trep

I'd say that it really feels like it's coming from the transmission, it feels close to the shifter. I'm gonna try what you say and come back with results heh

xviper

When the engine struggles to come back from a dipping idle, it can tend to shake. This shaking can make certain parts vibration and rock. Your tranny mount is one of them but with only 37K on the odo, I can't see them coming loose yet unless a previous owner did a clutch job and didn't torque the mount back up properly. It could also be that the shaking is causing some shifter rocking. These would point towards your feeling that it's coming from the tranny. However, the engine shaking can also cause the motor mounts to move. The shaking is a manifestation of the engine going into knock (aka pre-ignition, dieseling, pinging) when the rpm goes too low.

trep

Thanks for further explaining. I've tried clutch pressed in neutral, clutch depressed in neutral, clutch pressed in first gear and it did it in all scenario. Also, the sound stays there for a bit when the idle goes back to normal and fade away at some point. If I press the gaz to get going, it disappears instantly. I can also hear the same sound when stopping the engine or stalling (happened a couple of times hehe) or if I come close to stall. I have all receipts from the original owner (i'm the second owner) and the clutch was never replaced. I don't think the previous owner tried to hide anything but you never know. I think the best way to find the source would be to lift it and make it do the sound but I'll have to see with the mechanic for this. Anyway, thanks for your inputs !

4forall

xviper i agree with you, there is no reason to blip the throttle and the car is struggling to maintain idle b/c of this. And as for the person saying the car idles when its cooler, i believe he ment the ambient temp outside.

I have noticed myself in the past two days its been around 10 deg cooler and the humidity has been substantially lower and my car idles like a dream as well as increased throttle response. I usually leave the car in gear as long as possible when coming to a stop on hot days and that keeps it from dipping most of the time. But just the fact that its a complete non issue when its cooler and not humid makes me think somthing is wrong.

Now i understand this is totally a creature comfort and being nit picky but when your car is running smooth it just makes ya happy lol. I am going to do an idle relearn soon and try to police myself for the first few weeks on my driving habits so that it learns the correct idle.

As far as the noise, i get that all the time, once the rpms drop so low the motor starts rocking and just shudders. This causes all sorts of things to vibrate and make noise. But again all info is based upon my personal experience over the past two years with the s2k as well as multiple other honda motors whos idles are based upon map/iacv systems. which in my opinion dont age well at all.

Saki GT

In general, whe temps change from hot to cold or vice versa, the ECU needs to adjust for the change in atmospheric conditions. Rough idle is common in modern cars when the temps swing wildly, but it should be temporary as the ECU learns and adjusts.

The issue is, is your car idling smoothly at all?

trep

Well, I tend to think that the vibration is normal. I used to have a '99 Si and my mom had a '00 DX hatchback. The engine vibration(s) coming from my car was much less than my mom's car even tho it was revving much higher. Maybe it was something to do with the engine mounts, the sway bar or a mix of everything, I don't know. I'm still getting used to the S2000 behavior regarding idle, starting, enaging, clutching, shifting etc.

In general, the car idles fine. It will play in a range of 100rpm when i come at a red light or a stop. Only time it acts a bit weird is let's say I take it, go to a shop for 20mins, when i start it again, the idle might play in the range of 300rpm, back and forth quite fast, it's very easy to notice and audible. I'm probably going to do the idle relearn procedure to see how it runs after that.

trep

Well, I started noticing the vibration when i'm depressing the clutch. Fully pressed, no vibration, fully depressed no vibration. It only does it when i'm depressing it, like at the halwfay mark. If I keep it pressed halfway, it only vibrates for a second and same thing when i'm depressing it, vibration lasts a second or so...

Anyway car runs fine, but if it's something I can fix, i'd be more than happy !