I failed emissions!!! :(

DanRC30 said:
The comptech headers relocate the O2 sensor right behind the oil pan which is a HUGE benefit. It's almost worth getting the header just for that alone!
Click to expand...

Great, let us know what the outcome is. (I know you will) We've got to get this fixed. BTW, I'm not too far from you at Ft Indiantown Gap, PA.
Brad
 
Will do.

Where can I get a wire extender for the O2 sensor? I'd rather not cut it if I can avoid it...
 
DanRC30 said:
Will do.

Where can I get a wire extender for the O2 sensor? I'd rather not cut it if I can avoid it...
Click to expand...

If it doesn't have one on it now you don't need one. If it has one, you might want to take it off and do a continuity test on the 4 wires, and inspect the connector pins, just to make sure it is OK. Otherwise SOS sells them. I made my own using ends off of bad sensors and went to the salvage yard and got the other end off of a Honda Accord and then solder the four wires together. Take the old O2 sensor with you and match it up. I think it was a 93 Accord. It only needed to be about 6 inches long, but I was using NA2 OEM headers. Yours will be different.
 
The lead on my front sensor is longer than the new one I got. I don't know if it was spliced or not... I'll have to look more closely next time I'm under it.

Can you link me on the extender piece?
 
ralph cerbone said:
i generaly will not give an opinion with out all the gas results ,but i will go out on a limb on this one
HC === is unburned fuel,caused by cyl. misfire, lean condition, ignition, eng mechanical problem,oil contamination (gas in oil)
CO ===== rich condition ,oxygen depravation (lack of air not too much fuel)
NOx==== lean condition( rich condition kills it )
O2==== high o2 lean condition,
CO2=== this is the most important, not for the tree huggers,it tells me the condition of the engine, we like to see at least 13.5,higher better, CO2 is a combustion efficency indicator (when i get a call i wont respond with out it )
it appears you have made quite a few adjustments to this car , but based on the above readings, this is what you have ,CO is close so you must be in fuel control, HC is way out , 100ppm is way to fat for this car , NOW I WILL GO OUT ON A LIMB, providing the engine is sound,your are pulling at least 20 inches of vacuum at idle (map sensor signal hose, this will comfirm valve timing is correct) CHANGE YOUR OIL and retest !!! Ihave have been involved with these tests since the beginning of the N.Y.S. emissons in 78 , last year had a very similiar situation , AGAIN JUST A GUT FEELING BASED ON THE DATA PROVIDED hope it helps
Click to expand...

I had the oil changed at the same time when the timing belt job was done.
 
I don't have a scanner, and I don't have the latest readings because they are in the glove box of the car and the car is at the body shop getting its fender replaced from my g-friend's brother-in-law backing into it.

I just can't win... :(

I should have it back by Thursday as good as new. I plan on disconnecting the battery and then trying inspection again. If I fail again, I'll post the latest readings. I also plan on trying to get the O2 sensor out and replacing it. I'll do that before I go to inspection if I can.
 
when life hands you a lemon ,make lemonade, look i not saying its not a bad O2 its just i dont like seeing people changing things randomly and creating more problems, meantime i look at the n.j. testing procedure , after fixing these problems for thirty yrs it always goes back to basics
 
I passed!!!!!!

Barely, but I did. We got the old O2 sensor out, and put the new one in. I drove it about 3 miles just to heat it up and I went through inspection and I passed! I'm so relieved.... The CO was .49, but that's under .50, so I'm all good!!! :)

Thanks all for the help! :biggrin::biggrin::biggrin:
 
Me too, but remember... In addition to only driving it for about 2 or 3 miles after swapping the O2 sensor, I reset the computer by disconnecting the battery. So that also may have something to do with it... I think if I drove it for about 100 miles it's go lower...
 
now i have to take you back to late 70s early 80s , all auto ecms had what was called green cells ,or engine breakin programs, (snap on scanner would actually show status of cell), after so many miles it would change program of engine, if you thought you had a bad ecm ,car had low miles & put in an ecm from a car which had high miles you would end up with an ecm running on a richer program , used do drive guys crazy, but we got smarter and figured it out, just dating my self but was a great learing period ,even the manuf. didn"t realize it,been doing this a long time
 
The last time you tested, you failed on HC but passed on CO. I'm curious about what the HC # was this time. Modern computer controlled cars may use adaptive learning for fuel trim, and it is only a trim. The immediate O2 sensor reading gets the AFR to a pretty tight range on its own, and should be just fine to pass a smog test with flying colors. Regardless, the short-term learning happens in minutes, if not seconds, and long-term learning is typically fleshed out within a few miles.
Running rich robs performance. Get this fixed and enjoy the car at its potential.

Quick question: at what RPM does the fuel cut-off happen? Does it redline above 8000?
 
HC was 96, and CO was .49.

Both very close to not passing. I think the other O2 sensor might be on its way out as well... perhaps I should change it.

I haven't hit the rev limiter yet... not really looking to do that either.
 
I've been following this thread and and am happy to read you got it to pass.:smile: Now you can really enjoy the car without thinking about emissions. Now go blast onto the freeway on ramp and make a long 2nd gear pull to redline and see what is so wonderful about the 5 speed. :biggrin:
 
Daedalus said:
The last time you tested, you failed on HC but passed on CO. I'm curious about what the HC # was this time. Modern computer controlled cars may use adaptive learning for fuel trim, and it is only a trim. The immediate O2 sensor reading gets the AFR to a pretty tight range on its own, and should be just fine to pass a smog test with flying colors. Regardless, the short-term learning happens in minutes, if not seconds, and long-term learning is typically fleshed out within a few miles.
Running rich robs performance. Get this fixed and enjoy the car at its potential.

Quick question: at what RPM does the fuel cut-off happen? Does it redline above 8000?
Click to expand...

your close in your interpation , does the # 128 or 256 , a percentage of fuel trim mean anything !!! this is where it all began!!
 
Last edited:
ralph cerbone said:
your close in your interpation , does the # 128 or 256 , a percentage of fuel trim mean anything !!! this is where it all began!!
Click to expand...

I know them as terms used with GM's integrator and block learn PCM functions. The car starts at 128 and learns from there. A car on a stationary dyno should stay at 128. I don't think we need to wander down memory lane for this, unless you think fuel trim could be responsible for those #s. HC ought to be under 10 ppm and CO ought to be around .01% on a healthy NSX. An ECU malfunction is a very unlikely candidate. I would sooner guess at a bad temp sensor, hence my question about the redline.
 
Daedalus said:
I know them as terms used with GM's integrator and block learn PCM functions. The car starts at 128 and learns from there. A car on a stationary dyno should stay at 128. I don't think we need to wander down memory lane for this, unless you think fuel trim could be responsible for those #s. HC ought to be under 10 ppm and CO ought to be around .01% on a healthy NSX. An ECU malfunction is a very unlikely candidate. I would sooner guess at a bad temp sensor, hence my question about the redline.
Click to expand...

totally agree ,was not suggesting ecu replacement ,
 
DanRC30 said:
HC was 96, and CO was .49.

Both very close to not passing. I think the other O2 sensor might be on its way out as well... perhaps I should change it.
Click to expand...

Dan,
That might not be a bad idea since your numbers are that close to a Failed Test. Run a couple tanks of Quality Premium gas through it and then stop and get it checked again after a COMPLETE WARMUP and see what you get for numbers and then decide. Glad to hear you are back on the road.
Brad
 
Just got my emissions done. I was a little worried about passing since I am running test pipes. I pulled up to one of the bays and they motioned for me to get out of line and just park on the side of the building. I went inside and the guy just gave me a pass notice. Didn't even do any testing or charge me any $$$!!!!! All he said was "nice car". :tongue::smile::cool:
 
HC: 92 (max: 85) failed on this
CO: 0.43 (max 0.50) passed on this
NO 702 (max 695) failed on this.....

U can see my mods in my signature... what are my options? I'm out $80 and about 5 hours of my time here..... :mad::frown:
 
Last edited:

Similar threads

B
What is this on my dash
Replies
12
Views
264
drew
drew
Ron1999
P0171, CEL light but car is running ok (1996 NSX-T, 100K miles)
Replies
3
Views
109
Ron1999
Ron1999
TANTO
EXHAUST SMELL
Replies
5
Views
317
TANTO
TANTO
jsullyboy
Low Engine Power before 4k RPM
2
Replies
29
Views
783
NSX78__
NSX78__
Ron1999
Mounting the EPS module due to an aftermarket Sub (or if you just feel like it)
Replies
0
Views
69
Ron1999
Ron1999
Back
Top