Engine ceased to climb through the revs for 2 sec. w/ gas pedal all the way in.....

[Zanardi 50]

Tonight while driving my NSX, I experienced an unexplainable phenomenon with the throttle input. I was waiting at the stop light at a fwy entrance ramp, ready to tackle the hard right-hand turn up ahead b4 leading to the fwy. The light turns green, I floored it on 1st gear, shifts near redline, then back on the throttle and abruptly floored it on 2nd gear, and for about a second the engine revs fine, but then suddenly the engine was NOT responding at all for a good 2 sec. or so(no rev climbing-like the engine suddenly froze up at ? rpm but not stalling), then the engine resumed climbing through the revs in normal fashion. All this time my right foot never eased up, still flooring the throttle pedal. I've never experienced something like this before. What seems to be the problem? Please explain. Thanks again.

 

[DutchBlackNsx]

TCS ?

 

[DaveJP]

From what you described...I would agree..Sounds like TCS activated.

 

[Zanardi 50]

Hm... that's strange. I had the TCS off when this occured, as I usually drive w/o it.

Any other possible explanations?

[This message has been edited by Zanardi 50 (edited 10 August 2002).]

 

[Zanardi 50]

Any other possible explanations?

 

[s2ktaxi]

Contiminated fuel?
Gas tank near empty?
Dirty fuel filter?
O2 sensor?

 

[Slingshot]

If TCS was off, sounds like the classic vapor lock.

 

[Zanardi 50]

Originally posted by s2ktaxi:
Contiminated fuel?
Gas tank near empty?
Dirty fuel filter?
O2 sensor?

1. Contaminated fuel- Nope. As far as I know, I made xtra precaution to tighten the fuel cap until it clicks x # of times, so that no H2O or any other foreign particles inadvertantly enter the gas tank.

2. Gas tank near empty- Nope. Tank was at least half full when this occured.

3. Dirty fuel filter- Not quite sure. I'll definitely have a looksie, but I doubt this might be the culprit, since I've used unocal 76 91 octne fuel on a consistent basis and had all scheduled maintenances done and everything else checked out by the dealer up to around 11,600 miles on the odo as of today......

4. O2 Sensor- Don't know how to check for this one. Please advise. Thanks.


[This message has been edited by Zanardi 50 (edited 11 August 2002).]

 

[Zanardi 50]

Originally posted by Slingshot:
If TCS was off, sounds like the classic vapor lock.

Since I'm new to this sports car hobby and somewhat mechanically-challenged when it comes to cars (but I'm learning more and more by the day), please explain to me this "vapor lock" problem. I will greatly appreciate your timeout taken to post your reply. Thanks in advance.

 

[Slingshot]

The best explanation I have heard is as follows:

Classic answer to very hot weather, low fuel pressure, not easily repeatable problem is VAPOR LOCK for most any gas vehicle.

Vapor lock is when the fuel gets so hot it turns from liquid to gas, like steam. When the fuel pump pressure is not enough to push the liquid through the lines, voila, vapor lock. It's usually a temporary condition that cures itself. Racers at drag strips often use their ice from the cooler on the manifold to avoid it from happening in the staging lanes. Summit sells coolcans to put ice in for the same purpose. Proper combustion depends on the proper air/fuel mix and hot air is thinner, and capable of holding less atomized fuel in suspension than cool air. Very hot air will hold little gas in suspension and the motor dies.
"andygears"

 

[Zanardi 50]

Andy, thank you very much for the reply!

I'll give my Z few hard run under same conditions as the last time I experienced this problem to see if I can repeat it.
I will have the dealer's technician look into this on my next scheduled oil change (coming soon) to see if it's something more than this, like problems with the fuel pump (?) or maybe even drive-by-wire system. Wish me luck.

P.S. I took the car out last night and logged in 90 miles, more or less. I ran the car easy for a good 90% of the time (mostly cruising through West LA surface streets, shifting at 3500rpm or less), and GUNNED it down the fwy. 10% of the time, shifting at 7000rpm or less. So far the problem did not remanifests itself yet. Hopefully it's just this vapor lock problem that you mentioned and nothing more.
But if vapor lock is what's causing this, then the intake air must be very hot, ie., outside air temperature is hot. But on that night the outside air was rather cool, like 55-65 degrees F. Hmm.... what else could it be?
Again, thanks for your input Andy!

You the man!



[This message has been edited by Zanardi 50 (edited 11 August 2002).]

 

[Carguy!]

One thing to check is the throttle by wire system, if for whatever reason the throttle position sensor gave a bad reading I would expect it to have these exact same symptoms.

Good Luck!

 

[Zanardi 50]

Originally posted by Carguy!:
One thing to check is the throttle by wire system, if for whatever reason the throttle position sensor gave a bad reading I would expect it to have these exact same symptoms.

Good Luck!

Hey Carguy, that's what I was thinking, too. But since I'm not really sure if DBW is the culprit, I'm going to bring the car to the dealership to have that looked at on my next oil change next week. Thanks to all who chipped in their time and wish me luck !

 

[Wadasan]

Z 50 have them check the TCS also. My 92 TCS had a mind of its own when I got it 2 years ago. The TCS would be off but managed to still engage randomly whenever it wanted too. Its one thing when you see that its not active, but having come on radomly can be frustrating. Had tech deactivate it.....

 

[Zanardi 50]

Thanks for the suggestion Wadasan. I hope that's not the case, because I'd like to have that option of turning the TCS on and off wherever I want to, whenever I want to. To disable it permanently is like cutting the NSX's toes off, if it has 'em. It's like a person can stand on his/her feet WITHOUT the use of toes (TCS off), but once he/she'e off balance (exceeded the car's cornering limit), WITHOUT toes he/she will find it dfficult to maintain equilibrium.

[This message has been edited by Zanardi 50 (edited 18 August 2002).]

 

[Zanardi 50]

I think I've found the answer here: http://www.nsxprime.com/ubb/Forum1/HTML/005985.html
Many thanks to all who left their marks here!

[This message has been edited by Zanardi 50 (edited 18 August 2002).]