I just got an 04 S2000 about a week ago. I've had some manual cars in the past. My car has about 600 miles on it so I doubt its anything. My question is, when i press in the clutch the RPM stays where it is for a good sec and doesnt drop like all the manual cars i've owned. I know how to shift so I know its not me. Even before I shift to another gear, I'll release the gas all the way and then press the clutch and the RPM will hover where it was before I pressed the clutch for a sec before it drops. Is this part of the clutch delay? I havent really driven the car hard yet to understand what this delay does but is this a feature of it?

 

You are correct. CDV is designed to help to perform lazy shift smoothly but it hinders quick shifts.
BMWs have this too and people in that camp just remove the valve to get rid of this annoying feature.

 

No. The CDV only affects clutch engagement. Disengagement is not affected by this valve. Your rpm "hang" has nothing to do with the clutch delay valve. It may be normal (it doesn't do it in my MY2000 car) but it could be something to do with the throttle position sensor or the MAP sensor or the Idle Air Control. It doesn't sound like something to worry about.

 

According to your description, it sounds like a different phenomenon where you press the clutch (DISENGAGE engine from driveline) engine speed stays constant for a brief moment before starting to drop. In contrast, CDV acts up when you release the clutch (ENGAGE engine to driveline), not when you press on the clutch. Can you confirm which one is it? I mean all this happening BEFORE (meaning slow engine response) or AFTER (meaning slow clutch response) you release the clutch? If BEFORE, this problem is common to many cars especially big sedans with manual transmission where the flywheel is heavy and/or the ECU is programmed to slowly shut down fuel for smoother operation. However, this should NOT happen to the S2000 because the car has a very light flywheel and has a fast ECU from the factory. The S2000 would be the last car to see this problem. If this indeed happens to your car, then it's not normal.

 

Thats what I figured. I drove an 02 and dont remember it doing that. I'm not worried about it. I just thought I'd ask. I guess i'll have to drive another AP2 to see if it does the same thing. Oh well. Not too worried. Thanks for the responses.

 

Race Miata,

For example, lets say i'm in 3rd gear and my RPM is at 4k. When I press down on the clutch to shift to 4th, this is where the RPM will stay at 4k for just a sec then will drop if you take your time putting it into 4th. I just didnt know if this was normal or not since my other manual cars I didnt experience this.

 

I'd check both the throttle cable and throttle body to see if the mechanism is "hanging up" somewhere.

 

Like others have said, check throttle cable and throttle body for stickiness. Also check cruise control cable. Trace for possible vacuum leak. Anything that can cause too high "natural" idle can introduce a delay for the IAC to correct.

 

Completely normal for an MY04 car. At least, normal based on a sample of two - mine did the exact same thing. Really bugged me until I started getting used to it.