Knock, knock!? I got it!

Well, my '11 LGT is not running right lately. Knocking and pulling timing on Cobb stg2 93, stg2 91, and stg 0. It obviously is not boosting right as well.

 

Can someone look over a few of these logs and let me know what they think? I have been checking for leaks, but can't find anything obvious. The car boosts and runs fine sometimes, but is obviously pulling timing due to knock at other times. It does not feel smooth nor is it fun to drive.

 

I have attached logs from Stg2 93, Stg 2 91 and Stg 0 runs. Keep in mind, after a reflash, and every time you switch the ignition off, 5th gen LGTs start out at either DAM=69 (Stg 0) or DAM = 80 (Stg 2), IIRC.

 

I have a RacerX TMIC (could explain lower boost levels) and full catted 3" turboback with stock muffler (axleback).

 

I changed some logging parameters today, so 91 Oct maps and Stage 0 maps may be a little different. Running on 93oct gas from BP and later Shell, winter blend, I am sure.

 

Any help would be greatly appreciated.

Stage 2 93oct 1.csv

Stage 2 93oct 2.csv

Stage 2 93oct 3.csv

Stage 2 91oct 1.csv

Stage 2 91oct 2.csv

Stage 0 2.csv

You really should reflash the map and do a pull in 3rd gear WOT from 2k to redline. Of course, make sure you can do this safely. These partial throttle conditions aren't optimal to tell us anything. Although, imo knocking about 1.3 calculated load makes me uncomfortable. Feedback knock is probably learned from a previous knock event but can't tell without knock sum.

See, this is the crux. All these logs are with WOT, but the throttle position sensor is not reflecting the accelerator position of 100%.

 

Has anyone had issues with throttle position not going to 100%? I don't think that is has much to do with the A/F Learning adding that much fuel? I seem to have two problems that are independent, no?

 

EDIT: Later logs have been switched to Accelerator Position to verify the position of it vs. what the Throttle Position was reading.

do a boost leak test to eliminate vac leaks as an issue completely. it's not uncommon for cobb ots stage 2 maps to knock even running 93oct on a 91 map. the DAM should always be 1. after a flash it will start much lower and then hopefully increase to 1 once the ecu gets out of rough correction mode. I suggest you get a quality tune and forget the ots maps, they're crappy even on a good day.

While DAM=1 after initial learning is true for Gen 4 cars, it is not the case with Gen 5 Legacies. DAM always reverts to .81 after ignition has been cycled. If all is well, it will quickly go up to 1. This process repeats everytime you restart the car. I think of it as built in safety to make your ecu more sensitive to issues that may come up.

 

Is TPS sensor supposed to output 1-5V depending on accelerator pedal input? Just did some logging and noticed that mine only goes to 2.9V, reluctantly at that.

 

Requested torque seems correct, but target throttle never goes up above 70%. To me, it means that the sensor is faulty. Thoughts?

 

I don't think that I have a boost leak, my vacuum is steady at around 21 inches of mercury. All the hoses are zip tied. Clamps are clamped down tight.

Two more logs that show throttle position vs. accelerator position, as well as target throttle and requested torque. It got really slow due to the number of parameters, but I wanted to see the throttle/accel logs. I am stumped...

 

Any ideas? Seriously, I talked to a few people already and no one has ever seen this. Wonder if the TPS is faulty, but in neutral, it goes to 100% when floored (row 57 and 88 show it - TPS and Accel 2 log); just does not go past ~70% under load. Could there be built in safety if knock is present?

Yes, these are not full throttle runs, but more less street driving with some WOT thrown in when possible.

 

Could the maps be corrupted? Or the AP or ECU be faulty? I am losing my mind?

Stage 2 91oct 3 (TPS and Accel) 2.csv

Stage 2 91oct 3 (TPS and Accel).csv

there's multiple throttle and accelerator position parameters you can choose from

there's multiple throttle and accelerator position parameters you can choose from

 

Could you please elaborate? Thanks!

Seriously, just limit your logs to the WOT pull. I seriously doubt you are under WOT for like a minute at a time. Here is an example. Short, sweet and to the point.

 

As for your throttle position issue, I have no idea what to say. Maybe a faulty TPS sensor or something.

datalog8.csv

As requested, here are two pull logs. One is in third gear, the other one is in fourth. Glad my driveway is really long, as I was doing 130mph at the end of fourth gear...

 

Goofy throttle position numbers are still there - and my MAF g/s fluctuate too.

Third gear pull.csv

Fourth gear pull.csv

Cobb just informed me that:

 

"The 10+ LGT has unique throttle tune that can result in throttle closing a bit when your foot it to the floor. This is primarily based on intake temps (colder temps can cause throttle reduction) or lower dynamic advance multiplier (DAM)."

 

I submitted these logs above to them for reference. Any ideas based on the two pulls?

No knock on the 3rd gear pull. 2 events of knock at line 22 and 24 in the 4th gear pull. However, the knock was in low load and probably due to the 4th gear low rpm pedal mash. But, you are doing the logging with a DAM of 0.81. So unless you have serious knock events that prevent you from getting to 1, you should do a 3rd gear pull when when that happens.

Need DAM at 1.0 prior to beginning log. Data is almost useless without that.

Here are a couple of logs from today, with DAM being at 1 and warmer temps. I also got 93oct fuel (winter blend) from a Mobile gas station last night. Pulls were done on Cobb's OTS stage 2 91ACN maps.

 

I think that the logs look a lot better. Are these cars really this sensitive to low temperature? Or could it have been fuel quality? There are still a couple of events of knock, but not during the main pulls. Or is my gas so piss poor, that I can only not knock on 91ACN settings?

Third gear pull - new.csv

Fourth gear pull - new.csv

Third gear pull and info fourth.csv

Fourth gear pull - after engine restart.csv

Looks good! I wouldn't be concerned about -1.40 knock. Even running a 91 oct map with 93 on a cobb ots map will still knock, just less than 91 on a 91 or 93 on a 93. You could ha e had bad gas. I had bad luck with mobil, i only run shell and irving 93 and never had my iam drop. The temps are not the cause of your DAM issue.

I think so too, but I am concerned about how quickly good turns to bad with my set up. Would really like to understand all the factors. A custom tune might shed some light on the issue. I plan to have it tuned soon, but need to decide where, as we don't seem to have a reputable local tuner.

 

DAM drops due to knock - but in the 5th gen, DAM always drops to .81 at start up. If no issues are found, it quickly rises to 1. 4th gen's DAM only drops after you flash and once it reaches 1, it stays there until you reflash or reset the ECU, or have knock.

 

I was wondering if knock is worse when temps are around freezing with my 5th gen - it seems that it is either that, or the bad winter blend. Or both...

 

Bill @ Cobb is reviewing my logs and has shared some neat info so far about the 5th gen LGT. Our ECU programming is quite a bit different than 4th gen that I used to have. I am more certain that I don't have a mechanical issue, as without any set up changes, the car is back to being almost knock free.

the ecu adds timing in colder temps(for better efficiency), and pulls timing at higher outside temps. perhaps when you reached a certain temp, it was adding too much, and knocked a little too much for your DAM to remain. I zero out the cold timing compensations so when I tune timing, the ecu won't add any more than I set in the table, only pull when it's really hot out. In the 4th gen, the ecu can add up to 2* more timing if it's real cold out which could cause issues if your setup is irritable. a custom tune is pretty much the best deal here, and more reliable.

Gas. Winter blend. Finicky car (some just are). A custom tune should work it all out. It is an OTS map and for a car that Cobb has had little feedback on as it is. Normally if fuel is good, colder equals more power.

Thanks guy. I appreciate the help. I hope that all my troubles go away once summer gas is here in a month or two.

I told you to get an Infamous tune a long time ago. Are you still going to come visit me?

I know, and you were right!

 

Not sure yet when, but I am planning on making my way up there. Hopefully once the weather gets better. We will be getting together here with the old Subaru bunch sometime this spring, so if you feel like taking a drive down, it would be great to see you.

Quick update: I added the white bubble silencer to my airbox (it was taken out by the previous owner) and the a/f trims are much better. Lack of it must have been throwing my MAF scaling off like nobodies business. I can't believe the fuel correction difference now; hardly any fuel gets added. That's the good news.

 

The bad news is that I still have a little bit of knock here and there. It must be the winter bland gas. Can't wait for spring to get here to find out if that really is the case.

 

These are still Cobb OTS Stage 2 ACN91oct...

3rd gear pull - airbox fixed.csv

Another 3rd gear pull - fixed airbox.csv

4th gear pull - fixed airbox.csv

less than 1 degree of knock, relax.

Other logs during normal driving (that I did not post) are showing knock up to 2.8 deg, so I don't think that I am fully out of the woods yet. And remember, these are on uber conservative map. Custom tune, here I come! Thanks again for your help.

I'm not familiar with 5th gens so let me ask this first: you said the DAM starts out below 1 and then rises to 1 eventually.

 

Does that mean your learned knock table is reset every single time you restart your car? That seems a kind of stupid.... Hmm.

 

edit: I don't believe you're correct. A quick search makes me think that it's map dependent.