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Hey fellas/fella-ets,

Curious if this is a known quantity in the ecoboost world and if any of you have found a way to combats this .


Under very certain conditions I am experiencing rattle back knock ( piston slap )
It only happens between 25-3500 rpm.
ONLY while feather the throttle ( next to no input )
Goes with out saying, no load on the motor

And
Only while holding a gear in manual mode.

I have had it with both motors
Old and the new one,
Didn't think much about it with the old one,

However while breaking the new one in I am hyper sensitive to all sounds and vibrations while we get it sorted out.

The moment the slightest bit of load is added its gone.

I did just reach out to Torrie on the matter, but I thought I'd ask you folks if anyone has found a solution or Yada Yada, and etc. To this.


Thanks!
I think Justinjs is on it, I bet you 100$ is turbo wastegate rattle or NVH. I have Turbo wastegate rattle on my stage 2 turbos, and I had it on my old turbos. I’m not sure I have heard an Ecoboost that doesn’t have some sort of rattle like that. The raptors have some kind of NVH noise that’s very noticeable too.
 

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Could you put a couple of springs on the wastegate actuators to temporarily put a soft load against the slop in the linkage, and then go test to see if the sound is diminished or gone? Just to rule it out?
I’m not sure you could, the noise can be internal, inside where the flapper is. It’s usually in there and on the outside where it links to the elbow piece.
 

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Pretty sure I've got this too. It only happens before I get to operating temperature.

Is the waste gate rattle something to be concerned about? At least if a wastegate falls apart the chunks hit the Cats and not get sucked into the intake right?
Yeah. Haha, no, it’s not like it’s a super bad thing, just kinda obnoxious. It just means the linkages aren’t as tight as they used to be. It still functions just fine and probably will for a long long time, but it rattles like a little rattle snake under there. I’ve never heard of anything coming apart. If it did, then yeah you’re right, it would just go into the cat, and the wastegate would be wide open so you wouldn’t blow your engine up or anything.
 

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Sound theory,
but
In this case this isn't wastegate rattle.

This happens at any temp.
((( but only under these exact conditions) )
ONLY under no load, 2500-3500rpm.
Holding a gear in manual
And feathering the throttle down to almost no input.
And it sounds almost like starting a diesel cold.
(Piston slap) there is a name for it. Something something back rattle knock etc.etc.

It's the pistons more or less free floating @ the exact rpm with out and work being done.
And the piston rocks in the bore.

I am trying to see if this is something folks have tuned around in the past. Just ignore it .

I am wondering if it's a parameter in the original software that a tuner would never look at, and just wasn't quite sorted from the factory.

It's only in manual mode

It did this with the old motor too.
My wastegate rattle happens at any temp as well.
But, you might be dealing with NVH. Is there a metal heat shield buzzing against something that you can see?
 

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What's the knock sensors saying in that exact scenario?

Fortunately it isn't normal to be at 3000rpms no-load.
No.
This is not a tinni sound .
It sounds like a diesel. It's a hollow sound.
This is a sound clip of piston slap.

hmm, interesting. I may have that on my truck too, just initially on startup I’ll get a very similar sound.
 

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Piston slap (not to be confused with detonation or pre-ignition) is most likely to be heard in an engine that has forged pistons or one that was set up with the wrong piston to bore clearance or flat worn out. If they have the wrong clearance they can make noise from the get-go. Which one of these fits the bill? Just sayin'
So if I’m hearing that sound just in cold start, the 2.7 uses forged pistons I think, so there’s the answer.
 

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I wouldn't even venture a guess without listening to it firsthand. No guarantees without looking at piston skirts and then measuring the pistons and bores. I'm not suggesting this but bearing knock and piston slap can also sound like one another at first. Worn rod bearings soon get a very distinctive sound and are most often noticed at a lower RPM.
I don’t hear any odd sounds while driving around. It’s just at startup. For all I know it could just be the timing chain a little dry for a few seconds till oil lubricates it.
 

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Have you listened to either one of the videos. I attached?

Did yours sound anything like it does in the videos?


I don't think it's improper internal components,

I do think there is something odd here tho.
I just listened to your video. Definitely not turbo wastegate rattle or NVH. That definitely is something in the engine itself. I’m not totally sure what it would be though. You should hear the noise all the 2.7s make while idling. It’s nuts, and when you take the oil cap off while it’s running it literally sounds like a metal on metal clunking sound. But it’s apparently completely normal lol.
 

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It took awhile for me to get accustomed to all the sounds these things make and pin point what they all are , so when I do get an abnormal sound I'll be able to identify it.

Idk,
This Is an odd one.
Thanks for your input though,
Much appreciated.
No worries man! That’s what we are here for.
 
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