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BTSSM says I have knock


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I put in the all new MAF and woah! What a difference. Fuel trims on the LV are way better than before. I didn't get a knock warning and I haven't changed those paramaters either! My baby is pretty happy. I never thought changing the MAF would make such a dramatic difference. These things should be swapped out every few years. I took a short trip on the highway, from one entrance to the very next exit and man is my car happier. Got boost to 10.5 PSI and no issues.

Next plans are a new leakdown and compression test to compare with the original and install the new AFR.

I'll post a log and a LV later tonight.

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Glad you got somewhere with this issue. Having similar problem with a friends car.

 

Ordering a denso maf is back on my short list for my lgt when I'm able to get to work on it again

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I put in the all new MAF and woah! What a difference. Fuel trims on the LV are way better than before. I didn't get a knock warning and I haven't changed those paramaters either! My baby is pretty happy. I never thought changing the MAF would make such a dramatic difference. These things should be swapped out every few years. I took a short trip on the highway, from one entrance to the very next exit and man is my car happier. Got boost to 10.5 PSI and no issues.

Next plans are a new leakdown and compression test to compare with the original and install the new AFR.

I'll post a log and a LV later tonight.

 

Good to hear. Two things:

1. I don't think you need to redo your compression/leakdown test. The installation of these new parts will not affect the results.

2. Was 10.5 psi the max boost you hit? Cause the stock tune has a max target boost of around 13.5 psi.

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It's better, but still getting the occasional FKC of -2.11. Around 10.5 PSI is the is the most I got it to in the space of road I was on.

Knock counter when I check it gets into the low teen numbers. My car is so much more alive now and I definitely will be replacing the MAF in my next car every 50K miles.

Next on the agenda is changing the AFR.

BtSsm_LV_20160331_2059.png.090cc68eaea9e1f48b0599184e169f03.png

ATT00004.jpg.7beaf7ac36afa8269a21fc10857b10ea.jpg

ATT00000.jpg.c8334f8aca173812a95d8c44a49b6e3f.jpg

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The GrimmSpeed TMIC and the Turbosmart BPV. That's it intake wise.

I have a new issue now. On initial startup cylinder 4 will misfire once. This is a repeatable issue.

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You mean you have a count of one on the roughness counter for cylinder 4 right when you start the car? If yes, I would not worry about it. However, if after 30sec to a minute of idle, you begin noticing the count incrementing or staying steady in a given cylinder, then you would need to figure out why.
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If having one count of misfire on initial startup is a roughness count then that's what I have. It counts as one on cylinder 4 and then it goes away after about 10 seconds.

I still get knock counting up to double digits and the occasional warning of FKC -2.11.

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Seriously, you can completely ignore the knock counter's number entirely. The knock sensor will _always_ pick up random noise, and often it will increment the knock counter. If you're at a low enough load that all knock correction is turned off (under 0.8g/rev I think is the stock number), then the knock counter will increment but the ECU won't pull timing (knock at such low loads isn't really damaging to the engine, and likely it wasn't real knock either).

 

As for the FKC, I'd also expect occasional 2--4deg numbers pulled there. Much of the time, right when you cross over the knock correction threshold (again, IIRC the stock number is 0.8g/rev for FKC to be enabled), your ECU might also detect what it thinks is knock and it will pull 2 degrees of timing. If that's all you're seeing (i.e. no FKC under heavier loads/boost), you're in good shape. Keeping the knock correction at 0 ALL the time is just unrealistic.

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I'm getting the knock warnings at low loads and coming off throttle. Boosting and under a higher load hasn't revealed a knock warning recently. Though, I am keeping vigilant for it.
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I want to make a correction to my last post and bring in some new information. I got up to 11 pounds of boost on WOT and didn't have an issue and while coming off throttle FKC went to -2.11 and FLKC was at -1.40. Car is otherwise great. I have a log, but the phone that BtSsm is charging and I'll get it on here tomorrow.
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http://legacygt.com/forums/showpost.php?p=5369062&postcount=120

I'm keeping a copy of that pic for future "what to log?" posts ;)

Are you logging any other params w/o gauges?

No need to monitor VVT angles? (Edit, saw the update)

I guess if they're healthy a monthly/quarterly check would suffice...

 

Actually, I do have an additional parameter that I think is also important to view: boost target. I began looking at this one live on my 06 a month ago on a daily basis and noticed that I consistently meet the target which is great. However, I began doing the same on my 05 two days ago and noticed that I only reach max boost levels 2.5 psi lower than target boost when close to wot. I have actually never met target boost yet... So, time to investigate.

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I'm not a tuner, but here are my observations...

 

Regarding your Fuel correction, that +8 in the 40+ g/s column is a bit extreme. Possible pre-turbo intake leak? It would be good to get that down to a normal number (let's say under 2.00). It could contribute to some of the timing pull you're seeing. btw, please don't reset your ECU or your AFR under boost will go 8% leaner under the current circumstances.

 

Regarding your Timing correction, I see 2 things going on in that table:

 

1. The -2.80 at high rpm and high load: This is probably something that you should try to eliminate. Knocking under boost is not desirable. Possibly fixing your fuel issue above could remedy this.

 

2. The timing pull going right across at 2600rpm: I'm guessing that this is some sort of false knock being caused at this rpm. I had something similar that got worse like this when I was trying to optimize my VVT tables. When I put the tables back, the timing correction nearly disappeared, but I still get a little sometimes right at that RPM. My guess is that the variable intake cam sprocket gets a little "chatter" at times. Yours could be different, but mine appeared to be "false knock".

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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Those LVs make mine look tame by compairson. Definitelty best of luck sorting it out. I've been gone for a few days, but things have averaged out to the LV here. Car still runs great, but I may be selling it. I got approached by an interested party who wants it for 10K.

BtSsm_LV_20160405_1652.png.853af93e312f6cdae078998c6afe5388.png

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05LegacyGTGa, what's your FLKC at? Just to compare mine is 0.00, but every now and then it'll get a quick one time reading of -1.40. Very uncommon for it to happen for me.

Also, did you find any leaks?

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  • 3 weeks later...
  • 1 month later...

What's your intake setup like, stock?

 

If stock, reset your ECU, let the car re-learn for 80-160 miles and check LVs periodically (say at 50 miles, 100 miles, etc.) If they don't stabilize - something is still off mechanically or with your MAF/MAP sensors.

 

Remember - LVs are great but they are merely a snapshot, a learned average correction the ECU learns and applies under certain conditions (not always, but often enough).

 

As a side-effect, LVs can and will fluctuate a bit especially as seasons change (ambient conditions), fuel composition changes (summer/winter blends, more/less E* and water content, etc.), fuel system components age, sensors age, etc. and of course directly after a battery pull or ECU/TCU reset. This is normal.

 

If the LV snapshot consistently shows you fueling errors (Fuel Learn range adjustments) and/or Timing errors (pulled or added timing in certain cells), then like Heiche recommended, what you want to do is log and use the logs to dial in your tune to stabilize the LVs.

 

The idea isn't to get them to be 'perfect' (say IAM 1.0 and 0% Fuel adjustments in all ranged, 0 degrees pulled in all load cells).... but to get them within some reasonable thresholds regardless of season and other variables.

 

Say +/- 5% for Fuel Learn A-B

Say no more than 1-2 degrees of pulled timing in a handful (or less) load cells (ideally low load, low RPM, out of boost (if applicable)).

 

General rule of thumb is its typically better (read: safer) to have fuel subtracted in the LV table (meaning the ECU has learned to remove a bit of fuel).

 

So if you can't dial your MAF in so that you can stay within the +/-5% (or best of all +/-2% for all ranges - try to build a MAF curve such that fuel is either +/-5% down low (Fuel Learn A, B) and 0 to say -4% up top (Fuel Learn C, D). This will be safer than running lean (say +5 or +10% up top in Fuel Learn D and beyond under boost and WOT).

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Here are my most recent ones. I remember the guy I bought it from telling me it needs to be driven 50 or miles after the battery has been unhooked for it to relearn. Maybe its still just doing that....

 

27416054790_354eaee8bb_z.jpgBtSsm_LV_20160614_1950 by kornfan891, on Flickr

 

27593675612_2b7727b263_z.jpgBtSsm_LV_20160614_1936 by kornfan891, on Flickr

 

27082029904_b153262a22_z.jpgBtSsm_LV_20160614_1807 by kornfan891, on Flickr

 

27694613785_080485cd46_z.jpgBtSsm_LV_20160612_1935 by kornfan891, on Flickr

 

27593675682_607538986d_z.jpgBtSsm_LV_20160612_1803 by kornfan891, on Flickr

 

27082029944_977e865e1d_z.jpgBtSsm_LV_20160612_1748 by kornfan891, on Flickr

 

27416054900_cc1c775149_z.jpgBtSsm_LV_20160612_1238 by kornfan891, on Flickr

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