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So what's the deal with the 2K-rpm rattle?

GT Pony

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Not saying it even needs to be fixed, although by now I would think some mechanic or engine builder would have figured out what is causing it.
IIRC, wasn't it LMR (?) that said/claimed it was non-round cam-chain sprockets? Don't quote me on that. Could be, if manufacturing QA is crap on making perfectly round cam-chain sprockets.
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Elp_jc

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Hey gang, just changed the oil, and took the car out cold to check the 2K rattle more carefully. I noticed something new, that I haven't seen mentioned before: The rattle only happens when ACCELERATING, even a tiny bit. But stop accelerating, meaning just holding speed at the same rpm, and rattle stops. Press the gas pedal a tiny bit more, and the rattle is immediately back without the speed increasing right away. So it's not just rpm dependent, but rpm AND accelerator dependent. Not sure what we can eliminate by that, but I'm suspecting the high-pressure fuel pump is the culprit more and more. Could be the clutch, like some folks have mentioned, but with this finding, I'd eliminate it. Comments welcome on that.

Finally, also noticed when engine was hot the rattle rpm RANGE diminished... but the rattle itself was almost as loud as when engine was cold. Curious how louder it'll be when it gets actually cold. Some folks said it was MUCH louder, so not looking forward to that. Ha ha. Hopefully we're closer to find the cause of that stupid rattle, by process of elimination :).
 

ice445

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Hey gang, just changed the oil, and took the car out cold to check the 2K rattle more carefully. I noticed something new, that I haven't seen mentioned before: The rattle only happens when ACCELERATING, even a tiny bit. But stop accelerating, meaning just holding speed at the same rpm, and rattle stops. Press the gas pedal a tiny bit more, and the rattle is immediately back without the speed increasing right away. So it's not just rpm dependent, but rpm AND accelerator dependent. Not sure what we can eliminate by that, but I'm suspecting the high-pressure fuel pump is the culprit more and more. Could be the clutch, like some folks have mentioned, but with this finding, I'd eliminate it. Comments welcome on that.

Finally, also noticed when engine was hot the rattle rpm RANGE diminished... but the rattle itself was almost as loud as when engine was cold. Curious how louder it'll be when it gets actually cold. Some folks said it was MUCH louder, so not looking forward to that. Ha ha. Hopefully we're closer to find the cause of that stupid rattle, by process of elimination :).
After removing the sound tube I don't really notice the 2K rattle anymore. It's still there obviously, but you have to put the windows down and try to hear it now. Personally I don't care, if the engine breaks then it breaks. I have 6 years/75K miles of not having to worry about it.
 

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Elp_jc

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I had my timing chain tensioner replaced under warranty and rattle went away
That's interesting. I ruled that out since my engine was built after the cam chain tensioner TSB cut-off date of April xx (my engine was built in May 30, and car in August 09). So just the tensioners? I assume you got both changed, right? You have 2 cam chains from the crankshaft, so you need 2 tensioners. Then you have 2 little chains from the exhaust cam to the intake cam, but not sure if they have another tensioner each or not (probably not). You can actually see both chains from the oil fill hole.

After removing the sound tube I don't really notice the 2K rattle anymore.
I don't notice it either... unless I turn everything off, and exhaust in quiet mode. So I'm not worried about it all either, but the engineer in me wants to know what the hell is causing that rattle :D. If I maintain speed, it's quiet. As soon as I increase throttle even by a minute amount you don't feel, the rattle immediately resumes. meaning it's being affected by the load on the engine, even when it changes minimally. It has to be either the cam related (including tensioners and phasers), or fuel pump (mechanical one) related IMO. Wish the engine experts would chime in with exact possible culprits :).
 

Sivi70980

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Another thread in a galaxy far away someone data logged in the RPM range and said the fuel system transitions at that same range. Good enough for me and that's why I call it the DI rattle.
 
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Elp_jc

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someone data logged in the RPM range and said the fuel system transitions at that same range.
That'd explain the DI high-pressure fuel pump theory. Assuming it's the DI pump, what can be causing the rattling? It can't be the camshaft physical contact, like I thought it could be before. Not only is the frequency of the rattling higher, but the noise stops if you stop accelerating, so it can't be it, since the cam keeps hitting the DI pump at a steady throttle. The only other possibility if the DI pump is the culprit is cavitation, no? Or is there any other possibility??? Seems weird that Ford didn't catch that. I've owned quite a bit of DI vehicles by now, and none have made that noise, including my ex-F150 3.5EB, also with dual injection.
 

ice445

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That'd explain the DI high-pressure fuel pump theory. Assuming it's the DI pump, what can be causing the rattling? It can't be the camshaft physical contact, like I thought it could be before. Not only is the frequency of the rattling higher, but the noise stops if you stop accelerating, so it can't be it, since the cam keeps hitting the DI pump at a steady throttle. The only other possibility if the DI pump is the culprit is cavitation, no? Or is there any other possibility??? Seems weird that Ford didn't catch that. I've owned quite a bit of DI vehicles by now, and none have made that noise, including my ex-F150 3.5EB, also with dual injection.
I don't think it's an actual rattle, I think it's just resonance/harmonics that manifests itself like a rattling sound as it passes through the pump housing/engine mounts. Just like exhaust drone, these harmonic effects generally only appear at a certain RPM range and then stop. In the case of this one, I don't think it actually goes away when you stop accelerating, it just changes tone somewhat. Likely because the motor has shifted back the other way. That's my theory and I'm sticking to it.
 
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Elp_jc

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Makes sense. By the way, if you accelerate even modestly, it goes away. It's only there when accelerating lightly, and within that rpm range, which is, at least on my car, from about 1,800 to 2,800 rpm. And it changes as the engine heats up, narrowing up. The good news we already know it doesn't affect engine longevity, so it's just an annoyance. And as far as wanting to know what exactly is causing it, just curiosity :). But I think we pretty much narrowed it down to the DI pump. And that means pretty much all cars make it, but some owners still haven't heard it yet. I was one of those... until I read a stupid thread about it on this forum. Ha ha.
 

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Sivi70980

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Makes sense. By the way, if you accelerate even modestly, it goes away. It's only there when accelerating lightly, and within that rpm range, which is, at least on my car, from about 1,800 to 2,800 rpm. And it changes as the engine heats up, narrowing up. The good news we already know it doesn't affect engine longevity, so it's just an annoyance. And as far as wanting to know what exactly is causing it, just curiosity :). But I think we pretty much narrowed it down to the DI pump. And that means pretty much all cars make it, but some owners still haven't heard it yet. I was one of those... until I read a stupid thread about it on this forum. Ha ha.
Sometimes the blue pill really is bliss
 

Ruby_Ruby19

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I'll just apply my logic to this situation. My car has both the tick and rattle.

The rattle is around 1700 to 2200 rpm. I read a fueling thread a while ago, and saw something about cycles, and fueling transitions...way over my head but it came down to something DI related. "Please hang in there with me there's a point to this"

The dreaded "tick" is something the car has had since I rolled it off the showroom floor. Characteristics are as follows.
1. Starts 3 to 5 minutes after a cold start
2. Sounds like a mechanical tick/tap
3. Dissappears after several minutes of driving.
4. Only audible at idle below 1k rpm

I brought the car to a trusted shop, they observed it, and the response was this. "If its rod knock, it wouldn't go away With RPM, should get worse. If its a wrsit pin or piston issue it wouldn't go away. If its a true mechanical issue or internal component issue - it wouldn't appear after start up, and go away after driving"

They went into more detail on the DI pumps and shit over my head with fueling, but my simple mind can apply basic mechanical facts.

I don't worry about it- I run the car hard, i don't baby it, its been a strong running car, and I am certain it's not anything to lose sleep over. I was just at a grudge night and was talking with a owner of a Whipple 2018. His ticks and rattles and it runs low 10's and has 30k miles. There is countless other cars in the same boat.
 

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I've read about the infamous '2K rattle' many times here before, but never heard it... until today, so probably made it since mile 1. Had to leave the house early, meaning in quiet mode, so I heard the damn rattle. On my car, it's closer to 2,500 rpm than 2K, but I assume the others are the same, and just called the '2K rattle' for simplification purposes. At any rate, that damn rattle is not subtle at all. And it lasts for a good 300 to 400 rpm, so its 'band' is not that narrow. Here are my questions:

1. Does anybody know what the hell causes it?
2. Does it happen cold, hot, or both? If both, problem is if you're on the freeway or highway, you'd be cruising right in that rpm range, so hard to avoid without downshifting to 5th, at which point car woulf consume more gas, have less range, and make more noise (and have more wear too). If only when cold, it'd be easier to avoid. Still heard it about 10 minutes into my trip. Oil possibly not up to full operating temperature, but close. I think it was less loud, but couldn't concentrate on that due to traffic requiring my attention.
3. Do you guys think it could be detrimental to the engine in the long run, to try to avoid that rpm band, or doesn't really matter?

The good news is the majority of owners have it, for what I can tell now. The bad news is why Ford hasn't fixed it after so many years? It can't be good. Maybe not detrimental, like the 1st gear clunk on motorcycles with a wet clutch, but sounds embarrassing. I'm going to leave the exhaust in sport most of the time, so I don't have to hear it. Ha ha. I don't feel any vibration on the engine or gas pedal, etc. That's good news, I guess. All comments welcome. Thank you.
JC
I FOUND THE ISSUE FOR MY CAR!!!!!!!!!!!!!!!

After several shops looked at my car and said no way hozay, I found my rattle.

The catalytic converter mounting welds are cracked. Tiny holes are in the metal housing too, like they chipped off. Upon warming up the car and smacking it with my wrist, which is VERY hot, the rattle was discovered. It only happened at 3k rpm but then changed to 1200 a few months in.

I also noticed that warming up my car, my flashlight was seeing a little cloudyness underneath the car. That means the housing is leaking a small amount of fumes. Also notice the actual bracket had a crack.

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Does this rattle sound kind of like a faint/mellow rod knock?
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