so how much is this part and whether it is compatible for NA1 engine?
Where about is this location on the engine?
GL...
Is your NSX failing smog? Read this.
- Thread starter johnnymo
- Start date
so how much is this part and whether it is compatible for NA1 engine?
Where about is this location on the engine?
GL...
http://www.nsxprime.com/forum/showthread.php?t=150753
The max NO used to be 785/724 (15/25 mph) now its 549/507
http://www.autorepair.ca.gov/pubwebquery/cutpoints/ShowResult.aspx?VLTROWID=22428
If you have a 92 or an automatic the numbers haven't changed
http://www.autorepair.ca.gov/pubwebquery/cutpoints/ShowResult.aspx?VLTROWID=22427
http://www.autorepair.ca.gov/pubwebquery/cutpoints/ShowResult.aspx?VLTROWID=23345
I emailed CARB and they actually responded, while I don't agree with the philosophy of changing the limits they do based upon our test averages. So when they get a large enough sample of cars from a model year they move the limits to reflect the "actuals". So the 91s limits changed since there are the most of them and the just changed the Manuals, the Autos did not have enough samples. It's all a numbers game by the model and year they don't concern themselves with the reality they are all the same engine.
My car failed also do to faulty parts in the EGR system (don't know which cause they guy replace almost all of them the last being the EGR valve).
The problem I have with use the "actuals" is that I'm always hearing about people paying to pass or using different tricks. Well I figure that just skews the average even lower.
Funny thing as I was reading up on the EGR and the SMOG testing I've come to the conclusion the whole thing is a shame where the car mfg setup a system to pass the test. If you can adjust your EGR valve to open during the smog test you will pass. I suspect if you could tweak your ECU to command the EGR even more open and over a wider range it would pass even easier. I say that because in my case due to a faulty position feed back signal from the EGR valve it was half as open as it should have been. My NOX dropped 300pm when the EGR valve was replaced.
I understand this is why daedalus measures the vacuum on his EGR that's a direct diagnostic if the smog test is being run in the sweat spot and all the ECU inputs are being received. Don't be surprised if a smog tech takes exception to the extra tubing because you could also be adding vacuum to pass the test. That's how the smog tech that worked my car convinced me I didn't need to buy new CATs he applied extra vacuum and the car passed.
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I just got around to installing a new temp sensor I ordered when I first saw this thread. My original sensor had more carbon caked on then most of the pictures here, I was pretty shocked. The car has always run perfect and passed smog inspections but I expect I'll have even better results now.
Glad to hear my experience was helpful, MrTwo. Several NSX owners in So County OC have been shocked as well when the pull the part.
I just failed smog in my 1991 with 32k miles. TCS was off, not sure of the gear. I didn't hot rod the car before coming in. The technician noted that he didn't think the car would pass because he said it sounds like my cats were gutted (which I highly doubt) as the car is in the same exact condition for 7 years.
I'm going to clean this sensor and try again tomorrow and try again.
I'm going to clean this sensor and try again tomorrow and try again.
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^That's pretty bad. How much did you drive it before getting tested? Did it sit much before the test? Did the tech at least rev it up a bit? It's almost as if the car was completely open loop with cold cats during the 15mph test, and then on the 25mph test the car went closed loop, but the cats still weren't quite hot enough. It's rather rare to see leftover O2 with HC, NO and NOx numbers that high. A fouled up temp sensor can't cause both high HC and high NOx. It was in 2nd gear the whole time, and that's kind of iffy @ 15mph (too low an engine speed). But 2nd gear is what the tech is required to test at.
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I drove it from work to the shop without VTEC or WOT, and it sat for about 5 minutes before he pulled it in.
Here's the dirty sensor:
So after cleaning the sensor and driving the car about 5 miles hard and rolling it right onto the rollers, I passed. The failed results were from 2 days ago.
What sensor did you clean btw .
Air Intake Temperature sensor, you can view information about it on page 1 of this thread.
Look at the numbers on my above post on 8/3/12. How can we expect these cars keep running cleaner as they get older?
Looking at your numbers, I will have a hell of a time passing next year.
My passing test from 8/3/12
Looking at your numbers, I will have a hell of a time passing next year.
So after cleaning the sensor and driving the car about 5 miles hard and rolling it right onto the rollers, I passed. The failed results were from 2 days ago.
My passing test from 8/3/12
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There are only so many items that can have much of an impact on smog tests, the most expensive of which is the cats of course (and those should probably last the longest, assuming the other ones are working well). Proper diagnosis is all that's required to either pinpoint problems or exonerate suspects. Unfortunately--and I rarely say this--I would not rule out cat efficiency being suspect in the results posted.
At any rate, the rest of us should be thanking you guys for keeping the average up.
At any rate, the rest of us should be thanking you guys for keeping the average up.
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Why do you think the passing criteria keeps going lower?
Do you really think the cars are running better 20 yrs later?
Or are folks faking out the machines to pass causing the numbers to drop?
Do you really think the cars are running better 20 yrs later?
Or are folks faking out the machines to pass causing the numbers to drop?
Rope is correct. The CARB merely sets targets and standards that get tighter over time. My understanding is that, from those targets, they come up with is a statistical method of reducing some % of pollutants from each model they track, to meet the overall goal. The smog results show averages, which are specific to your model car. I'm sure there's a CARB database somewhere that looks at standard deviations, and calculates what the new limits should be. The CARB doesn't care if cars are made to run cleaner or are taken off the road, as long as the numbers are met. It may be possible that if all NSXs started blowing the same numbers as the posted test results, the limits would go up (again, thanks for raising the average). I doubt the limits have anything to do with how much pollution a brand new car puts out, so it's not a case of needing to run better than new. IIRC my car @ around 60k miles beats the average on HC and CO, and is just over average on NOx. The max #s are very loose considering where the averages are. That said, I realized that the guy I bought my car from did cheat to get the car to pass (just so he could sell it to me). The rev limiter would kick in @ 7000, and I verified from his last smog report the gear ratios did not match the car. Luckily I was able to guess what the issue was and verify it, and it was only a water temp sensor. No problems since.
Just curious if you would recommend cleaning the EGR if the NOx numbers are fairly low (below 250 at 15mph and 150 at 25mph)? Thx.
I wouldn't bother. It sounds like it's doing its thing and working fine. There aren't any performance benefits to be had...if you're passing smog then it's good enough.
My AIT Sensor was crudded up like others in this post. I bought a new one for about 30 bucks shipped, put in new plugs, oil change and recharded my K&N filter, so hope that does the trick.
I just tested my 92 today and it failed. emission guy said 90% of his fails are from cars 95 and older. My car passed April 2012 with fying colors so I assume a fuel additive was used or an emissions guy was "paid off". NOx level in april 2012 was 135!! yeah right. Today is was 1100 with 878 allowed. So I am going to replace the the IAT sensor like you guys suggest, run the cats until there hotter than haites, and use a octane booster and cross my fingers.
- - - Updated - - -
- - - Updated - - -
Oh and the gas cap failed too..lol Just order a new one with the IAT sensor, I'll replace tomorrow and let you guys know how it went
Re-test today was a success. Thanks to this thread. Changed the sensor and added some octane booster and got the cats plenty warm, made a huge difference. Here is the 92 nsx emission kit lol
Been 2 years since i replied and never went for an e test till this year. Ive done a lot which likely contributed to the now low numbers however my idle still has somewhat high HC.
While I did a lot of things, its more likely that the IAT sensor is what allowed the car to pass. I write this siting at the DMV waiting to get my renewal stickers!
My 2500 rpm results were
HC Limit = 200, Reading = 25, Pass
CO Limit = 1, Reading = 0.01, Pass
Dillution = 12.55
Idle results were
HC Limit = 200, Reading = 170, Pass
CO Limit = 1, Reading = 0.02, Pass
Dillution = 12.77
I did go into the Etest with 8+ month old fuel mixed with probably older fuel from before and a dirty air filter. I was certain I wasnt going to pass so I didnt bother burning off the 3/4 tank of fuel and forgot to clean the air filter. I suspect the 170 HC number might get better if I had fresh fuel and clean air filter.
What has been done...
- oil change
- spark plugs
- IAT sensor replacement
Plugs were pretty fouled from before. Could be due to rich idle. I was getting 600-800 HC readings when i was failing.
Actually the IAT sensor didnt seem too bad. Some oil on it but not really that gummed up...
While I did a lot of things, its more likely that the IAT sensor is what allowed the car to pass. I write this siting at the DMV waiting to get my renewal stickers!
My 2500 rpm results were
HC Limit = 200, Reading = 25, Pass
CO Limit = 1, Reading = 0.01, Pass
Dillution = 12.55
Idle results were
HC Limit = 200, Reading = 170, Pass
CO Limit = 1, Reading = 0.02, Pass
Dillution = 12.77
I did go into the Etest with 8+ month old fuel mixed with probably older fuel from before and a dirty air filter. I was certain I wasnt going to pass so I didnt bother burning off the 3/4 tank of fuel and forgot to clean the air filter. I suspect the 170 HC number might get better if I had fresh fuel and clean air filter.
What has been done...
- oil change
- spark plugs
- IAT sensor replacement
Plugs were pretty fouled from before. Could be due to rich idle. I was getting 600-800 HC readings when i was failing.
Actually the IAT sensor didnt seem too bad. Some oil on it but not really that gummed up...
Pretty good readings. I'll need to do an etest soon. Stock cats? How many KMs on them?
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Thanks for the update. Changing oil brings HC down a little bit but by not very much. I still think you have minimal leak somewhere as HC is low at 2500 rpm and high at idle. Maybe worth checking for leaks in the air system. What about the injectors seals?
Stock cats. I have 2 sets of cats. Got an extra set when i was first failing almost 9 years ago. One set has about 120k on them amd the other has about 60k. Both sets have been used to pass. Keep the car running while u wait for the test.
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