Rev hang

[S2KFTWkthx]

Alright you guys, this is the second time ive turned straight to Xviper to help me solve a problem...

Ok, so i was coming to a stop at a light, downshifted, revmatched, and when rpms were ~2k, i let off the clutch. well, the clutch was in for 2 or 3 seconds before the rpms dropped to normal idleing speed. I know many people say to let rpms dip to idle and press the clutch to help the ecu with idling and whatnot. could that be it? the ecu? or something else?

BTW it did do this three times within the timespan of about 15 minutes. I thought it might be the clutch so i did the 4k rpm test on an incline but it didnt seem to slip

THX!
Dan

[repiv]

"Rev hang" is another one of those peculiarities of an ECU controlled fuel injected car. This is the opposite of the dipping idle when coming to a stop where the rpm goes so low, the engine shakes and almost stalls. Ordinarily, on deceleration in gear, the ECU turns off the injectors. However, depending upon just how long after the rev match (throttle blip) that you actually decelerated before pushing the clutch in, the ECU may not have been in the "frame of mind" to totally shut down the injectors and may continue to run the injectors as if it were seeing the last thing that was done to the throttle (throttle position).
As we've seen on these S2000 forums, sometimes we get complaints of dipping idle to near stall and sometimes (although much fewer) we get reports of hanging revs. I've seen this myself on occasion when I've been at steady state cruising in the mid rpm range and just pushed the clutch in and let go of the gas pedal. If the conditions are right the revs will hang momentarily before they come down to normal idle while just coasting at speed. At other times when I do this (particularly when it's very hot under the hood), the revs will almost die. In this case, high intake temps contributes greatly to it.
I don't think rev hang is a problem as such and is a far better oddity than stumbling idle.

[S2KFTWkthx]

Thank you for all your help :bow:

[User Omega]

Could be throwout bearing going out.

[hamrhd]

I'd throw out my bearing before I'd go out with it, um, oh nevermind.

[S2KFTWkthx]

yknow, i really hope that didnt take long to think up...

:rofl: :thumbup: