Lack of power - probable causes?

dquarasr2

dquarasr2

Experienced Member
Joined
9 September 2005
Messages
1,455
Location
Central FL
Yesterday I took the NSX out to spectate at a car show. Drove about 5 mins to a highway, drove about 3 miles at 70mph, then again on side streets.

After I got off the highway I noticed the car felt as though it had a boat anchor attached. Would not accelerate normally. I'd then press a little harder on the gas and it would then accelerate normally. Seemed to have a problem with part-throttle load.

I pulled over and looked around (I thought maybe it had a flat and there was drag). The exhaust smelled awful, as though the fuel was not being combusted correctly. Almost like when you're behind that 25-year-old poorly-running lawn maintenance pickup truck. Didn't smell like raw fuel, just smelled like very poor combustion.

I parked it, walked around the car show about 15 mins, then drove it home. Behaved comletely normally.

I consulted with my son, who says that Hondas often have a problem with either sticking fuel injectors or bad temp sensors. Either would explain how it felt: it definitely felt as though it was running way rich and only cleared when I opened the throttle significantly more. BTW, it was at RPM's less than VTEC actuation.

Any ideas on where I can look? The 'puter threw no codes, no CEL.

Could this be lack of use issue? Sticking solenoids and / or relays in the fuel system? Sticking injectors?

Thanks.
 
I see you are in South Florida. Was you car subjected to alot of rain? Wet plug wires can cause arking and drop a cyl. This is common and there are multiple threads on this.
 
Thanks for your reply.

Car is almost never driven in the rain. But I will take a look. Usually plug wires manifest as a distinctive miss, which I know what would feel like.

This wasn't an outright misfire; it was more like a plugged cat but a plugged cat wouldn't usually clear up with more throttle.

It definitely felt like fuel delivery. I am sure it was not lean (hesitation is very distinctive); it really did feel like it was loading up (rich) and sure smelled like it.
 
Last edited:
What year NSX? Drive-by-wire or cable to the gas pedal?

Even though you didn't get a MIL, check for stored codes that may have come in briefly and cleared.
 
ftuhy:
'91

I will pull the codes as soon as I can. Thanks for the suggestion.


EdinKali:
No, have not filled up recently. Have just over 1/4 tank available.

Thanks all, for responses. Keep 'em comin'. :biggrin:
 
I have average auto mechanical/electrical skills but if I have learned anything in my years of ownership 8/10 intermitant gremlins without codes are O2 sensors, main relay fizzles,or gunked up throttle bodies.......there I shot my total wad:redface:
 
Could be bad O2 sensor, but could also be bad Throttle Positioning Sensor (TPS). Lack of power and sluggishness would lead me to believe it was the TPS. A bad TPS doesn't necessarily throw CEL's. Another issue with a bad TPS is a higher than normal idle. If your idle is around 1200RPM that would also lead me to think the TPS was defective.
Good Luck!
 
I could believe a bad O2 sensor. I replaced the easy-access O2 sensor about two years ago, but it had thrown a code. The other is as far as I know the original.

I have done the main relay by resoldering all the joints about three years ago. But I understand when that fails it usually shows itself as hard / no starting (which it did before I refurb'd it).

As far as TPS, could be, but the idle was normal.

Again, this was weird, it idled well, accelerated to a point normally, then just wouldn't go as expected under medium throttle. Push past it and it would clear its throat and go. And it was very intermittent.

I don't know if it could be vapor lock: it was really, really hot out. Poor fuel pressure can cause vapor lock but again, I don't think so since it didn't have a problem after it sat a few minutes and I restarted it. If it was vapor lock it would have been even worse after it sat and heat-soaked.

I guess I am just going to have to wait until it happens again and see if it is worse and more repeatable before I can diagnose it. I'll also pull codes to see if it stored any.

I'm really hoping it's from lack of use and sticking relays and / or injectors that can be solved by just driving the darned thing. Now if the weather would cooperate by not raining *every single day*, I'd be happier.

Thanks to all that have made suggestions.
 
You mentioned that you have not filled up recently and have a quarter tank.

Ethanol issues?

I'd put 10 gallons of 93 octane in there and drive the heck out of it. Cleaning your throttle body is also a good preventative item to do.
 
kookoo4nsx said:
You mentioned that you have not filled up recently and have a quarter tank.

Ethanol issues?

I'd put 10 gallons of 93 octane in there and drive the heck out of it. Cleaning your throttle body is also a good preventative item to do.
Click to expand...

^This^ I had trouble with both motorcycles and various other sports cars.
The Ethanol absorbs water vapor from the air and degrades the fuel very quickly. Try a fresh tank and good TB cleaning.
 
DRIFTER said:
^This^ I had trouble with both motorcycles and various other sports cars.
The Ethanol absorbs water vapor from the air and degrades the fuel very quickly. Try a fresh tank and good TB cleaning.
Click to expand...

OK, Thanks Drifter and kookoo. I'll put in some fresh 93 and see what happens.
 
If your problem continues, my guess would be a worn/old fuel pump.

My NSX would hesitate/bog around 2000-3000 RPM, then it would accelerate quickly once you get pass 3000 RPM. My fix was installing a new fuel pump. You can put a guage on your fuel filter and check your fuel pressure to give you an idea if it might be the fuel pump.
 
Now that sounds most like the symptoms I experienced, NSXclear. I will definitely do this (edit after I posted first posted this reply: I meant I will check fuel pressure and if low then get a new pump). I plan to do this and pull the codes tomorrow and check the other recommendations posted here. I'll post what I find.

Thanks again, all, for the help and suggestions.
 
Last edited:
Resurrecting a thread of mine from August.

This past Friday night, same thing. Stumbled at part-throttle around 2k RPM, press a little harder on the accelerator then it takes off. Car had been running fine since August. Very intermittent.

May be coincidental, but cruising at 45 MPH threw a CEL. Car ran smoothly while the light was on.

Turned the car off at a stop light and restarted. CEL gone.

On the way back home that night car ran OK but threw another code. When I put the car to bed after I got home, CEL was on.

First thing next morning pulled the code: nothing. Started the car, no CEL. (WTH?)

I talked to my son and he seems to think TPS. If it is bad, the throttle would be open but the fuel delivery would be leaner than needed. I don't know, I'm grasping at straws here. Recall that the first time this happened, the exhaust smelled all kinds of foul, but did NOT smell of unburned gas. Just funky like ignition was incomplete and with all kinds of pollution. Didn't get out and check this time, although I would assume the same would be true.

So, without a CEL code I'm hesitant to start throwing parts at it. I will, though, check the fuel filter and put a fuel pressure gauge on it. I will report back when I have had a chance to do so.

Again, ideas welcome. Thanks for everyone's help.
 
Briank said:
If the cel light comes on a code is being stored, you are shorting the diag connector to get the code? From what you have described a O2 sensor issue is at the top of my list next would be the main relay.
Click to expand...

Yes, strange. I jumped the blue connector in the passenger footwell per procedures and got nothing. I have successfully pulled codes in the past. I tried it three times to make sure I was jumping it properly with high-tech paper clip. :smile:

When I started the car again CEL was off. I thought codes were supposed to be stored if the light was thrown. I'm confused.
 
when my X was doing this it turned out to be a bad spark plug. I know that in other cars when there is a bad plug there is an obvious sputter, but my NSX didn't do that....it would heasitate at partial throttle. fresh plugs, no mor CEL's and no more flooded feeling
 
chrisbailey13 said:
when my X was doing this it turned out to be a bad spark plug. I know that in other cars when there is a bad plug there is an obvious sputter, but my NSX didn't do that....it would heasitate at partial throttle. fresh plugs, no mor CEL's and no more flooded feeling
Click to expand...

Interesting. Thanks for tine input.

Was your issue intermittent? Mine is very much so.
 
Resurrecting old thread v2

OK, I'm going to resurrect this thread yet again.

Just picked up the car from Dwight at ForeignTech in FTL. Dwight did:
- T-belt
- misc seals, gaskets, filters as needed
- water pump
- drive belts
- spark plugs
- diagnosed SRS

He charged me a ridiculously low amount for labor. The total for all this work was $1600, which I believe to be completely reasonable.

(Aside: I had planned to drive up to Orlando to First Class and Nabil but the SRS light preempted that. Sorry, Nabil. SRS light was a fuse. Hmm, I checked ALL the fuses. :confused:)

On the way to work I got two CEL's. Both times I turned the car off and restarted, both times the light was gone. I am pretty sure both times happened right when I lifted off the gas and cruised for a little bit to slow for traffic in front of me. (This was at highway speeds.)

Then, when I got off the expressway and was in second gear accelerating normally around 2K RPM, the same hesitation I described in my original post happened again. Again as in my previous posts, I pressed harder on the accelerator and the car cleared its throat, accelerated normally, and did not misbehave again. And didn't throw a light.

I'm pretty sure when I get home tonight and pull the code I won't find one.

I suspect it's the O2 sensor, the one that was never changed (I believe it to be the original). I'll have Dwight throw in a new one in a couple of weeks, hopefully before I drive to Florida NSXCapades at the end of this month. He also mentioned that it might be a good idea to change the crank pulley; he said he has been stocking them but didn't have one this week. He looked at it and said it appeared fine but for peace of mind I think I'll have him change it soon.

I'll try to report back on what is going on if I find out more. BTW, the car has not had this problem in over a year, which is why it's so hard to diagnose.

Also, please note: I AM CERTAIN THIS HAS NOTHING TO DO WITH THE WORK DWIGHT DID as it has happened before and happened exactly the same way again today.
 
y not just replace the O2 sensor yourself? instead of waiting. it would drive me crazy if I cant figure out what causing the problem.
 
IWantNSX said:
y not just replace the O2 sensor yourself? instead of waiting. it would drive me crazy if I cant figure out what causing the problem.
Click to expand...

'Cuz I'm lazy and considering I think it's the original and has been in the car 21 years, it has the potential to cause me fits when I try to remove it. And from what I understand, it's not easy to reach.

And I've have to drive to my son's house to get the O2 socket, and it would prolly break off in the exhaust, and then I'd be all p*ssed.:biggrin:

Yeah, that's me, glass half empty.

Last time I ignored this problem it didn't come back for a full year. I think I'm secretly hoping it either goes away or comes back and stays so I can definitively diagnose it.
 

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