Help....porblem with the car

[Auraraptor]

just got home after a drive in my nsx. while I was driving, the nsx suddenly changed its clutch feel. instead of the rpm going down very quickly when i pressed the clutch, it slowed a bit, not so much in the higher rpm, but in the lower rpm(1500-0) when it gets to the bottom, it goes below the regualar idle rpm and after a second pops back to normal idle. all the while i am pressing and holding the clutch. what happend? I burned the clutch on it once and had to pay 3300 and this seems a precuror to that bad nightmare. Please help, I am getting desperate now.

I took the car to a friend of mine who has a garage, and he says he(and so do I in fact) hear an air leak in the engine somewhere. has this ever happened to anyone else? If so where was it/where could it be?

Also how do you start the nsx from idle? i have a feeling im doing it wrong and thats wearing the clutch. I start by bring rpm to about 1500 and then slowly release the clutch, when see the rpm begin to fall, I hold the clutch there until i feel the 'click' meaning its engaged(you all know the 'click') then I immediaetly release the clutch out. is this wrong? how am I supposed to do it(without stalling or shuddering or pushing to 2000+rpm and burning clutch)

 

[Auraraptor]

oh yeah, it is a 97 six-speed nsx.

 

[ANYTIME]

Originally posted by Auraraptor:

Also how do you start the nsx from idle? i have a feeling im doing it wrong and thats wearing the clutch. I start by bring rpm to about 1500 and then slowly release the clutch, when see the rpm begin to fall, I hold the clutch there until i feel the 'click' meaning its engaged(you all know the 'click') then I immediaetly release the clutch out. is this wrong? how am I supposed to do it(without stalling or shuddering or pushing to 2000+rpm and burning clutch)

The easiest way to minimize the shudder is to blip the throttle just before engaging the clutch so that the clutch starts to engage as the engine speed is falling. This will get the car rolling as the engine speed is dropping. Fully engage the clutch at between 1100 and 1500, then apply throttle, or have the clutch almost fully engaged before applying throttle.
John

 

[sjs]

Your RPM symptoms are probably vacuum related. A big vacuum leak will cause what you describe. Perhaps a hose has come off or leaks, which would also produce the sound you hear. Also check the disk shaped device at the throttle body towards the front. It is a vacuum actuated dash pot and may be bad. A leak large enough to cause your problem should be simple to isolate with careful listening. Of course it could be something else, hard to tell from here, but I’d look at all the smaller hoses first.

Vacuum leak or not, nothing about your symptoms suggest a precursor to another clutch failure, but your driving style probably does. (no offense, it's a common problem) There is no way to tell how bad it is without riding with you, but your description suggests that you are not doing it correctly (for any car). Engaging the clutch (letting it out is know as "engaging") should be a single smooth action that lasts barely a second even for a gentle take off. As noted by Anytime above, the simplest way is to blip the throttle slightly then catch it on the way down, letting the clutch out and at the same time feeding the throttle back in. Practice the basic rhythm without the car running, or even sitting in the house. The right foot flicks the throttle, then the left foot smoothly releases the clutch pedal as the right foot starts depressing the throttle again. For a gentle take off the left foot moves much further than the right, but they move at the same time with the left just a fraction of a second ahead. Of course, the best thing to do is ride with someone with lots of experience and watch them carefully then practice while they watch you. If you can do it in a cheaper beater, so much the better. There is nothing particularly remarkable or different about the NSX once you learn proper technique, especially the later models.

Good luck!

 

[Auraraptor]

thnks for the help, one question, bliping is what exacly?

 

[sjs]

Originally posted by Auraraptor:
thnks for the help, one question, bliping is what exacly?

Ah, sorry. It refers to a very brief tap on the accelerator to "blip" the RPM up to 2000 or 2500. (I never really watch the tach during a blip so I can't swear to the typical RPM I get) Pretty much tap it as fast as your foot will pivot on your heal down and back up but only hard enough to move it a small amount rapidly to achieve the rise in RPM. Again, no magic here but it's hard to describe the exact amount you press the pedal or how fast, but once you hear it you can reproduce it.

As the RPM falls back down is when you start letting out the clutch, smoothly but decisively. Timing of all the little pieces is what makes the difference, so it takes practice.


[This message has been edited by sjs (edited 18 August 2002).]

 

[huckster]

if it makes you feel any better, ive driven tons of manuel clutch vehicles--from 3ton farm trucks to pickups to import cars as well as motorcyles. i think the nsx engine/drivetrain is one of the more difficult i've driven. (in terms of a perfect no stress launch). i've gotten the 'nsx shudder' on several occasions.

 

[mikec]

I'm pretty good at launching my car with a minimum of clutch stress, but sometimes I get the engine RPM's a bit wrong because its so quiet. I'm thinking that a louder exhaust may help by letting me hear the engine rev. What do you think?

I'm trying to justify getting an aftermarket exhause every way I can

------------------
keep the shiny side up
MikeC 01 #46

 

[Auraraptor]

I just talked to my buddy who owns a garage again. He says that the leaking sound disappears when the the engine is cold. So then is that normal?

As for the disk vaccum thing on the t. body, what is the part # and how do I tell if its broken.

We heard the 'leak' when the engine was warm, but could pin point its location no matter how hard we tried, even though it was really loud.

 

[salontools]

Get the service manual from Heim (sp?). It's on this site, but it's easier if you have the book.
In the emissions section is a troubleshooting guide for your type of problem.
Use a 24" length of garden hose or get a mechanic's stethoscope to help find the leak. Please note that alot of vacuum hoses run into a black emissions control box (can't remember the name of it) on the firewall behind the air filter box.
Bob
'94 All green / tan

 

[Auraraptor]

Originally posted by sjs:


As the RPM falls back down is when you start letting out the clutch, smoothly but decisively. Timing of all the little pieces is what makes the difference, so it takes practice.

[This message has been edited by sjs (edited 18 August 2002).]

Do you release quickly the clutch (less than a half second) or longer ?

 

[kpond]

I too believe your symptoms are characteristic of a vacuum leak - especially with a large sucking sound when warm!

Sjs was right on to suspect the Dashpot. It's job is to let the rpm's gently and your description is that they fall abruptly and dip below normal momentarily.

I've never really heard of one failing but perhaps yours has. I think you can test it by temporarily putting a short vacuum line to it and sucking on it. You shouldn't be able to. If you can, the diaphragm is likely ruptured. However, a large vacuum leak somewhere else can also cause your symptoms and may be more likely of a problem.

An old, and likely very dangerous, mechanics trick is to take an unlit propane torch with the gas slightly on and probe the tip around in areas where you hear the sound from. If you detect a momentary rise in RPM, you've found your vacuum leak.

Like I said, this isn't the smartest test - but one that I have used effectively.

Geez, these message are harder and harder to type with only one hand and no eyebrows...

 

[Auraraptor]

"If you have the engine rpms as low as possible and give it only the amount of throttle necessary to launch, then you can get he car rolling with little wear on the clutch. Soon as the car is rolling, you can let the clutch out the rest of the way. This takes a little practice, but is something we should all do."
this is from http://www.nsxhelp.com/faq/clutch.htm

it sounds like what I am doing....
comments concerns? I really want my clutch to last...

 

[sjs]

Originally posted by kpond:
... Geez, these message are harder and harder to type with only one hand and no eyebrows...

LOL!

We used to find vacuum leaks by spraying "starting fluid" (mostly ether) or carburetor cleaner at suspect areas with lots of vacuum lines, around intake gaskets, etc. Never tried the propane thing, but they are al similarly risky.