Max Petrovskey

Hello people!

Recently bought an s2000 and it works great except noticed intermittent noise that the engine makes. It's only at idle and it happens 70% of the time when engine is warm. Also starts vibrating a bit when it makes this noise. Other times it doesn't vibrate and do any of the noise. AC is always off. Pulleys seem to be good - no play. At the moment when the video is shot radiator fan is off.

Here is a link to the video
Any Ideas?

Soviet

Just to be clear, are you referring to the loud humming noise throughout the video?

Max Petrovskey

Yes thats it ... humming noise

Tonygeez

Its the IAC system on these cars. If you don't have the airbox cover on or you have an aftermarket intake, they make this noise. Its completely normal. I bet if you find an airbox lid, the sound will almost completely disappear. These IAC valves are built into the intake in such a way they create a hum or certain harmonic frequency that resinates with specific intakes (oem without a lid). Its strange.. but again, its normal. As far as it causing a vibration, that must be coincidental with something else. I'd continue to research the vibration and ensure your idle is set properly, or verify there are no other problems.

Max Petrovskey

Good to hear about noise, was worried a bit... shaking is pretty bad though... I did clean out the IAC valve and it didn't change anything.

Tonygeez

If you have any more details about the shaking, that would help. ( i.e.when, temperatures, how violent, RPM, speed etc.) I didnt notice any shaking in the video... Otherwise, If its idle, make sure the MAF is clean as that can cause a rough idle. Also ensure you dont have a misfire.. sometimes misfires can be inconsistent.. especially if you have old spark plugs or coils. These engines are really smooth when running right, just ensure all you basic maintenance is up to par... Once youre sure your maintenance items are good. Then look at adjusting things like idle (should be at 900 when warm). Generally speaking though.. good maintenance will fix just about anything thats not broken lol

Max Petrovskey

I guess I need to clean the MAF sensor next. I've done all liquids on my Honda so will do any maintenance I need to make sure it's smooth.

Recorded a video while it was shaking... Hope it helps...

Tonygeez

oh ok.. wow.. that is a really strange vibration/shaking.. not a low frequency vibration like a misfire would be. Honestly.. Providing there is nothing wrong with your driveline (press and release the clutch to see if there is a difference). My last idea would be motor or transmission mounts. your car seems to be running smooth, just vibrates like the massage chair at the mall lol. Hopefully somebody else can chime in, but my last idea is worn motor or trans mounts. Id give all of those mounts an inspection-and ensure the rubber bushes are in tact and yeah... hopefully somebody else has had this problem. Best of luck!

Max Petrovskey

Thank you!

Hooked up my obd reader and no codes but what i've noticed is the vibration appears when car warmes up and shows about 800 rpm. I've heard that it needs to be at 900... How can I bring it back up? Do you think its the reason?

Will check the mounts tomorrow when I have more time.

Tonygeez

As you reach the end of my limited expertise, I would expect that 100rpm difference would not create such a harsh vibration. Again, I would inspect all motor and transmission mounts to ensure they are in good condition before adjusting the idle. Next I would attempt to let the ECU relearn the idle by performing the idle relearn procedure (look it up on these forums. Really simple process). There is no manual idle adjustment like on some other mechanical throttles. The only way to reset the idle is to let the ECU relearn it. Beyond this.. providing other maintenance is performed (ie MAF cleaned and IAC cleaned) and you have verified no misfires. I dont know what to add lol.

If anybody else has experienced this or has any other ideas, your input is greatly appreciated!. Cheers and again, best of luck to you!