Revs DURING shifting..

[SarcasticaLy]

Hopefully I can explain this correctly....

'96 NSX-T.

Ever since Ive had the car (last June), when I shift Im noticing that the RPMs jump a little bit as if Im blipping the throttle to UPshift, its pretty weird. Ive asked a few local guys but they have no clue what Im talking about. Im not sure of the history of the flywheel. From what the previous owner told me, its still on the original clutch/flywheel. (93k miles right now).

 

[toomanymodz]

So, you mean the RPMs climb slightly when you press in the clutch to shift, rather than dropping RPMs like it should when you press the clutch and lift on the throttle?

 

[SarcasticaLy]

Exactly. I let go of the gas and simultaneously press in the clutch and the RPMS climb slightly. Thoughts?

 

[JD Cross]

Something amiss with the drive by wire?
Slightly sticking gas pedal?

 

[Dr. JL]

Mine does the same. Love it.

 

[SarcasticaLy]

Doesn't really bother me too much, just wanting an explanation. I should take a look at the DBW system.

 

[stuntman]

Your timing a bit off (still on throttle a tiny bit as you're dipping into the clutch)?

 

[SarcasticaLy]

Your timing a bit off (still on throttle a tiny bit as you're dipping into the clutch)?

Lol, no its not that. Id like to think I know how to drive stick. Ive tried doing the whole shifting sequence a bit slower as to eliminate any error on my part and it still does it. Not as much as when doing it normal speed but still does it nonetheless.

 

[type-j]

I think that's the symptom of a clutch on its way out

 

[SarcasticaLy]

Hmm...I have to disagree. Seems like the complete opposite as the typical way of knowing a clutch is going would be slippage. If the clutch releases then the revs shouldn't climb. If the clutch is engaged, it would control the RPMs, not raise them.

 

[dquarasr2]

A few years ago I bought one of the first Mazda6 sedans in the country, 2003 model. Everyone who drove it experienced throttle overrun and over-rev'd the motor on redline upshifts. It was a minor compromise in the DBW system as it seemed that all Mazda6 of that vintage had this problem. It was annoying but I got used to it.

I verified that it was the "slow" DBW, and you can do the same. Just monitor the engine reaction while at rest. You can gently rev the engine and see how long it takes to react to your inputs. Same thing on releasing the throttle, see if RPM's drop right away or if it delays a 1/4 or 1/2 second.

Although you sorta indicate you are comfortable with the car, you are aware that clutch engagement is rather high on most NSX, which could influence your timing, but I based on what you had said I don't think that's your issue.

Best of luck figuring it out.

 

[SarcasticaLy]

Yeah I'm aware of the engagement point. Not a factor. I don't think I'll be putting too much effort into solving the issue. Maybe a quick skin through the manual. Thanks for all the input guys.

 

[toomanymodz]

Mine does it every now and then, but not all the time. My 2011 Jeep does it when first started cold. I wouldn't worry about it.

 

[Big_D]

My wifes 350Z does the same thing...drives me crazy. I am not a fan of drive-by-wire...for that reason.

 

[CDX_NSX]

Vacuum leak or sticking/dirty throttle body? If I remember correctly, I may have had the same problem on my Legend which turned out to be a vacuum line that had been gnawed away by a squirrel.

 

[ralph cerbone]

normal ,try this, before you shift, take foot off gas pedal ,then depress clutch , this will cancel rpm increase .

 

[SarcasticaLy]

Well, interesting enough, maybe there IS something to type-j was saying. When Acura called me about my door latch, they told me the NSX tech was looking over the car and noticed that the clutch engagement is really high which is indicative of a clutch on its way out. Crazy! In THEORY, the way I understand it, it shouldn't coincide with the clutch. Anyway, it did cross my mind to replace it soon. Well, whenever I get around to replacing it, I will give you guys an update and see if there's any changes.

Oh, and ralph, Ive tried that. Same thing, RPMs jump.

 

[type-j]

I just remember when my clutch was on its way out the revs would jump up every time I would engage it.

 

[SarcasticaLy]

Hmm..ENgage or DISengage? Mine is at disengagement. Either way, we shall see what happens.

 

[type-j]

Sorry I meant to write disengage.

 

[Big_D]

For the NSX it is normal for the clutch engagement to be high.

To determine if the clutch is on its way out you want to put it in 3rd or 4th gear and then accellerate from a low rpm range and see if there is any slippage under load.

 

[ralph cerbone]

Just tried my car (97),performed exactly as i posted. Shifting normally (3500) rpm's would jump about 200 rpm. If i lifted throttle completely (foot off) and then disengaged clutch no rpm increase .I never paid attention to this till I read a post here were someone explained how to cancel this , I searched but couldn't find the post. In late 80's I attended a BMW Tech class on their new DBW system (EML is what they called it) ,a BMW tech reported a slighted increase in rpms between shifts , the instructors explanation was its there to clear any H/C on throttle release.