car failed TX emissions.

[TheOne]

car is 93 240sx, replaced head about 3 months ago, car had passed before this with same ebay intake(aiv disconnected but still in).

pollutant hi-speed emission(25mph) low speed emission(15mph)

HC(PPM) std: 132 mine: 17 std: 136 mine: 32CO(%) std: 0.73 mine: 0.09 std: 0.76 mine: 0.13NOx(ppm) std: 945 mine: 883 std: 1045 mine: 1720

ok, the car failed because the low speed NOx was high, everything else passed( and i mean everything).

i was told the cat and egr stuff could cause this, now what i've looked over the egr is that there is 2 disc like devices that have vacuum lines on the bottom(egr parts), where the intake manifold meets the firewall, the top disc has a vacuum line(at the bottom of the disc) that goes to somewhere in the intake(i believe).....well that line seems to be pinched(as in there's a 90 degree bend and its probably blocking the passage of whatever goes through that), could that have caused it to fail NOx?

(i have another intake manifold i could take parts from).

the cat and everything else passed last yr with good readings.

[91RMKS13]

TX has emissions?

I live in big spring texas a couple months ago my buddy took his honda del slow to get inspected the guy said hi asked if the lights worked then asked if everything else worked then gave the inspection sticker.

so where in texas do you live? and if i were you i would take your car to a small town (like big spring) and get it inspected.

[TheOne]

was your friends car a 96-97? if so then yeah those don't need to pass the sniffer test, those they just scan the ecu for codes and if none, pass safety test and be done.

in TX cars 96 and up only have to pass safety and check the ecu for codes, 95 and down have to go through the sniffer(till 25 yrs before date, thats when cars beome classics and only have to pass safety)

i can't seem to edit my info because the forum doesn't take â„¢ anymore lol so it keeps givin me an error, but i live in Arlington, TX and yeh i should find a small town to do the inspections.

[91RMKS13]

Its a 97. The guy didnt check a thing, he asked if everything worked fine and wrote out the sticker.

[Toshima]

I just go to lockhart about 25 min away from austin and get it done no emssions here in lockhart But austin has them.

[TheOne]

so anybody know why would i get high NOx?, could it be that line thats not allowin emissions to be cleaned well?

[InsanityInc]

It looks like either your EGR valve is a little funky, or you have a vacuum leak and are running lean.

[Nismo_Freak]

I just go to lockhart about 25 min away from austin and get it done no emssions here in lockhart But austin has them.

If you reside in Austin and you don't have the emissions inspection sticker you can be fined.

Just FYI.

[crzycav86]

Retard your base timing 4* or so, and run a seafoam treatment for good measure(if you haven't done so). It looks like you have a lot of room to spare in the HC and CO department.

[DjPantsSpecR]

Hey about that 90 degree bend hose you are talking about:

that thing sits at a stupid spot and either gets kinked or rubs on something and it must put a hole in the tube. Twice ive inspected this tube and found it to be kinked, but when i took it off, it had a massive hole in it. It is entirely possible this has something to do with your problem, as i believe this must be a common design issue.

[TheOne]

yeah i was thinkin that, i mean its pretty kinked in there, and as far as i know thats part of the EGR system which is supposed to raise the NOX.(along with a bad cat), so am gonna try fixing that, i'll also run some seafoam since i got new valve seals, headgasket and front/rear main seals.

if that doesn't work i'll check timing to see how it is, am not 100% sure its @ 20deg +-2

[Nismo_Freak]

Basically with NOX you just have to reduce the temperature of the combustion. Sometimes reducing the timing by a good amount doesn't work because the cat get's overheated. This is moreso an issue in S14's where the cat is located closer to the exhaust port.

[91RMKS13]

TX has emissions?

haha < never knew ^ before this post.

Edit: and i have lived there most of my life.

[Nismo_Freak]

Only the major cities have emissions.

DFW, SA, Austin, and Houston

[91RMKS13]

yea im from big spring texas (not so big) and you have to drive pretty far to get to a city of a decent size.

[TheOne]

well i found out the timing was advanced to like 25 degrees or so, guess thats what really raised the NOx, but i'll still check/clean the egr.

[TheOne]

hmmm....couple of months later, tested again and still NOx was high on same place, so am guessing either my cat is bad, or my egr stuff is worn out?, i checked & fixed the vacuum line, and still got the same reading.

(yes i know, revivin an old thread, but it was my thread!)

[Bigvinnie]

hmmm....couple of months later, tested again and still NOx was high on same place, so am guessing either my cat is bad, or my egr stuff is worn out?, i checked & fixed the vacuum line, and still got the same reading.

(yes i know, revivin an old thread, but it was my thread!)

Well since Cali emissions are much stricter I guess I'll help you out( I live in cali so getting you to pass Texas emissions should be a breeze. If infact it was the CAT that was out your engine would also show higher levels than normal in HC an in CO. A defective CAT would basically allow for all contaminents to travel through the pipe and the sniffer would defenitely pick it up. If infact you have disconnected the AIV it can infact increase NOX and prevent your catylitic converter from functioning to full capabilities correctly. The AIV is used to heat the cat to actually lower the NOX level so that could also be your problem, and more than likely it is, (since the AIV is used to dump clean air into the exhaust system). It could also be running lean which can infact cause NOX levels to run higher. So you would infact want to check your TPS and make shure that it is positioned correctly. Or a chance is that it could be your EGR/BPT system malfunctioning if that was the case your ecu would throw a system code 32 and that is still to be determined if you have a California ECU and not a federal ecu. (ecu's vary from state to state.) More than likely your engine light would also come on.Third check all vacuum lines and make shure that there are no burnt holes in the line between the EGR/BPT, or around any of the vacuum lines that lead to the purge canister. So reconnect the aiv and get back to us kkkk.

[JesusLikesKFC]

werd. went through this a while back when i first got my car. mine had gas in it. cat was crap( saw no light threw it), was a mess. got junkyard parts to replace it, was better but not what i needed so i ditched it all. just throw the guy 20 bucks.

[TheOne]

well i just checked my new emissions paper and am down quite some

NOx std: 1045 mine: 1323 (15mph test, believe 2nd gear @ 1700rpm)down from 1720 of last test.(believe this was cause of advanced timing + the pinched vacuum line)

i had an another engine in the car(rod knock cause of low oil pressure @ 6k rpm), with another intake manifold than it is in right now, same intake/AIV setup(AIV is not connected to the intake, but still mostly intact cept that it has a breather on it) and it had passed with flyin' colors....so i don't really think its the AIV, am starting to lean more into the EGR stuff in this intake manifold.

[miked808]

I had the same problem once. It turned out to be a MAF problem or IAT sensor. You wouldn't get a Check Engine Light either.

[boznuttz]

bad egr equipment. egr recurculates exhaust gas in order to lower the combustion temperature. o2 sensors deals with unburnt gas after runnign too lean