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2016 Forester XT
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33 Posts
Discussion Starter · #21 ·
Still trying to figure this out. Tried the thicker oil test but it made no difference.

I've mounted a camera in various parts of the engine bay in an attempt to get a good recording of the sound, but when I play it back I can't hear it. Compared to inside the cabin where it's very noticeable. Could be flexplate or torque converter? It actually sounds similar to this...

Although I can't reproduce it in park or neutral and it's not quite as obvious.

Made myself a smoke tester to try out on the weekend, and will do another oil and filter change as well as an upper engine clean.
 

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2016 Forester XT
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33 Posts
Discussion Starter · #23 ·
No not really, my noise is more metallic, the other way to describe it would be like the sound a rattling catalytic converter makes when it's falling apart inside. Except the noise isn't there when idling or cruising.

I'll try and get a clip from in the cabin to share.
 

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2015 Forester 2.5i Limited CVT
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1,491 Posts
I’m hearing the same thing. It’s very intermittent and not very loud but I can hear it.
gasoline?
 

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2016 Forester XT
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221 Posts
The pinging is very pronounced on initial acceleration but only lasts a second or two. Sometimes there is a hesitation as well if facing up hill.
It just occurred to me that what you might be hearing is the torque converter lock-up. Mine has always done this.
 

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2012 SH Manual Diesel
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790 Posts
No not really, my noise is more metallic, the other way to describe it would be like the sound a rattling
The clip that @bigfella posted, is definitely typical and characteristic of 'pinging' or 'pre-ignition'.

However, with the sound clip you posted, I wouldn't typically describe as 'pinging' or 'pre-ignition'. With minor and intermittent causes, I wouldn't expect pinging to be necessarilly evident at idle, or when revved in neutral, as there is no load. If pinging at idle or stationary, there's likely some major timing issue, or heavy carbon deposits etc.

If a lighter 'clacking' sound (not a deeper 'clanking', like bottom end), it may be fuel injection system related (worn injector, rail pressure relief valve, maybe high pressure pump). See if there is any rhythym or speed, that coincides with RPM or Cylinder firing.

Just watched another good diag vid. from SMA. Maybe see if you can adapt his Mode 6 technique to your situation. Would be handy if the 'Power Balance', feature was available.
 

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2012 SH Manual Diesel
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790 Posts
I have hear a tack tack tack sound, but i don’t know if thats from the steering wheel turning, or the camera moving.

Is it the tack tack, kind of creaking sound; that repeats 5-6 times; is kind of slow, but changes speed ever-so-slightly, not really in rhythm or speed with the rpm?

Exhaust manifold leak, or leak around turbo flange???? Maybe it occurs when the engine rocks on acceleration, but once acceleration is over the manifold seals back up (may also tie in with the downhill occurance.

Does your model have the engine pitch stop bracket? Maybe check that its installed, tightened up, or if bushings are in good nick. And maybe run a spanner over the exhaust bolts/nuts.
 

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2016 Forester XT
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33 Posts
Discussion Starter · #29 ·
Thanks for taking a listen Dogs. No it's not the creaking sound when turning the steering wheel. It's only audible when the *rattle text flashes up on the screen (3sec, 12sec & 21sec). Sounds like nuts and bolts in a tin can and only lasts for a second. It is very faint in this video, much easier to hear in the car.
 

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2012 SH Manual Diesel
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790 Posts
This is what every garage needs.

 

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2016 Forester XT
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221 Posts
Listened to your video several times. Have you checked the bracket that attaches the exhaust pipe to the CVT? These are notorious for breaking and rattling.
 

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2016 Forester XT
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33 Posts
Discussion Starter · #34 ·
Yeah I have Mike, had the whole exhaust off from the cat back, checking for loose bolts and heat shields. Was all fine.
 

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2016 XT
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283 Posts
Would you say it sounds like a chain rattle? if so, if I pull away from a stop with a bit of urgency, read, trying to beat someone of the lights under stealth.. lol. I get a rattle which I suspect could either be the chain in the cvt or the timing chains crying "EASY NUMNUTS"
 

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2016 XT
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283 Posts
I’m hearing the same thing. It’s very intermittent and not very loud but I can hear it.
gasoline?
Yeah sounds like you need to go up a grade or two and or need a upper engine decarb.
 

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2016 Forester XT
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33 Posts
Discussion Starter · #37 ·
Would you say it sounds like a chain rattle? if so, if I pull away from a stop with a bit of urgency, read, trying to beat someone of the lights under stealth.. lol. I get a rattle which I suspect could either be the chain in the cvt or the timing chains crying "EASY NUMNUTS"
Interesting! Yes it does make the kind of sound a bike chain makes when rubbing against something. However mine has progressed to doing it almost all the time now, not just when pulling away quickly.
 

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2016 XT
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283 Posts
When exactly does it happen? If you can do a video with it happening in all its instances (pulling away, driving etc without the extra noises of indicators, steering wheel sliding through hands etc that may help more. I'm starting to think it may be a cvt problem?
 

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2016 Forester XT
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33 Posts
Discussion Starter · #39 · (Edited)
Got myself a Tactrix cable and took some logs this morning with RomRaider. The two things that immediately stand out for me are
  • Fine learning knock correction was way down to -13.5 and only went up to -9
  • IAM was down to 0.4375

It happens on take off, or at very low speeds when accelerating briskly. Doesn't matter if the engine is cold or warmed up. It definitely is easier to reproduce when facing downhill, no idea why.

I took another video too, I can hear it clearly with headphones on. 11 second mark.
 

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2016 XT
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283 Posts
These seem to knock for nothing, but I think most of it is caused by how the cvt works, I have a mild tune on mine and I get knock in the 10’s when cruising which drops DAM. But a couple of pulls and its back up to one. From what I can gather the stock tune is worse and the IAM/DAM numbers are never close to one, As long as it doesn’t knock on full throttle its probably nothing to worry about.

Are all of the heat shields on the exhaust and manifold good? Tight etc, no little stones trapped in there? it sounds like a heat shield rattle.
 
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