BTSSM says I have knock

[scoobyskier]

This turned out to be a very informative thread.

[Soarin]

I will check for leaks on the weekend, again. No more misfires counted yet. I got one knock counter today on the trip to work. Nothing on the trip back and this is roughly a 5 mile trip each way. Starts up with zero issues though. The LV is concerning and I'm watching over it and all the rest.

 

I do have some sad news. If it really is the shortblock then I have some really bad news. I can't borrow any more money from relatives and I can't get a loan financed yet. No one is approving me although I have excellent credit.

So, the car is for sale as is and with all of the mods. Lots of all new stuff. I'm farming it out and I'd like a fellow Subaru enthusiast to get it than trade it in or sell it to someone who may not appreciate it the way I did. I really am in a bind.

The so so part is that I may not be getting another Subaru. I can't afford a Forester 2.0XT yet and in all honesty the Mini Countryman S has a nice 36 month lease offer.

[Soarin]

Now, this is just a thing to put out there. My TGVs have different voltage readings. Left always reads lower than Right. Could that be anything? While I'm here learning about all of this.

 

Also, HUUUUGE thank you to all of you guys. There's no way I could keep as sane and in one piece without all of the information and advice. Thank you!

[xt2005bonbon]

SO, if you are not registering any count of misfire at idle (warm or cold) in any cylinder, and you are not burning oil, I would strongly believe your engine is just fine. You just need to carefully look for vac leaks. Do a smoke test if you can. Then, get the car tuned and enjoy it!!!

 

Side note: can you also log your VVT L and VVT R? These two parameters should always be matching each other. Please report on that too.

[Soarin]

That is amazingly good news. I've been so busy with work and I'll take any chance to save it as a whole. I'll be under the hood for vacuum leaks on Saturday. I'll chase after any sort of hope.

I will post VVTL and VVTR paramaters after work. The left one has always read as lower that right. Sometimes as low as 0.02 volts. Sometimes a little higher.

[xt2005bonbon]

Yeah. log also the VVTL/R in degrees. These should be available.

[Soarin]

VVTL/R degrees is the same on both sides at all sorts of rev ranges. I looked for the vacuum leak. Still can't find it on a visual and physical inspection. I'll have to get a smoke machine. Where the hell could one be? I almost feel like I should pull up the entire intake manifold to find it. Hoses look good and I can't hear anything either.

I almost feel like it's a valve or something since the leak down test for cylinder 4 said it has an 11% loss. Should I get another leak test? Maybe at the dealer?

BtSsm_20160314_194535.csv

BtSsm_20160323_171654_knock.csv

BtSsm_20160323_171804.csv

[xt2005bonbon]

If VVT L/R are always synchronized, then that's great. At least, you know the oil control valves are working as they should.

 

Regarding a valve issue on #4, if it was the case I would really think it would show up as a misfire at idle. FYI, I suffered from an exhaust valve that was leaking on cylinder 2. It would show up as a high count of misfire on that cylinder during warm idle only. But you said you do not have any misfire counts, so you should be good to go there.

 

Unless you can do it yourself, just pay 100$ or so at a reputable shop that would perform a smoke test. If no leaks are to be found, I would get in touch with a tuner at that point.

[xt2005bonbon]

I've been looking at your logs...

 

How many miles does your car have?

 

How old are your o2 and MAF sensors?

[Soarin]

Thank you for looking at the logs and understanding things I am doing my best to understand and figure this out on my end.

Sensors are all original and I cleaned the MAF sensor thoroughly. The car has just a little under 104500 on the clock. Original engine.

I'm working on seeing if someone I know has a smoke machine to borrow. That or I can get one cheap.

[solidxsnake]

With that many miles, it's possible your front O2 sensor is on its way out. It seems they can give false readings without throwing a CEL for quite a while. I'm at 132k on the stock one, but I have a feeling mine is also on its way out, as my fuel trims are not where I'd expect them after a good tune (and they were fine after the tune). Might be something worth looking in to.

[xt2005bonbon]

Thank you for looking at the logs and understanding things I am doing my best to understand and figure this out on my end.

Sensors are all original and I cleaned the MAF sensor thoroughly. The car has just a little under 104500 on the clock. Original engine.

I'm working on seeing if someone I know has a smoke machine to borrow. That or I can get one cheap.

 

How did you clean the MAF sensor? Just to make sure, the MAF sensor is where the red arrow is pointing, not the green arrow. A lot of people confuse the two.

 

[Soarin]

I cleaned the MAF exactly where it needed to be where the red arrow is pointing.

[xt2005bonbon]

OK. That's good. So I gather you sprayed some MAF cleaner in that cavity then, and did not touch the sensor with a q-tip or something. Just making sure .

[xt2005bonbon]

I will also add this for your info and others:

the past year, I've been chasing like mad boost leaks on my 06 as my fuel trims were always becoming way negative (i.e. close to -15%). It was driving me nuts as I could not find any boost leak.

So, one day, I had the engine idling in my garage, and while I was holding my phone in one hand with the btssm app running, I 'gently' wiggled the MAF wiring harness. And all of the sudden, the trims started to correct themselves. It was obvious. I repeated this procedure several times on different occasions to confirm, and concluded that the so-called boost leak issue I thought I was having, was actually a MAF wiring harness issue! food for thought..

 

My 06 has 140k btw.

[Soarin]

With that many miles, it's possible your front O2 sensor is on its way out. It seems they can give false readings without throwing a CEL for quite a while. I'm at 132k on the stock one, but I have a feeling mine is also on its way out, as my fuel trims are not where I'd expect them after a good tune (and they were fine after the tune). Might be something worth looking in to.

 

I can get that O2 sensor replaced and see where it goes. How far were your fuel trims off? Were they as far off as mine in the last posted LV?

 

I'll try the MAF today after work and see where that goes. I've never had an issue with it before. The only time I did was when a K&N filter gummed it up and caused it to throw a code years ago.

[Soarin]

I just tried the MAF harness jiggle and the Voltage didn't really change. Fuel trims are pretty much where we left off and I have a new log I can upload in an hour. I got the car smoke checked and there's zero vacuum leaks. This car is sealed up tight. I'm out getting a few essentials and can keep logging and getting new LVs, but so far no knock warnings. I took the counter off because of the anxiety it caused.

I would also like some clarification on the front O2 sensor and how that can affect my fuel trims. Plus, why can't I monitor it?

[solidxsnake]

I just tried the MAF harness jiggle and the Voltage didn't really change. Fuel trims are pretty much where we left off and I have a new log I can upload in an hour. I got the car smoke checked and there's zero vacuum leaks. This car is sealed up tight. I'm out getting a few essentials and can keep logging and getting new LVs, but so far no knock warnings. I took the counter off because of the anxiety it caused.

I would also like some clarification on the front O2 sensor and how that can affect my fuel trims. Plus, why can't I monitor it?

 

Monitoring your AFR is monitoring your front O2 sensor, more-or-less. If it's inconsistent and bouncing around (something to check in a log), or your real-time fuel correct is also oscillating, either you have a MAF or an O2 sensor issue (though I suppose there are other causes as well).

 

I would disregard the knock warnings, and just keep an eye on your FLKC and DAM. Or, change your knock warning threshold to something lower than, say, -4deg or so. -2deg at low load/RPM is pretty common.

 

I haven't replaced my O2 sensor, so I'm not sure if it's actually causing me any issues, but my D fuel trim has been hovering around -8%, which I think is causing my engine to run leaner than I'd like under boost in open-loop. I very rarely drive in a way for it to learn much in that region (low load at a relatively high MAF), so I'm not sure how it got that low. My tune has been fine up until recently though, and not much has changed, so I'm thinking something is starting to go out.

[Soarin]

Just tested some things out with this log and IAM dropped to a staggering 0.325 and then went back up to 1.000 which is where it is currently. Did a bit of a pull on boost when a truck got behind me and I couldn't move over. I have a log of the knock which only triggered one warning. I was logging as I left the bookstore. I used to get two or three knock warnings before in a row a week ago. So, I don't know if my situation is improving or getting worse.

I want to monitor closed loop with BtSsm, but every time I select it the app freezes and I have to clear out it's data and reset it completely.

How much AFR bounce is considered normal? It likes to hover between 14.1 and 14.7 during driving.

I see that my fuel correct moves around as well. Other than a MAF or 02 sensor I wonder what else could cause it. Also, how much bounce in Fuel Correct % is considered normal.

Still no codes, just saying. I also told the Subaru dealer's service department my issue and they said no codes means a good thing and that the ECU is working out the issue. I know they're not going to help this time around.

I'm working on finding a trusted Subaru tuner locally who I can talk to in person. Not saying I don't appreciate the help and comments. I really do, but I probably should talk to a well established and experienced tuner in person as well.

BtSsm_20160324_181651_knock.csv

[solidxsnake]

Just tested some things out with this log and IAM dropped to a staggering 0.325 and then went back up to 1.000 which is where it is currently. Did a bit of a pull on boost when a truck got behind me and I couldn't move over. I have a log of the knock which only triggered one warning. I was logging as I left the bookstore. I used to get two or three knock warnings before in a row a week ago. So, I don't know if my situation is improving or getting worse.

I want to monitor closed loop with BtSsm, but every time I select it the app freezes and I have to clear out it's data and reset it completely.

How much AFR bounce is considered normal? It likes to hover between 14.1 and 14.7 during driving.

I see that my fuel correct moves around as well. Other than a MAF or 02 sensor I wonder what else could cause it. Also, how much bounce in Fuel Correct % is considered normal.

Still no codes, just saying. I also told the Subaru dealer's service department my issue and they said no codes means a good thing and that the ECU is working out the issue. I know they're not going to help this time around.

I'm working on finding a trusted Subaru tuner locally who I can talk to in person. Not saying I don't appreciate the help and comments. I really do, but I probably should talk to a well established and experienced tuner in person as well.

 

Yes, that's always a good idea.

 

For reference, I don't go a single drive without some feedback knock (i.e. something that will trigger a knock warning in BtSsm). Now, if I get a lot in boost (which I've never seen happen), then I'd be worried, but I often see it at very low loads, or on tip-in, or when hitting bumps in the road. Honestly, I'd ignore that and your knock sum counter (unless you've logged significant timing being pulled consistently under boost).

 

If your AFR isn't dropping below 14 under medium to heavy throttle, you've got some serious issues. Anything near 14 in idle-to-light loads is probably fine, but it should drop pretty quick once you've put a little throttle in. I see that it's not dropping much below 13.8 or so @ 25% throttle, but I'm not familiar with the stock map well enough to know if that's normal or not (it seems a bit high, IMO, but I'm far from experienced). You have a good amount of low-to-mid load knock (2-4deg FLKC at lower RPMs and loads <1.5ish g/rev), which is a little concerning.

 

Rule of thumb is that your fuel trims (the four values in a learning view) should be +/- 10%. The real-time fuel trims (fuel correct) should bounce around a little (say a percent or two at most) when you're at a steady-state condition, but not necessarily around 0 (though once your fuel trims are settled, it should be pretty close to 0). Keep in mind the way that works in closed-loop: your engine burns air/fuel, exhausts it, and the front O2 sensor measures how well the combustion occurred (i.e. rich or lean mixture). If the mixture was leaner than its target (higher AFR), it will add fuel to compensate in the future, vice-versa for a richer-than-target condition (lower AFR). If the ECU consistently sees that it's adding or subtracting fuel, it will start to "learn" and always deliver fuel (at a certain load/RPM range) accordingly. The "learned" percent are the numbers you see in your LV, the real-time number is your "fuel correct" in the logs. The sum of the two numbers tells you how much fuel your ECU added/subtracted at that moment in time in order to try and reach its target AFR.

 

You don't need to log closed/open loop... generally it's pretty obvious if you're logging fuel-correct as well. If you're above a certain load (I think on my car, once I hit 1g/rev, it goes to open-loop), you'll notice your fuel-correct will be pegged at 0 and not move at all... that means you're in open-loop, and the ECU is only adding/subtracting fuel based on the fuel-learn value at that point.

 

Did you reset the ECU after cleaning your MAF?

 

Also, keep in mind you have a 5EAT... those are known to trigger lots of false knock (I believe around where the torque converter locks/unlocks) in certain conditions.

[Soarin]

All of that is a lot of good information. I'll be finding a good tuner asap. My usual Subaru shop knows some people and this ECU tuning is a bit over their abilities. Although, they did detect the knock and through a leak down test they said cylinder 4 isn't happy and leaking 11%. They're just not sure from where. Knowing that felt like finding out I have a time bomb. That's that mid to low knock that has been there for who knows how long. Though, the compression check came back good.

Every time I cleaned the MAF the ECU was reset and it was reset after the shop did a compression and leak down test. (Last Thursday 3/17/2016)

I had learned the fuel trims were okay as long as they were within + or - 8 for a stock map. I think that comment is somewhere in this thread.

I've never gotten a knock count on a bump and I have a pretty stiff suspension setup. At least not that I noticed.

I see more now how changing the O2 sensor could help my situation out. The real time fuel trims are moving around a lot. I'll see more tomorrow on my drive to work now I know more of what to look for.

[xt2005bonbon]

Do you still own the stock airbox with stock filter?

[Soarin]

I have the stock airbox and I can get the stock filter from the dealer after work.

[xt2005bonbon]

Yeah. I'd be curious to see how the ecu will react if you replace that dry flow filter with the stock filter. Don't reset the ecu just yet after the change. Just observe the 'fuel correct' and 'fuel learn'.

If no changes occur, I would then go on checking if either the MAF or o2 sensors are at fault. Problem is they are not cheap..

[gimpydingo]

All of that is a lot of good information. I'll be finding a good tuner asap. My usual Subaru shop knows some people and this ECU tuning is a bit over their abilities. Although, they did detect the knock and through a leak down test they said cylinder 4 isn't happy and leaking 11%. They're just not sure from where. Knowing that felt like finding out I have a time bomb...

 

In regards to your compression and leak down. The comp numbers are great and leak down on 1 - 3 are as well. I know cyl 4 is the one that gets the beating with the heat, that could be part of the "issue". I didn't see it mentioned, does your car consume oil and if so how much? I wouldn't consider it a time bomb, obviously someone correct me if I am wrong.

 

EDIT: I see smoke test was already done. Thanks xt2005 I missed that.