neoteny

So if I accelerate flat out w/ my '04 Accord 3.0L V6 6MT in 2nd or 3rd gear, there's this chirping noise coming out of the engine (or at least from under the hood) roughly from 5,000 to 6,500 RPM. It doesn't happen (or at least I don't hear it) if I do the acceleration in 1st gear.

I tought that it might be high RPM knocking due to regular (87 octane) gas, so I've filled her up w/ 94 octane gas. No luck w/ that: the chirping sound still comes on.

Unfortunately I can't determine if it comes from the engine or something attached to the engine.

Any ideas?

94vtecmn

Could be almost anything that rattles or vibrates at a certain RPM. Can you try to replicate it while stopped revving the motor? I have a little sound that occurs about 4k RPM, just haven't had time to diagnose it. My guess is a heat shield or something, not going to worry about it since it only happens at that certain RPM.

neoteny

Nope; when the engine isn't under load, I can't rev it over ~5,500; the ECU limits whatever it limits (ignition, injection or both) at that RPM.

Yes, I understand that anything attached to the engine can be the source of the chirping noise (when the engine's RPM is in the range of the resonant frequency of the item). It's just that I get paranoid and start to envision a broken piston ring.

94vtecmn

The motor won't last long with a broken piston ring revving past 5k. I wouldn't worry about it.

neoteny

It looks like a broken front engine mount is the cause of the noise; I'll know for sure once they've replaced the mount (and the noise goes away, hopefully).

MikeM

Since you're getting a new clutch, have them replace the front mount at the same time as the clutch, the labor should overlap saving you some cash.

neoteny

Indeed that's what happening.

Jlmejia316

If you're still having a chirping noise issue, try removing the belt and take a drive in an attempt to duplicate it. If the noise is gone than you know it is accessory drive belt related. If it remains, then there may be an issue with the timing drive components.

neoteny

Thx, I'll keep this in mind.

VeeSykkz

My clutch FORK CHIRPS! make sure thats not an issue, its a grand to fix.

neoteny

Well, they just did a full clucth/3rd gear job on my car. Those things work as expected -- although they cost me dearly.

Unfortunately the chirping noise is still there -- the engine mount change did not fix _this_ issue.

I'll try to get a (cold) valve adjustment done on the engine (which can get expensive -- apparently "some Honda V6 engines require 4.6 hours of work for valve adjustment"). At the same time I want the 6 new spark plugs I bought off Amazon.ca put in (the front 3 are trivial, but apparently the rear 3 aren't so by any measure). If they're there, they ought to be able to do a compression measurement for less. That ought to be able to cover any source of chirping noise coming from the (upper part of the) engine, I think.

I'll report back when there's any development on this issue.

94vtecmn

The rear plugs aren't as bad as you think, there's plenty of room in there to do them yourself. But yeah, sounds like your willing to throw a few grand at this thing, might as well keep spending!

neoteny

I'm not a mazochist, but this car was due for a general tune-up at 105 K miles (~170 K km) -- instead it was apparently driven hard and not maintained at all in the last while (now it has 200K km on it). I bought it relatively cheap, and I was expecting expenses. Of course if I would have another car (to go to work with) and a (rented) garage where I could hack at her, I could get some things done myself -- but that isn't the case. So I order the obviously identifiable parts off the Net ... and I'm happy if I can find local shops which are willing to install parts which aren't bought by them. Because some flatly refuse -- at least to me -- to do so.

(In the transmission shop they removed the battery connectors -- which made my Honda factory radio lock itself. I had no radio code, and the shop couldn't get it to cough up the code. So I went to my local Honda dealership, and one of their service guys did his magic -- got the code for me and even reset the radio. For free, with a smile. I liked that very much.)

neoteny

Finally I did the spark plugs myself. There's just enough room on the rear. It took me 50 minutes to change the rear three and 12 minutes to do the front three.

And it is a good thing that I did it myself: in the process I realized that the two bolts on the top of the housing of the power streering pump were both loose. The power steering was making loud noises before (when warmed up); now those noises are considerably quieter.

Unfortunately the chirping noise on hard acceleration is still there. The quest continues ...

Almighty-Si

Try removing the heat shield on the intermediate shaft.

neoteny

Thx for the idea; I'll look into it in due course.