smog check

Post by **dad240sx** » Sun Jun 09, 2013 1:51 pm

how many catalytic convertors is my 1995 240SX supposed to have?

Thanks

Post by **dad240sx** » Fri Dec 26, 2014 4:52 pm

I finally went for a CA smog check with the original stock exhaust installed, which had two catalytic converters. But my hood sticker and the smog check station's books say this car is only supposed to have one cat. So I failed visual inspection. Any body else have ths issue?

Post by **blkvrtswp** » Sat Dec 27, 2014 10:27 am

I believe S14 240SX has ONE cat (the upper one closer to the engine), then it has another OEM cat-looking thing specifically so it will pass visual inspection for lazy inspectors who do not notice the 1st cat. 100% from factory just like that. Not sure if this was all 4 years of S14 though.

Post by **2_Liter_Turbo** » Sat Dec 27, 2014 5:10 pm

All S14's have a pre-cat in the downpipe and the standard cat after the downpipe under the car. The techs are retarded for failing you. I'd go to another station.

Post by **jza80king** » Sat Dec 27, 2014 5:54 pm

Here is a diagram showing one CAT and then towards the back of the car another and then a Main Muffler....but yeah the place you went to sounds like they don't know what the hell they are looking at. Maybe they thought the 'muffler' was another Cat?

http://www.courtesyparts.com/240sx-part ... _3715.html

Post by **2_Liter_Turbo** » Sat Dec 27, 2014 6:16 pm

Post by **jza80king** » Sat Dec 27, 2014 6:19 pm

2_Liter_Turbo wrote:

Not part numbers 20300 and 20300N?

Post by **2_Liter_Turbo** » Sat Dec 27, 2014 6:37 pm

20300N is a exhaust resonator integrated into the exhaust. 20300 is the main catalytic converter. 20020 is the downpipe with integrated pre-cat. 20100 is the main exhaust muffler.

Post by **dad240sx** » Sun Dec 28, 2014 1:01 pm

The technician said that the under hood sticker on my car reads:

" EXHAUST EMISSION CONTROL TYPE: TWC/O2S/HO2S/EGR/SF1"

He says since it has 2 cat's, it should read:
" EXHAUST EMISSION CONTROL TYPE: 2TWC/O2S/HO2S/EGR/SF1"

and so "it must have been modified" and this fails visual inspection.

What do the stickers on your '95 240SX's say?

Thanks for all the help!

Post by **2_Liter_Turbo** » Sun Dec 28, 2014 7:13 pm

I actually don't have any stickers on my hood. I didn't see the emissions tag anywhere else either. You know, you can just tell him that it's a replacement hood... so it has the wrong tag, ha ha.

Post by **jza80king** » Mon Dec 29, 2014 8:42 pm

dad240sx wrote:The technician said that the under hood sticker on my car reads:

" EXHAUST EMISSION CONTROL TYPE: TWC/O2S/HO2S/EGR/SF1"

He says since it has 2 cat's, it should read:
" EXHAUST EMISSION CONTROL TYPE: 2TWC/O2S/HO2S/EGR/SF1"

and so "it must have been modified" and this fails visual inspection.

What do the stickers on your '95 240SX's say?

Thanks for all the help!

Good old Nazi California, my car is an S13 so I can't help you man. What happens if you get an aftermarket hood or something? Do they not think about that or do you need some CARB sticker for that also?

Post by **dad240sx** » Tue Dec 30, 2014 12:14 pm

I got an appointment at the Smog Referee station at Las Positas College. They did visuals and found some additional problems that actually, I am glad to know about. The car had heater hoses where it needs fuel rated hoses! They clarified the 2 cats issue and agreed that the hood sticker and the data base are not correct. They gave me some documents to verify that I have the stock set up in place. Then they rechecked and she failed NOS. I know its better to drive it till it gets really hot before a check. I guess that's how it passed on my first check. But at the referee station, by the time they ran the check she had cooled down. The car has 213K miles, are there any tips to get her to pass NOS? Should I run regular or premium gas? Would a Seafoam treatment help?
thanks!

Post by **jza80king** » Wed Dec 31, 2014 7:44 pm

NOS? You mean you failed cuz of high NOx? Can you provide the numbers the car ran when it was tested?

ka24ejunk · Post by **ka24ejunk** » Sat Jan 03, 2015 12:21 am

cant you keep the car running up into the test? thats what i do... then again my smog guy isn't too particular about visual. long as the sniffer passes hes cool. and that stupid gas cap test. then again my car is a 89 which is obd1

Post by **dad240sx** » Sat Jan 03, 2015 7:40 am

Yes sorry NOx failed. The number was 746ppm with ~500 being the max

Post by **jza80king** » Sat Jan 03, 2015 4:20 pm

dad240sx wrote:Yes sorry NOx failed. The number was 746ppm with ~500 being the max

high NO can be several things, usually some sort of misfire or lean combustion. I would try the basic/cheapest fixes first. First check your timing and change any old spark plugs/wires then distributor cap and rotor. Next I would check for any air leaks, you might have some sort of vacuum leak. Before I rebuilt my motor I got a regular spray bottle and put dish soap with water and ran the car and sprayed around and found a lot of bubbles from my old a** vacuum lines. Spray the vacuum lines, and around the throttle body housing hoses carefully and see if you can pinpoint bubbles etc. Replace vacuum lines if necessary. Excessive carbon build up can also cause a lean running car, I in the past have seafoamed my car and gotten good results with reducing carbon buildup, seafoam is maybe $10 and follow the 1/3 method, if you dunno you can search or I can tell you. Check the AFM make sure it's not dirty and you might consider AFM cleaner to spray it off and let it dry off. Since your are by the AFM, replace the air filter if necessary. High NO numbers could also be a little more expensive things like the O2 sensor(s). Your EGR valve definitely might need to be cleaned out with carb cleaner or throttle body cleaner and most likely PCV valve would be a good idea to replace if it's been a while. The PCV is cheap, but it's a giant b**** to get to, I had to remove the alternator to get to it. Last and most expensive is probably the Catalytic convertor. I would do everything and then leave this for last but hopefully your cats are not bad.

I failed a couple years ago for high NOx and HC and I did exactly the above and was able to get my car passed without shelling out more than $30 and not having to replace my cat on my 92 240sx. Good luck man.

Post by **dad240sx** » Wed May 06, 2015 10:48 am

jza80king, Thanks again for the tips. I have done the Seafoam treatment a couple times now, just noticed the airfilter was really bad, a dirty old K&N, with no oil in it, will replace! I am sorry what is the AFM? Air flow meter? The car is running really smooth, so I dont think there is any misfire. Should I replace plugs, wires, cap, rotor anyway?

My question for today is, does the exhaust manifold cover play any role in keeping the exhaust gasses at the right temperature for the catalytic conversion to occur? My car had a header on it when I bought it and have since replaced it with the stock manifold and pre-cat assembly. However, I do not have the exhaust manifold cover. Is it a purely cosmetic piece, or is it needed for reliable emmissions performance? Thanks.

Next question, does anybody want to seel their stock exhaust manifold cover?

Post by **dad240sx** » Wed May 06, 2015 10:50 am

*sell

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