HiGH NOx smog test need any help to pass!!

[dennydizzo]

i have a 1993 nissan 240sx w/stock ka24de..
well i waited for the last day of my driving permit to smog my car and i failed..i smogged my car after driving on the freeway 10 minz and left it running before it was tested so my cat would warm up and work correctly..my results are:

15mph
HC.....Max=88......Measured=57
CO.....Max=0.52...Measured=0.01
NOx...Max=704....Measured=3151
25mph
HC.....Max=53......Measured=28
CO.....Max=0.50...Measured=0.01
NOx...Max=738....Measured=1796

as you can see i failed the NOx with SUPER HIGH numbers..MY NOx is extremely HIGH compared to the other people wtf is up..my CO is really low..is that unusual? is it true about retarding the spark timing will lower nox?

my car drives like a champ with smooth idle at 850rpm

last 8 months replaced,
sparkplug wires,sparkplugs (except in 1st cylinder couldnt get the sucker out,
will not gaping the sparkplugs correctly be an issue?)
oil changed..
87 cheap gas pumped
knockoff muffler
egr is functional and car dies when you block off the bottom with your hand?
no leaks from cataylic converter bought from
a '90 240sx with low supposely low miles

what the FEEZY could be making my car NOx to skyrocket? any help will be greatly appreciated!!need to pass smog ASAP im in CA btw so smog is really really strict here..NEED ANY ADVICE..i dont have tons of cash available currently so i cannot take it to a mechanic so im trying to figure this out on my own!PLEASE HELP!

[wickedjester]

i

87 cheap gas pumped




What does that even mean?


and look here
http://zilvia.net/f/tech-talk/246318-smog-techs-need-your-help-nox-super-high.html

[dennydizzo]

What does that even mean?


and look here
http://zilvia.net/f/tech-talk/246318-smog-techs-need-your-help-nox-super-high.html


ive read that using different octane gasoline will have difference results??
trust me i've been reading tons and tons of treads about smog and the only thing i find to be consistent to NOx levels are the CAT and EGR so im checking those things out this week..i just thought my NOx levels are unusually HIGH others that fail are in the 800-1000 mines are 1700-3000 so im seein if anyone had somewhat same levels as mines..

[krissynbeau]

I just had the same problem. I had the egr line cleaned out and had to buy a new cat. I just passed yesterday

[SoguRacing]

if your nox is high, you either have.. carbon build up in your combustion chambers causing your effective compression to increase causing higher combustion temps which cause NoX to form above 2500 degree's F. Your other numbers look ok. if you really want to try something out. put a bottle of 90% osoproply alcohol into your gas tank and that will lower your NoX emissions. it varies by car. give it a try. Make sure your timing is correct. clean your maf sensor. could be causing a false reading causing your car to run slightly lean and still within range of passing. also check to see if your o2 sensor is functioning properly. an o2 sensor to ensure proper functionality.

[dennydizzo]

im most likely cleanning out my egr and going to get a new cat so we'll see from there.. my timing is at 20btdc and maf has only 3 pins is that correct?

[BlazedGlory]

I'd check your EGR system to make sure it is working properly first... and not clogged. Don't touch the cat at this point...

[w0nderbr3ad]

check the vacuum hoses leading from the egr to bpt valve. theres a 90* bend vaccuum hose that usually gets eaten up. My nox read about 4000 when I did smog and I fixed that and ran fine. Check all the other vacuum lines behind the head as well.

[ryguy]

check the vacuum hoses leading from the egr to bpt valve. theres a 90* bend vaccuum hose that usually gets eaten up. My nox read about 4000 when I did smog and I fixed that and ran fine. Check all the other vacuum lines behind the head as well.

I promise it's your EGR-BPT valve, or the vacuum lines running up to it. You can just bypass it to pass the sniffer test, then hook it back up when you're done. You'll run a tad rough with it bypassed, but it'll pass with flying colors.

[haggard240]

damn california sucks.. we don't have any of that stuff in ohio.

[Fonzs13]

you could get a new cat...then run the car with 91 octane it will lower the nox...then there are the egr solenoids on the back of the motor near the firewall check those out....mine was failing smog for the same thing...but i bought a cat and i ran the car but i still failed at 15mph and 25mph...what i found out is that my nox would only lower down at 16 and a half miles per hour to literally below 100 on nox readings...which kinda sucked since the test is only at 15mph..so you could get a smog shop to diagnose your car then tell them to check to see if the nox drops down at 16 and a half miles per hour....thats how mine passed i had to smog it on first gear....good luck!!

[dennydizzo]

finally got time to checkk my ecu codes and the only thing that came up was

34-detonation(knock sensor)

i checked the wires and everything looked fine..
i read up and found that a clogged egr may make me get a
knock sensor code to come up?anyone know about this?

next step getting my egr cleaned out and checked for leaks..

[S-Nation S13]

lol jus changed the whole egr system thats what i did
EGR valve,BPT,the little 90 degree hose,egr solenoid and clean out the metal egr pipe,o and slap a new 02 youll pass for sure...
you knock sensor..mostly likely your gonna have to get a new one as well !!

[surreybc]

finally got time to checkk my ecu codes and the only thing that came up was

34-detonation(knock sensor)

i checked the wires and everything looked fine..
i read up and found that a clogged egr may make me get a
knock sensor code to come up?anyone know about this?

next step getting my egr cleaned out and checked for leaks..

egr is there to cool things down to prevent explosions so yeah bad egr could trigger knock sensor code.

[BlazedGlory]

lol jus changed the whole egr system thats what i did
EGR valve,BPT,the little 90 degree hose,egr solenoid and clean out the metal egr pipe,o and slap a new 02 youll pass for sure...
you knock sensor..mostly likely your gonna have to get a new one as well !!

You - wrong, Surrey - right

[S-Nation S13]

You - wrong, Surrey - right


my bad lol so tell me why i passed live by the sword die by the sword smog is no joke why go half-ass when your gonna have to go through it every 2 years??? UNLESS your COOL and get one under the table

[S-Nation S13]

egr is there to cool things down to prevent explosions so yeah bad egr could trigger knock sensor code.

egr has nothing to do with knock sensor

knock sensor's main function is to warn you that your car is detonating to early which cause engine malfunction knocking sounds means your car is detonating as you cylinder is raising up to complete combustion if anything you throwing knock sensor code your to far advance

[surreybc]

egr has nothing to do with knock sensor

knock sensor's main function is to warn you that your car is detonating to early which cause engine malfunction knocking sounds means your car is detonating as you cylinder is raising up to complete combustion if anything you throwing knock sensor code your to far advance

get a lobotomy

[BlazedGlory]

my bad lol so tell me why i passed live by the sword die by the sword smog is no joke why go half-ass when your gonna have to go through it every 2 years??? UNLESS your COOL and get one under the table

You passed because you wasted all kinds of money fixing things that weren't broken, and you happened to fix the problem in the process. You are spreading misinformation.

[BlazedGlory]

egr has nothing to do with knock sensor

knock sensor's main function is to warn you that your car is detonating to early which cause engine malfunction knocking sounds means your car is detonating as you cylinder is raising up to complete combustion if anything you throwing knock sensor code your to far advance

EGR has everything to do with the knock sensor. The only reason EGR systems are in place is to lower combustion temperatures, which lowers oxide of nitrogen emissions and, gasp, detonation. I won't waste my time explaining it. Do some research and quit spreading misinformation.

[S-Nation S13]

please close this thread to much ego!!!! now-a-days i guess readin online info automatically means your ASE certified and its not wastin money when its throwin MIL unless your to broke to fix it

[BlazedGlory]

It is wasting money when you fix things that aren't broken. That is like replacing your engine instead of changing the oil. I personally choose to change my oil because I don't like wasting money, not because I'm too broke to buy a new engine every 3-5000 miles.

And it is funny that you mentioned ASE because I am actually a Master certified ASE Automotive mechanic with L1 (Advanced Engine Performance) ASE as well (not required for Master status). I am also a Senior Certified Lexus mechanic, and I will have my Master Lexus certification in about 5-6 months.

I do agree though, close this thread because the misinformation will not end until it is closed. No ego, just trying to help stop misinformation on the internet when I see it.

[S-Nation S13]

It is wasting money when you fix things that aren't broken.

some call it wasting ...some call it investment MR. ASE you out of all people should know cars will break,parts will fail!!! why fix one when they all work together as a whole

No ego, just trying to help stop misinformation on the internet when I see it. ok well if you here to stop mis-information than, like in true zilvia nature do a search...


http://www.partstrain.com/ShopByDepartment/Knock_Sensor (http://www.partstrain.com/ShopByDepartment/Knock_Sensor)
"By simply performing its function, the knock sensor does two things for your vehicle's engine: (1) it allows optimum engine performance and (2) it protects the engine from potential damages caused by detonation. And because nearly all stock knock sensors used on vehicles today are dependable, you may not find a need to replace them for the life of your vehicle. Acts of carelessness, however, may cause the knock sensor to get damaged. Running the vehicle using fuel with much higher volatility or much lower octane ratings than what is recommended by the vehicle manufacturer are among those things that may cause knock sensor failure."

"Many factors can cause such detonations. Among them are too much carbon deposits on the cylinders, spark plugs that are too hot for the engine, high combustion chamber temperatures, and too advanced spark timing."

Many factors lol not EGR has everything to do with the knock sensor

can be related to the egr..but more than less its main funtion is to protect engine from detonation error due to timing issues

http://www.partstrain.com/ShopByDepartment/EGR_Valve (http://www.partstrain.com/ShopByDepartment/EGR_Valve)
The primary function of this part is to send some of the exhaust gas through the intake manifold back into the cylinders in order to lower the combustion temperature.

so if egr primary function is to do this.. its safe to say that egr/knock sensor failure more than less are 2 seprate part failures rather than part failure do to other parts...unless timing and basic engine function is an issue

DENNYDIZZO you want a fix well here it is...

my car drives like a champ with smooth idle at 850rpm

s13 FSM states idle with no load is 700 +/- 50 rpm which puts you at a minimum of 650 rpm or a maximum of 750rpm ..not 850 rpm fix that first..
1.check timing 20 degree +/- 2 degree
2.idle speed 700 +/- 50 rpm

you can quote me on that "BLAZEDGLORY" aka MR. ASE


egr is functional and car dies when you block off the bottom with your hand?

that means your egr valve works but the valve is controlled by EGR BPT VALVE the other UFO looking thing above your egr valve which is controlled by vac
you can quote me on that "BLAZEDGLORY" aka MR. ASE

And it is funny that you mentioned ASE because I am actually a Master certified ASE Automotive mechanic with L1 (Advanced Engine Performance) ASE as well (not required for Master status). I am also a Senior Certified Lexus mechanic, and I will have my Master Lexus certification in about 5-6 months.

...and im the president of the united states..lol now-a-days the internet is all hear say i personally dont know you ,so i really dont believe you... senior tech for LEXUS this is aNISSAN engine 5-6 months of working on TOYOTA motors "lets just say you forgot a lil"

a '90 240sx with low supposely low miles its a used car, do you persoanlly know the previous owner?? driving habits?? did they to all the maintenence?? ...HIGHLY DOUBT IT but maybe you do


IM NOT ASE CERTIFIED I DONT HAVE A MASTER ..but what i do have is common sense and the knowlegde to fix problems, the knowledge that some ASE/MASTER techs lose cause there all hyped up cause they passed some test and got a flimsy @ss certificate..to be honest i know car guys that can fix cars better than are so called reliable auto-technicians and dont have certificates!!! blazedglory just to let you know auto-technology/engine perfomance was my major but i dont flaunt it !!!!

DO WORK BEFOR TRYING TO SAVE THE FORUM WITH MISINFORMATION when you yourself miss the key points. Read into the information given sometimes youll already know what to fix !!!
blazedglory you fail :rl: EPICALLY!!!!

[BlazedGlory]

some call it wasting ...some call it investment MR. ASE you out of all people should know cars will break,parts will fail!!! why fix one when they all work together as a whole


Cars will break, parts will fail. Replace them when they fail. Again, don't replace your engine because you need new oil in it. Sure, it all works together as a whole, but I personally would rather just replace the oil. I guess just my personal preference. The only time I recommend buying extra parts is when I'm already far into an engine and it will save a lot of money in the future. For example. If I do a timing belt, I recommend replacing cam/crank seals and water pump instead of charging another 7 hours later if those items fail before the next 90000 miles.


"By simply performing its function, the knock sensor does two things for your vehicle's engine: (1) it allows optimum engine performance and (2) it protects the engine from potential damages caused by detonation. And because nearly all stock knock sensors used on vehicles today are dependable, you may not find a need to replace them for the life of your vehicle. Acts of carelessness, however, may cause the knock sensor to get damaged. Running the vehicle using fuel with much higher volatility or much lower octane ratings than what is recommended by the vehicle manufacturer are among those things that may cause knock sensor failure."

"Many factors can cause such detonations. Among them are too much carbon deposits on the cylinders, spark plugs that are too hot for the engine, high combustion chamber temperatures, and too advanced spark timing."

Many factors lol not

can be related to the egr..but more than less its main funtion is to protect engine from detonation error due to timing issues


so if egr primary function is to do this.. its safe to say that egr/knock sensor failure more than less are 2 seprate part failures rather than part failure do to other parts...unless timing and basic engine function is an issue



You said it all right here, but I'm not sure that you put it all together. I agree that they are two different systems, but even you said detonation can be caused by high combustion chamber temperatures. I agree. EGR lowers combustion chamber temperatures. We all agree. Therefore, it is possible that a non functional EGR system will cause detonation and cause the knock sensor to behave how the ECU might determine erratic (I'm not sure what the parameters are on the KA knock sensor code). I agree with you completely. I'm not sure if you realize you agree with me though.


IM NOT ASE CERTIFIED I DONT HAVE A MASTER ..but what i do have is common sense and the knowlegde to fix problems, the knowledge that some ASE/MASTER techs lose cause there all hyped up cause they passed some test and got a flimsy @ss certificate..to be honest i know car guys that can fix cars better than are so called reliable auto-technicians and dont have certificates!!! blazedglory just to let you know auto-technology/engine perfomance was my major but i dont flaunt it !!!!

[/SIZE]

The only reason I let you know about my ASEs is because you seem to hold them in such high regard. And I'll quote:

please close this thread to much ego!!!! now-a-days i guess readin online info automatically means your ASE certified and its not wastin money when its throwin MIL unless your to broke to fix it

You brought it up, not me.

[BlazedGlory]

I just remembered (I guess you distracted me lol) that the whole disagreement began because you said this man needs a knock sensor because his NOx levels are too high, which is still incorrect.

Please pm me so we don't clutter his thread if you wish to discuss anything further.

[S-Nation S13]

I just remembered (I guess you distracted me lol) that the whole disagreement began because you said this man needs a knock sensor because his NOx levels are too high, which is still incorrect.


please your wasting my time and cluttering this thread.. where did i say that...lol and no i havent edited to hide my mistake but i clearly havent made one but i asure you i havent said this EPIC fail of advice ..he said he was throwing knock code..lol i said

lol jus changed the whole egr system thats what i did
EGR valve,BPT,the little 90 degree hose,egr solenoid and clean out the metal egr pipe,o and slap a new 02 youll pass for sure...
you knock sensor..mostly likely your gonna have to get a new one as well !!

my ADVICE was just replace egr system also knock sensor..throwing code ..just fix the part thats how i think..AGAIN PLEASE READ MORE INTO THE INFO GIVEN RATHER THAN PUTTING WORDS IN MY MOUTH!! THIS STARTED CAUSE YOU BELIEVE I SAID GET A NEW KNOCK SENSOR CAUSE YOUR NOX IS HIGH :cj:

AGAIN MODS PLEASE CLOSE THIS THREAD DUE TO THE FACT THAT SOME PEOPLE MISREAD INFO AND CLAIM TO BE HELPING OUT STOP MISINFORMATION BUT IN FACT CAUSE MORE CONFUSION WHILE IN THE PROCESS...(DENNYDIZZO) if you dont wanna replace parts my last post should get you stared into finding your fix.. dont believe me here read this http://www.240edge.com/manuals/s13-ka24de.html (http://www.240edge.com/manuals/s13-ka24de.html)
thats the fsm to your car ive read most of it and i have given you advice off of this!!
HINT: BLAZEDGLORY..read this befor puttin your 2 cents in NISSAN INFO IS GOOD FOR YOU

I HAVENT EDITED ANYTHING CLEARLY I HAVENT SAID WHAT THIS ASE/MASTER TECH HAS ACCUSED ME OF..PRIME EXAMPLE OF HOW THESE SO CALLED RELIABLE TECHNICIANS GET CAUGHT UP IN THERE ABOVE LEVEL OF KNOWLEDGE..CAUSE THEY GOT SOME FLIMSY @SS PAPER THAT STATES THAT THERE CERTIFIED


ONCE AGAIN BLAZEDGLORY YOU FAILED EPICALLY putting words in my mouth!!!:l101:

[BlazedGlory]

I'll take it to pm to end the show then. *Puts arm around S-Nation to sway him with me to PM*

Thanks

[dennydizzo]

reset the code and driven the car for a couple of miles and no codes popped up yet so hopefully the knock sensor is not a problem..checked my timing and its at 20btdc..going over my emission numbers i noticed my CO is at 0.01 at both speeds can anyone tell me what that would mean? slow o2 sensor? running super lean??

[S-Nation S13]

you CO seems fine your passing!! do you know how to test your o2 sensor?? look at the FSM link it shows you step by step on how to test it

[BlazedGlory]

Is the timing not supposed to be 15*BTDC?

[S-Nation S13]

nope as per FSM timing is 20' btdc with +/- 2' look on page 29 under the EF & EC

[dennydizzo]

ok so instead of taking out my egr and cleaning it i got another catalytic converter and hooked it to my car and took it to a smog shop(a no pass no pay place) to see how the new numbers will look...turns out i still failed due to high nox at both speeds only went down about 200..

so after avoiding removing and cleaning my egr looks like i have to..and ive read that retarding the timing will reduce NOx numbers..this is correct? and how much can i lower it without damage..

[BlazedGlory]

Sorry to be a smartass, buy why ask for help if you don't want to hear any solutions? I still say check out the EGR system. It may not be that the valve itself is clogged, it may just not be operating at all. Who knows. That would still be the best place to start unless you want to keep throwing parts at the problem. If it is all good, at least that will be eliminated from the very good possibility list.

[dennydizzo]

Sorry to be a smartass, buy why ask for help if you don't want to hear any solutions? I still say check out the EGR system. It may not be that the valve itself is clogged, it may just not be operating at all. Who knows. That would still be the best place to start unless you want to keep throwing parts at the problem. If it is all good, at least that will be eliminated from the very good possibility list.


oh no doubt im going to take apart my egr..i just wanted to rule out the catalytic since its easier to remove than the egr..but now im just wondering if retarding the timing will help me out lowering the NOx level along with cleaning or replacing the egr..

[BustedS13]

when my state still had emissions testing, i once unplugged an injector and let them run it on three cylinders to pass with flying colors.

[dennydizzo]

when my state still had emissions testing, i once unplugged an injector and let them run it on three cylinders to pass with flying colors.


r u serious?will that actually work?

[BustedS13]

r u serious?will that actually work?

it worked for me.

[dennydizzo]

okay so i ended up taking apart my egr and cleaned the hell outta it..it was filled with alot of black carbon crap and i ended up buying a brand spanking new catalytic converter and changed my o2 sensor..my results were:

15mph
HC.....max=88.....measured 30
cO.....max=0.52...measured 0.03
NO.....max=704....measured 27

25mph
HC.....max=53.....measured 16
CO.....max=0.50...measured 0.04
NO.....max=738....measured 5

finally passed with Flyin colors...thanks everyone for their suggestions and output!! :bigok:

[S-Nation S13]

lol thats whats up ..but i think you could of passed with out the new cat but anyways its something that you dont have to replace down the road..hehe

[BlazedGlory]

Agreed =P. Well, he'll have to replace it down the road when it fails again =P

[dennydizzo]

Agreed =P. Well, he'll have to replace it down the road when it fails again =P

:mepoke:iF...iF it fails!!

[BlazedGlory]

=P All I'm saying is if you had to replace it once you will have to again. Everything fails at some point. That is why I'm so gungho about diagnosing problems. If you replace something that hasn't yet failed you miss out on some of its usable life and the new part will fail at some point as well.

[handinpants]

Your nox levels are high because something in your setup is causing it to run lean and therefore increasing the combustion temps, also you want to fill up 91 octane, maybe buy a new cat and clean the egr, or you can write down the cost for all this, and compare it to paying for a dirty smog and go for the cheaper of the two.

But I recommend you go the legal route

[Seikenman]

Congrats on passing your emissions test. About your knock sensor code. You were getting it because you were running 87 regular gas. The dohc 240's need to run 91. You can run 87 but the sensor will detect knock, throwing the knock code, and retard the timing

[BustedS13]

ha ha ha. i capped off my EGR with a chunk of license plate, and i'm about to get an exhaust fabbed up from the header back with no cat.

god i love not dealing with bullshit

[miklos]

Timing at 15 is the factory setting

[modulation]

I'd bet you had a pre-cat exhaust leak.
I had similar problems (really high nox, low hydrocarbons.)

Turned out to be a exhaust leak right before my cat.

[miklos]

I pulled out my egr after running seafoam through the throttle body and found carbon caked inside the manifold.
My egr solenoid had no ground and the vacuum hoses were melted back there on an SOHC.

[miklos]

I just failed for the 3rd time.
After the 2nd time:
I replaced the spark plugs and plug wires, O2, EGR solenoid, cleaned out the EGR ports, 2 new fuel injectors, new vacuum hoses, and the MAF.

15mph NOX 2803
25mph NOX 1276
15mph CO .87

Do you think a new cat would fix all of this?

[s13silvia123]

change your motor oil helps reduce nox. new oil helps the motor work less and creates less nox.

where i use to live use to have smogging and i failed on NOX so i changed my motor oil and went back and passed with flying colors.

[miklos]

Oil was changed 5 weeks ago. I'm sure the Cat must be bad causing the NOx to be high

[DreamN]

Are you getting any codes at all? How's your idle?

Typically when a cat is bad all three areas are higher than normal.

[miklos]

I was getting a code for the EGR temp sensor but the light has been off for a week. Idle is good.

http://thechive.com/wp-content/uploads/2009/04/hysterical-motivational-poster-16.jpg

[NismOkatFreaK]

Damn smog suck's, I kept failing so I figured it had to be the air idle control valve or whatever that things called that everyone takes out. So I took the pipe off that attaches to the exhaust, put a nickle in there then reattached the pipe and walla, I passed! Just thought id share what I had to do.

[DreamN]

You blocked off the EGR pipe? lol

[240trooper]

my 240 years ago didnt pass for shit. found out the cat was gutted lol . New cat and had teh egr replaced and it passed. failed was GP over 3000's , passed in the 110's

[miklos]

Damn smog suck's, I kept failing so I figured it had to be the air idle control valve or whatever that things called that everyone takes out. So I took the pipe off that attaches to the exhaust, put a nickle in there then reattached the pipe and walla, I passed! Just thought id share what I had to do.
You mean the hose at the bottom of the AIV going to the exhaust?

[Almedarj]

i gotta friend who will just pass your car even if you failed already but it cost about $300 not bad considering you might pay to get what you thought was the issue fixxed and have your car fail again lol

[ILLES13]

I just had the same problem. I had the egr line cleaned out and had to buy a new cat. I just passed yesterday


Same here, i have the same year same motor coupe. also hit NOX in the 3000's.
bought a brand new catalytics converter, passed it like a champ

[miklos]

I know a new cat will make the car pass.......but Gold Shield gives them out last after they do everything else. And since I'm running rich---the cat would go out in 3 months.........so I might as well fix the richness and stop wasting gas.

[thelrgkid]

Anyone know where i can get the setup of the vacume lines behind the engine by the firewall?

[BlazedGlory]

In the FSM. What engine?

[bonezdebomb]

my dad drives a 98 frontier and every time he puts cheaps gas in it the o2 sensor flips out. you might want to change that out if your going to do the cat