Old 10-02-2013, 12:22 PM   #3
wchafe
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I ran into a problem with google docs only showing 1000 lines so I trimmed it down to just the highway part. Boost target is 18 +/- 1psi so there's no overboost. I didn't push it after the engine light came on but I'm not sure where in the log that happened. I think it was at one of the points I mentioned. At that point it had dropped out of S# so max boost would have been limited to 15.5 anyway.

COBB Tuning, v3.32 -- Stage2 91 v332 Boost Select - Intended for 2013 Subaru Impreza WRX STi vehicles with stock intake system and a turbo-back exhaust system with high-flow catalytic converter running 91 or 92 octane petrol. Boost Targets: ~18psi (S#), ~15.5psi (S) or ~8psi (I) peak boost pressure, +/- 1.0psi.

Last edited by wchafe; 10-02-2013 at 12:58 PM.
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Old 10-02-2013, 12:53 PM   #4
Cobb Tuning
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How many miles do you have on the car? Do you have any other engine modifications? How about an aftermarket clutch, flywheel, or lightweight crank pulley? What altitude do you live at? If you don't know, just google it and you can easily find out.

Given the consistency of those timing corrections and the fact that you are throwing misfire CELs, something is definitely off. Your fuel trims look good, so a leak is unlikely. It's never a bad idea to get a pressure/smoke test though to verify that everything is sealed up correctly. Given that the car is a 2013, it's unlikely that the spark plugs are worn, but you could pull the plugs and see how they look and double check the gap on them.

Let us know the answers to the questions above and we can go from there.

Chris
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Old 10-02-2013, 01:03 PM   #5
wchafe
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Thanks for taking a look at this!

Mileage is about 7000 miles. Altitude is in the range of sea level to ~500ft. OAT was about 15°C. I live in St. John's, NL, Canada. No modifications other than the Cobb downpipe and catback. All else is stock.

Last edited by wchafe; 10-02-2013 at 01:10 PM.
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Old 10-02-2013, 06:12 PM   #6
Domain
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I'll let the experts chime in, but these are the lines I referred to earlier...

Code:
Time	FK	FKL	AFR	Boost   TDBE    RPM	TPos	WGDC

208.056	-1.4	0	11.48	18.3	-2.49	4866	100	26.27
208.389	0	-1.4	11.03	17.91	-2.04	4927	100	20.78
208.727	0	-1.4	11.03	17.72	-1.86	4924	100	16.08
TD Boost Error is -2.49... this section (along with the lines before/after) looks really strange because it shows you are WOT for 3-4 seconds, but you aren't seeing any movement RPM wise.
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Old 10-02-2013, 06:29 PM   #7
wchafe
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WRB

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I was shifting so I think what you're seeing is an artifact of the Cobb "Flat Foot Shifting" function. I sometimes still clutch out of habit even when FF is enabled . I think I did that briefly then got back on the throttle before letting the clutch back out. The FF function is set to hold the RPM at 5000 and keep boost up until the clutch is fully re-engaged. Thus you would see 100% throttle and RPM steady at 5000. Good eyes noticing that! Thanks for your input, I appreciate it.

WRT the knock, my understanding from reading the forums is that erroneous knock like you see here is common during shifting so I didn't think the knock indication at this point was an issue. Of course I don't really know, I'm a noob, so please correct me if I'm wrong . Definitely a lot going on there, with my clutch stumble, FF Shifting kicking in, big boost swing, and wastegate changes.

Last edited by wchafe; 10-02-2013 at 06:36 PM.
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Old 10-07-2013, 05:00 PM   #8
sebi1990
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why the log sooooooo long?
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