There's no O2 left in the exhaust. I would guess O2 sensors or water temp sensor. If the temp sensor is off, the ECU will think it's colder than it really is, and run rich to compensate. Again, seems like a marginal problem. If it was bad CO would be much higher, along with HC.
all NSXs pass california smog test?
- Thread starter MBANSX
- Start date
Cerritos Acura said they checked the O2 sensors and they're fine.
Yes, I agree. This seems like a very marginal problem, probably caused by having the car sit for too long in the garage.
Hopefully Acura can find a way to fix it.
Yes, I agree. This seems like a very marginal problem, probably caused by having the car sit for too long in the garage.
Hopefully Acura can find a way to fix it.
1. There's really no way to test an O2 sensor without a lot of expensive equipment that dealerships don't have.
2. The car does not have spark plug wires.
If it was my car and I wanted it to pass, here's what I would do:
1. With a can or carburetor cleaner, I'd spray and wipe-up the throttle body as much as possible. Get everything shiney-clean and try to get into all of the orifices. Do as much as possible with the car running.
2. Change the oil and filter. I'm not sure if it's true or not, but I've ready plenty to suggest that this may make a difference. Easy enough, just do it.
3. Change spark plugs. Again, easy enough to do.
4. Fill up with a good gas - I'd recommend 76 or Chevron.
5. Drive the car before the test... and be a little more aggressive on it. Don't flog the car, just don't drive like a girly-man.
6. Arriving at the SMOG station, don't turn off the car. Let it run and keep the cats hot. If you have a chance, idle up at 1800 RPM for a minute or two before the test starts.
My $.02. (From experience.)
2. The car does not have spark plug wires.
If it was my car and I wanted it to pass, here's what I would do:
1. With a can or carburetor cleaner, I'd spray and wipe-up the throttle body as much as possible. Get everything shiney-clean and try to get into all of the orifices. Do as much as possible with the car running.
2. Change the oil and filter. I'm not sure if it's true or not, but I've ready plenty to suggest that this may make a difference. Easy enough, just do it.
3. Change spark plugs. Again, easy enough to do.
4. Fill up with a good gas - I'd recommend 76 or Chevron.
5. Drive the car before the test... and be a little more aggressive on it. Don't flog the car, just don't drive like a girly-man.
6. Arriving at the SMOG station, don't turn off the car. Let it run and keep the cats hot. If you have a chance, idle up at 1800 RPM for a minute or two before the test starts.
My $.02. (From experience.)
Check to see if there is an aftermarket computer in the car, that can sometimes cause a rich mixture. If all else fails, "cocktail" the fuel with "BG's" 44K, cleans up the emissions (even though this works, it is a tempory fix and not socialy responsible). For top end cleaner, try GM top end cleaner, two cans in a vacuum hose and let the engine die. Let the engine set for several hours and restart, SMOKE! to the max, sometimes this can cause impact damage to spark plugs. On 95 and newer OB2 cars it can set misfire codes, this stuff cleans carbon well. There are other products out there, but I have no personal experience with them. By the way, an oil change does help emissions, not much but does help. Also do some type of engine condition test, compresssion or leakdown (preferred), even electronic is better then nothing, good idea on a used car. If the engine is burning oil that can cause emission problems. I hope this helps. Good Luck. Steve V.
From my prior experience. 15 mph in first gear. 25 mph in 3rd gear. PASSED.
my smog FAILED with 1st gear for 15mph, 25mph 2nd gear. I have a supercharger also.
As suggested before drive it in higher rpm and keeping it their before arriving.
Danny
my smog FAILED with 1st gear for 15mph, 25mph 2nd gear. I have a supercharger also.
As suggested before drive it in higher rpm and keeping it their before arriving.
Danny
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Since this thread is on the smog subject. Here's a link were you can view previous smog tests. Just need to enter vin or plate number of the vehicle.
http://www.smogcheck.ca.gov/applications/VehTests/PubTstQry.aspx
http://www.smogcheck.ca.gov/applications/VehTests/PubTstQry.aspx
Can anyone let me borrow their cats for a day? I need to see if i can pass emission.
John
John
I bought an out of state car also, a 93 with 50k miles and it runs really nice. But, it failed smog big time like your. We changed plugs(they looked old), O2(they look old but ok), carbon clean engine(it helped a little), air bleed cooling system(the system was 1/2 gal low)....all of the above needed to be done but it still did not make much difference.
All shops told me the nsx cats rarely go bad but after i installed 2 Random cats from SOS, the car spent less than 1 min. on the rolller and passed.
A lot of money spent but now I know the condition of the engine. I still don't know what could kill the cats with so little mileage.
Random tech cats can pass california smog test?
it did for me. the price from SOS is a lot lower than oem cats. If I bought the Random cats first, I would've save a lot of money but I think all the "extra" stuff I did was also needed but not enough to pass the smog. I basically had bad cats so no matter how hot I keep it up, it would still fail.
yea, it seems like we have the same problem. I wonder if replacing my oem cats with SOS random tech cats would solve my smog problem.
my HC and NOx were high even with all the "extra" stuff done to it "one at a time" and retest one change at a time but still failed bad. the one helped the most was the carbon clean which showed most improvement, this was done at Greenlight by Jerry.
The Test Only station I went knew what they were doing and after the new cats, it barely spent any time on the roller and it was done.
Jerry knew how to read the smog number so i did not think the carbon clean he did was waste of money. Chris at SOS also saw the numbers but found the car had old plugs and 1/2 gal low on coolant so he fixed these first before recommend something else based on the re-test.
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As said before, there is no way to know about the O2 sensors being bad but: You can't pass and the numbers suggest the O2 is bad. Just replace it?
Cats are another area to look at too..
Cats are another area to look at too..
If the O2 sensors are bad then my check engine light should come on or i would get some error code. But i didnt get any of them.
Since no one is 100% sure that the cats is the problem, I want to borrow cats from someone (for a small fee, of course) to test.
Since no one is 100% sure that the cats is the problem, I want to borrow cats from someone (for a small fee, of course) to test.
MBA:
i wrote all(5) tests for you to see but when I tried to post, i was all gone
my NOx was in the 1000+ and my HC was high (even after new plugs and new O2)
what did it were the cats.
You should take it to autowave in HB as they know how to read/diag. the probable cause. otherwise, you are running around in circles guessing.
it cost me a lot but now I have a peace of mind knowing my motor is very clean and healthy. I had 46k when I bought it so it did not occur to me it may need plugs, O2, coolant...etc. as it runs really nice and get great mileage.
an used/unknown/not sure condition cats may give you high reading too....then you'll be really spinning.
i wrote all(5) tests for you to see but when I tried to post, i was all gone
my NOx was in the 1000+ and my HC was high (even after new plugs and new O2)
what did it were the cats.
You should take it to autowave in HB as they know how to read/diag. the probable cause. otherwise, you are running around in circles guessing.
it cost me a lot but now I have a peace of mind knowing my motor is very clean and healthy. I had 46k when I bought it so it did not occur to me it may need plugs, O2, coolant...etc. as it runs really nice and get great mileage.
an used/unknown/not sure condition cats may give you high reading too....then you'll be really spinning.
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- 2 February 2009
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did any of you with trouble get your car to pass smog in california?
I have 93 with 171K miles...my commuter car
failed 2 yrs ago and got a waiver.
failed again last month...replaced 02 sensors, and added new OEM cats.
also, spent 1 month at Acura dealer, 1 month at local shop, 1 week at Gold Shield repair place where they went over timing, plugs, egr valve, and about 1000 other things that could be the problem.
nobody knows what the problem is...
acura of course wants $2500 for the Acura NSX 91-94 cats...is this my only option or has anybody used other cats that pass Ca. Test Only?
Jen
I have 93 with 171K miles...my commuter car
failed 2 yrs ago and got a waiver.
failed again last month...replaced 02 sensors, and added new OEM cats.
also, spent 1 month at Acura dealer, 1 month at local shop, 1 week at Gold Shield repair place where they went over timing, plugs, egr valve, and about 1000 other things that could be the problem.
nobody knows what the problem is...
acura of course wants $2500 for the Acura NSX 91-94 cats...is this my only option or has anybody used other cats that pass Ca. Test Only?
Jen
did any of you with trouble get your car to pass smog in california?
I have 93 with 171K miles...my commuter car
failed 2 yrs ago and got a waiver.
failed again last month...replaced 02 sensors, and added new OEM cats.
also, spent 1 month at Acura dealer, 1 month at local shop, 1 week at Gold Shield repair place where they went over timing, plugs, egr valve, and about 1000 other things that could be the problem.
nobody knows what the problem is...
acura of course wants $2500 for the Acura NSX 91-94 cats...is this my only option or has anybody used other cats that pass Ca. Test Only?
Jen
Did you make sure the Cat's were nice and hot before they did the test?
- Joined
- 2 February 2009
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I have taken about 10 smog tests on the dyno. they replace and check parts and resmog every time to see if things have changed.
...cats hot everytime..
dealer wants it back to confirm it is cats before buying them for big bucks...guess the ones I put on last month will be trash if they don't
pass the test dealer gives them .....
anybody have experience with computer being off and pumping in too much fuel? or fuel injector malfunction being the issue for smog?
...cats hot everytime..
dealer wants it back to confirm it is cats before buying them for big bucks...guess the ones I put on last month will be trash if they don't
pass the test dealer gives them .....
anybody have experience with computer being off and pumping in too much fuel? or fuel injector malfunction being the issue for smog?
Let's see it. Post up the #s. Sounds like you're being charged for someone else to guess. Guys here will do it for free. 
You can find used cats on the NSXPrime Marketplace or look at the group buy section for hi flow cats made by ProSpeed. No sense of wasting a couple grand to buy new ones.
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here are my latest numbers...
hc co2 no
15 mph 273 1.16 1421 over on all three
25 mph 119 .30 627 over on hc only at high speed
hc co2 no
15 mph 273 1.16 1421 over on all three
25 mph 119 .30 627 over on hc only at high speed
I got to see that :tongue:
How many miles on the car? Maybe you might need to check the compression. You might have a valve issue or ring problem. They should be able to check your o2 readings and see whether your cat is working. The car will only code if the cat is really bad, but if it is just boarderline it will not code. Your readings are not that far out of line. This is not a good sign if you are planning to buy the car. Good luck.
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- 5
171 K miles, of which 105K I put on over the last 9 years.
I passed smog every time til 2 years ago.
compression test checks out fine. put in new o2 sensors even though
it didn't need them.
Gold Shield mechanic says cats are probably not working...are universal cats from magnaflow that are for 93 NSX??
this is the second set I have tried on this car..
I passed smog every time til 2 years ago.
compression test checks out fine. put in new o2 sensors even though
it didn't need them.
Gold Shield mechanic says cats are probably not working...are universal cats from magnaflow that are for 93 NSX??
this is the second set I have tried on this car..
Not on a '93. Both sensors are before the cats. And there's no easy way to read them, other than piercing the wires to tap a scope. Not a bad idea though; at least you would know if one bank is running richer than the other or if they're both the same.
The readings are pretty bad. Definitely running too rich, which unfortunately doesn't explain the high NOx reading. Have the shops done a rail leak-down test and verified the ECU water temp sensor is working right?
Did the car begin to fail smog the 1st test after the new O2s were put in, or before that?
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