Engine Trouble

[Jackson86]

Hey Everyone,
I just bought a 91 NSX and took it for my first drive a couple hours ago, I was blown away. I have been a Porsche 911 fan my whole life and was not sure about trying something new, but this is a really great performing car. The car does need a little TLC here and there, but all-in-all its in great shape. The windows are sluggish and there are a few blemishes that I am going to fix but there was one thing that is bothering me, the engine shut of randomly between 2nd and 3rd gear under hard acceleration.

When I depressed the clutch pedal the engine didn't simply return to idle, but died completely. The engine cranked back up immediately with the key and did not shut down unexpectedly again while I was running the car. This seems like some kind of an idle switch or tps problem to me from my experience with my other cars, but I figured I'd see what the experts have to say. Any ideas out there?

 

[JD Cross]

One thing to consider is the ignition switch which wears out over time and can cause hard starting or unexpected shutdowns.
Fortunately it's a low cost fix and worth doing even if it seems to be working fine.
I believe it's item 11 on this page.
http://www.acuraoemparts.com/delray...COMBINATION+SWITCH+(1)&ListAll=All&vinsrch=no.

 

[Old Guy]

Its not the TPS. Engines that use MAP sensors can usually operate (maybe not very well) with the TPS completely disconnected.

I believe the NSX, like a lot of other engines, shuts fuel off when the throttle is closed and then restarts injecting when the RPM drops close to idle or when the throttle is opened again. I can't remember the specifics about the NSX; but, I seem to recall that the throttle switch has to go completely closed or close to completely closed for this momentary shut down to take place. When this occurs, the engine should not die completely as fuel injection should start as it approaches idle speed. If this was your problem, I think that it would occur all the time. Since that is not the case, I think your problem lies elsewhere.

As JD suggests, check the ignition switch. with the engine running and in neutral, try wiggling the key a little bit (definitely not so much that you engage the starter) and see if the engine has a momentary hesitation or dies.

 

[Jackson86]

Thanks a lot, the car had sat for a while and it hasn't happened again. I have jiggled the key and not noticed any change. I think this was a case of getting the cobwebs blown out. The other thing I have noticed though, is that the engine takes a lot longer to start when it is warm than when I first crank it in the morning. It's nothing too crazy, but it turns over for a few seconds before it kicks - is this normal?

 

[Honcho]

Thanks a lot, the car had sat for a while and it hasn't happened again. I have jiggled the key and not noticed any change. I think this was a case of getting the cobwebs blown out. The other thing I have noticed though, is that the engine takes a lot longer to start when it is warm than when I first crank it in the morning. It's nothing too crazy, but it turns over for a few seconds before it kicks - is this normal?

Check your battery and starter. A warm engine generates more cylinder pressure because the rings expand to create a better seal. The starter then has to fight the higher pressure, so if it is weak, or your battery is low, you may not have enough juice to fire it right up.

 

[Larry Bastanza]

With the car idling, blip the throttle. If the idle dips to almost stall, then bounces back, or if it stalls completely, first thing you need to do is clean the throttle body idle passage, it is clogged.

My $.02

Regards,
LarryB

 

[Bahta1]

LarryB, that's a very good too, as I have been experiencing that for about a year. Do you have a source for that tip? (not trying to hijack this thread)

 

[Larry Bastanza]

LarryB, that's a very good too, as I have been experiencing that for about a year. Do you have a source for that tip? (not trying to hijack this thread)

I do not understand your question about source? If you mean where did I learn this it is from the article I wrote for NSXDriver 6+ years ago......

Regards,
LarryB

 

[Bahta1]

Ahh yes, that's fantastic LarryB, thanks. I don't suppose there is an archive of that article I can reference so I can figure out how to do it?

 

[nsxtasy]

Jackson, since you are new to the NSX and apparently new to this site, it's worth pointing out that Larry B is, among other accomplishments (as well as a very nice guy), one of the most experienced NSX mechanics in the country.

(Not to take anything away from the advice posted by others, many of whom are also very knowledgeable.)

 

[Big_D]

Ahh yes, that's fantastic LarryB, thanks. I don't suppose there is an archive of that article I can reference so I can figure out how to do it?

http://www.nsxprime.com/forum/showthread.php/56821-NSX-Driver-Magazine-s-Throttle-Body-Cleaning-Article?highlight=throttle%20body%20cleaning

 

[dablackgoku1234]

the engine takes a lot longer to start when it is warm than when I first crank it in the morning. It's nothing too crazy, but it turns over for a few seconds before it kicks - is this normal?

I have the same issue. Have not figured out what the deal is, but the speed of my "crank" is the same when the engine is hot or cold. Just that when the engine is hot, it cranks for a good 5 secs before finally starting.

 

[ftuhy]

One thing that happens in some cars, and possibly in the NSX is "vapor lock". The hot engine causes fuel to vaporize in fuel lines touching or very close to the engine. It then takes a few seconds to blow out the vapor and have liquid fuel in the injectors.

Another possible cause could be (slightly) leaky injectors.

And yes, sometimes my NSX does this too, especially in hot weather.