SuperJ, thanks for the update. I'm sorry the tightened plug didn't fix the problem, but glad you caught it before it popped out of the cylinder head and that the car's running well with the new plugs.

If the tightened clamp helps please let us know. I asked the shade-tree mechanic in the town where I spend my summers to look for a loose heat shield but he couldn't find anything. He might have missed a clamp though.

One other possible clue: I had the drive belt replaced a month or so before the noise started. Perhaps the noise has to do with that? It sure doesn't sound like a drive-belt issue though.

 

I drove it with the tightened clamp this morning. The noise seems to be essentially gone!

To recap... I changed the plugs (Denso IK20TT) and drove it and noticed the noise was still evident.

I then fixed the intake hose clamp, and think it may have been most of the problem. There is still a quieter exhaust ticking under load (like a very minor exhaust leak). But this is different and not really rpm dependent like the first noise. Note the clamp was just loosely hanging on the throttle body inlet side. I had to tighten it by more than 0.5" to get it snug up the intake tubing to the throttle body. (stock intake).

I wonder if the pulses in the intake cause intermittent leaks around 2200rpm because of a harmonic resonance in the intake the makes the pulses stronger at that RPM. It would make sense that Honda might tune their OEM intake to somewhere around that frequency to give a little better bottom end torque.

I not going to claim definitive success until I driven it a week under different temperature conditions and distances. This morning was a cold morning and a shorter drive so it may have masked the problem.

I noticed another noise source while getting a coffee in drivethru this morning. The motor is much quieter if I clutch in. If I idle with my foot OFF the clutch there is kind of a constant "shhing" sound. But it goes away if a press the clutch. It is evident if a I rev with or without the clutch in too. Does anyone else notice this?

I will report back after a couple days to confirm my fix.


NOTE: It's hard to check the heat shields and intake clamps etc without removing the upper cowling and wiper assembly. It's not that bad to remove and really makes trouble shooting easier.

 

Thanks for the update, SuperJ. That would be a huge help to many of us if you've found the problem. It's worrisome having your engine make a noise like this.

Please confirm that the noise is still gone, if indeed it is. Also, any advice on whether the clamp can be tightened without removing cowling, etc. would be appreciated. If I can do it myself I will, but, living in the city, I have no place to do serious work on the car, and no tools to speak of either. If I can't do it myself I'll see if I can get the dealership that changed my plugs to do it for me. Perhaps the loose clamp has something to do with work they did when they changed the plugs?

 

I still can't say definitely if the noise is gone but it definitely reduced and the car runs better.
You might be able to access the clamp if the screw head is pointed towards the front of the car. (Mine would be.) It's on the right hand side of the throttle body at the top (if your standing looking at the engine). It's a philips head screw.

 

Today I had a friend who’s a good mechanic listen to the engine from a cold start to fully warm while I held the revs at 2200. He used a tube from my vacuum cleaner as a stethoscope. The noise was definitely there, and gradually diminished as the engine warmed up, and was essentially gone by about 7 minutes of operation @ 2200 rpm starting at about 55 degrees. He said the sound is coming from inside the engine over on the left side by the oil-filler cap. He’s pretty certain it’s valve or lifter noise, something especially likely given that the noise fades as the engine warms. So, when I take the car in for its state inspection in February I’ll ask them to adjust the valves as well and see if that takes care of it (the last adjustment was at 60k with the LMS recall, and the car now has almost 140k on it). I’ll post again if it does.

 

The car runs great with the new plugs (noticeable more torque between 3000-5000rpm). But the sounds comes back.

I'm due for the valve adjustment (about 105,000miles/170,000km), will have a peak at the heat shields at the same time.

 

Well it wasn't the valves or the heat shields. It was bearings on the input shaft of the transmission. Just got it fixed and it's quiet now.

 

This is bad news if it's transmission related....

 

Yep, it's expensive. The give away for me was I noticed it sounded different with the clutch in while idling in neutral. Then I popped the hood and could tell the transmission was a little noisy. It totally fixed the problem for me though. Bummed cause the car obviously was this way when I bought it but I downplayed the noise.

It was an expensive day...
bearings where $400 (did all them)
Clutch $320
Labour $850ish
Fly wheel resurface $75
Canadian prices at a local transmission shop.

 

I have a 2012 Honda Fit with 20 some thousand miles on it. I too hear a clattering sound. It is noticeable when I am lightly on the gas or letting off the gas, while travelling, usually on second gear, and near 2000 rpm's. I've been wondering, valve clatter or something else? The frequency of the clatter is maybe 20Hz .. hard to tell. Does the fit need valve adjustments at 20K? I would think not. Under more powerful acceleration, I do not hear it, though possibly because the sound is drowned out.

 

Yep, you've pretty well described the symptoms and when it happens. Sounds like you're hearing the same thing I am.
No, these cars should NOT need valve adjustments anywhere close to this few miles.

 

how did you get that diagnosed, the bearings on the input shaft of the transmission? Did you find it yourself?

 

For two years I've had an engine rattle while accelerating at lower rpm. Finally found the cause while pulling the tranmission... a loose passenger-side drive shaft heat shield. The heat shield has heat-isolation bushings that had become sloppy. A little pinching of the three bushings quieted things nicely!

I too had the noisy input shaft bearings in my transmission. At idle in neutral, push the clutch in, all is quiet, let out the clutch and hear the whirring noise of worn bearings

 

I have a 2011 Sport AT with 62K miles and over the last 3 yrs the valve train chatter while under mild acceleration too. The problem is always more noticeable as it gets colder here in Pennsylvania (10 deg F this morning). Each year it has gotten a little worse.

Why would valve clearance increase when normal wear makes it tighter? Maybe there is carbon build up around the valve sets / stem that is preventing full closure, and therefore, more end gap and more noise. You got me why it is more noticeable when it's colder.

My 2 cents

 

I have same problem, any solution yet?

 

This old thread seems to be all over the place in terms of cause and solutions. From a loose clamp to a valve adjustment to a heat shield noise or something by the oil cap until the engine heats up.
The later one almost sounds like a vacuum leak because of a bad oil cap.