Abnormal throttle noise

[RunHachi]

Hi Guys,

Hope some of you can shed some light... Currently experiencing the following issue.

No engine/transmission mods.

There seems to be a noticeable short hiss sound when the throttle is quickly pressed/blipped during:

1) Clutch depressed - in gear or in neutral.
2) When driving in gear, any gear, (not touching the clutch at all) and just giving the throttle a quick stab.

This issue first occurred during a long drive on a warm/hot day.

The only way I can describe the sound is like a louder than normal induction sucking noise when blipping the throttle. Just a quick hiss (like a BOV). Its mainly right when the throttle is pressed.

The other thing is, its an intermediate problem. Happens here and there. Does not matter how I drive it, but can seem to replicate it more on warm/hotter days. (I know normally there is an induction noise when blipping the throttle, but this is way louder than normal.)

There is no other abnormal noise during start up, idle. car sounds fine when idling for a long period. No knocking, popping and nothing out of the ordinary. I have blocked off the sound tube and tested, still happens. I have done some research, thinking it could be the pilot bearing, but could be ruled out cause it also happens when in gear driving?

The sound does sound like its coming from behind the pedals firewall. That's why I thought it was the sound tube. But removing that didn't help.
Logged it with Toyota, they checked the car and no leaks, and could not replicate, typical...

No performance drops. car drives fine beside that hissing sound here and there when shifting or giving the throttle a stab. Obviously something not right, but can't pin point. When researching, some members seem to have this issue, but can't seem to find out what the problem is.

[zkv476]

It gets even more pronounced with aftermarket intakes, I hear it virtually 100% of the time. I feel like it's normal, it's just the throttle opening quickly and the air rushing past the plate. My brother's accord with an intake does the same thing too. No performance impact. That's probably why there's resonators and little things all over the intake system.

[Ozzman]

Same thing happens to my car, only with the clutch depressed and RPM's rising past roughly 3500 rpm's. First time I heard it, it sounded like a faint honking noise, not unlike the horn, just quieter. I've plugged the resonator, no change. At first I wanted to say it was intake noise, but the sound only happens with the clutch depressed. It makes me want to blame the throwout bearing, pilot bearing, or pressure plate, but I haven't really investigated and will take to the dealer when I get annoyed enough or the sound gets worse or starts changing. Thinking about it some more I could rule out the pilot bearing by seeing if there is a change in the occurrence of the noise of being in gear or in neutral, the changing being pitch, tone, or RPM at which it occurs.

[RunHachi]

I had this car for over a year and have not heard this sound till recently, especially when pressing the throttle after a gear shift or just stabbing the throttle quickly, which I never noticed it doing before.

It wouldn't bother me as much, if it did it all the time. Just want to find out what the cause is...

Anyway I have reported this to my dealer. They told me to monitor it and bring it in if gets worst.


Cheers