bored smog tech here

[soreballz]

Originally Posted by techn9ne

does she have heinous 3" exhaust? (the car) is the backpressure valve working correctly? is the pulse air hooked up? what test is it failing for?

2.5" exhaust.
Wtf is a "backpressure valve"? Do you mean EGR?
Pulse air is hooked up, not that it would make any difference. The only function of the the pulse air valve is to pre-heat the cat so the car will run "cleaner" before the engine is fully warmed. Since the tests were all done while the car was hot, the PAIR valve wouldn't have made a shit of a difference.

Its failing a regular test-only... 30 mph test, iirc.

Are you sure you're really a smog tech? lol

[techn9ne]

Originally Posted by soreballz

2.5" exhaust.
Wtf is a "backpressure valve"? Do you mean EGR?
Pulse air is hooked up, not that it would make any difference. The only function of the the pulse air valve is to pre-heat the cat so the car will run "cleaner" before the engine is fully warmed. Since the tests were all done while the car was hot, the PAIR valve wouldn't have made a shit of a difference.

Its failing a regular test-only... 30 mph test, iirc.

Are you sure you're really a smog tech? lol

actually
the purpose of the pair valve is to act as an afterburner during idle and continue the burn of exhaust gasses after they leave the cylinder. the backpressure valve is connected to the exhaust and controls the vacuum going to the egr. if the exhaust is a larger diameter, there wont be enough backpressure going to the valve. since the valve doesnt have sufficient backpressure, it doesnt work correctly, therefore, the egr valve doesnt work correctly.

[techn9ne]

Originally Posted by flclsteve

Mr smog tech.
I have a 97 honda civic witch just got approved for assistance with smog repair fees it failed for high Nox during the 15 mile per hour run
any idea what it might be its a bone stock car

what motor?

[blackrms13]

I know this is a old thread but I just failed my smog

91 S13(about 115k) with a stock 95 OBD-I KA(68k), I believe it is a non-cali engine

New Plugs/Wires (about year ago)
New O2 Sensor (2-3 weeks ago, but the tech said "something is wrong with it b/c its running very rich)
2.5inch catback

NO reading is like 7xx max right?
I got like 3000+ reading...

i warmed up my car pretty well before doing the smog(drove from riverside to LA, about 1 hour)

I know the timing is off for sure(well after the test....) need to find a timing light first
gas cap failed(bought a new one right afterwards)

from reading this thread, i assume its time for a new cat?

thanks to whoever can help

[MrChow]

^^ Yup sounds right your cat. I've the sniffer with my timing being at 10...

[blackrms13]

which pin should i set it to?
from this pic i saw, the one on the far right, correct?
when i set the timing, should i look at from the top, or from more like a 45 degree angle

[SochBAT]

Whats the difference between Test Only and normal Smog shops?

Is test only for 'older' cars?

[blackrms13]

from my research, I think test-only place is selected for the more-likely-to-be-gross-polluter cars and such places only do test, no repair

[SochBAT]

I think that too, but I wanted confirmation. More Researching!

[MrChow]

Originally Posted by blackrms13

which pin should i set it to?
from this pic i saw, the one on the far right, correct?
when i set the timing, should i look at from the top, or from more like a 45 degree angle

It should be 20 TDC

Timing

[blackrms13]

Originally Posted by MrChow

It should be 20 TDC

Timing

thx I have figured out the timing...at least i think i did

i continued my problems here

http://zilvia.net/f/tech-talk/223732-smog-problems.html

[SoguRacing]

Originally Posted by blackrms13

I know this is a old thread but I just failed my smog

91 S13(about 115k) with a stock 95 OBD-I KA(68k), I believe it is a non-cali engine

New Plugs/Wires (about year ago)
New O2 Sensor (2-3 weeks ago, but the tech said "something is wrong with it b/c its running very rich)
2.5inch catback

NO reading is like 7xx max right?
I got like 3000+ reading...

i warmed up my car pretty well before doing the smog(drove from riverside to LA, about 1 hour)

I know the timing is off for sure(well after the test....) need to find a timing light first
gas cap failed(bought a new one right afterwards)

from reading this thread, i assume its time for a new cat?

thanks to whoever can help

if your NOX reading is high then you're running lean not rich. NOX is the production of excess heat in the combustion chamber. a lean condition will cause the NOX number to be excessively high. If all your other numbers were fine, it's not the cat. Try retarding your timing a bit or getting a step colder plugs. this may help.

[touge monster]

Originally Posted by Soooshi

Whats the difference between Test Only and normal Smog shops?

Is test only for 'older' cars?

Correct me if I'm wrong, but they are both the same as far as testing goes.

A test only shop can only test and do nothing else, whereas in a regular smog shops, the techs can make adjustments to your car and replace parts to make it pass.

I think test only are only for older cars.

[touge monster]

Originally Posted by SoguRacing

if your NOX reading is high then you're running lean not rich. NOX is the production of excess heat in the combustion chamber. a lean condition will cause the NOX number to be excessively high. If all your other numbers were fine, it's not the cat. Try retarding your timing a bit or getting a step colder plugs. this may help.

Had the same problem.

new plugs and re-adjusting your timing should make it pass.

[GSXRJJordan]

Originally Posted by touge monster

Correct me if I'm wrong, but they are both the same as far as testing goes.

A test only shop can only test and do nothing else, whereas in a regular smog shops, the techs can make adjustments to your car and replace parts to make it pass.

I think test only are only for older cars.

That's correct.

The TEST ONLY shops are supposed to be "stricter", more like a Ref. The 'regular' smog test guys can repair your car, and "work with you" to get it passed... test only just runs the test, and if you don't pass any single part, get-outta-here.

So lets see how to put this... if you are in a situation where your car for sure won't pass smog, but you don't have to go to Test Only, you can always take it to a "regular" test place and see if they'll work with you. If you have to get it done at a Test Only (the registration/DMV paperwork will tell you at the top in bold), you're probably going to have to buy a smog, and it might be more expensive because Test Only is watched much more closely.

[touge monster]

California's smog law suck.

[blackrms13]

Originally Posted by SoguRacing

if your NOX reading is high then you're running lean not rich. NOX is the production of excess heat in the combustion chamber. a lean condition will cause the NOX number to be excessively high. If all your other numbers were fine, it's not the cat. Try retarding your timing a bit or getting a step colder plugs. this may help.

the guy who previously had my engine said he put in some new Iridium(sp?) plugs a few months ago

should i switch back to the normal Copper ones?

thanks


heres more info regarding my problem
http://zilvia.net/f/tech-talk/223732-smog-problems.html

[idlafie]

Originally Posted by SoguRacing

if your NOX reading is high then you're running lean not rich. NOX is the production of excess heat in the combustion chamber. a lean condition will cause the NOX number to be excessively high. If all your other numbers were fine, it's not the cat. Try retarding your timing a bit or getting a step colder plugs. this may help.

High NOX readings is the result of your Exhaust Gas Recirculation, (EGR) system not working. You could have a cut, melted or split vacuum line or bad soleniod somewhere in the EGR system...You'll need a Factory Service Manual to trace the lines & fix the problem.

The purpose of EGR (Exhaust Gas Recirculation) is to reduce the NOx emissions by putting a portion of the vehicle's exhaust gas back into the intake manifold so it mixes with the fuel and air in the combustion chamber. Air is mainly made of oxygen and nitrogen (O2 and N2). At temperatures above 1300°C (2372°F), these molecules split apart and rejoin with each other to make nitrogen oxides (like NO, NO2, etc...).

By adding hot exhaust gases into the combustion chamber, you are lowering peak combustion temperatures. The lower temperatures prevent the O2 and N2 from splitting and combining. Even though the exhaust is hot, about 600°C (or 1112°F), it's much cooler than the 1300°C required to make NOx.

In summary, the exhaust adds mass, increasing the heat capacitance of the mixture (i.e. making it harder to heat up the mixture in the cylinder). Peak temperatures are lower, reducing NOx formation, which ultimately reduces smog in the environment.

[EwokVillage]

Originally Posted by techn9ne

ask me questions if you need to know something. its dead at my work, and im getting paid to browse zilvia.

smog questions here:
just got a 1996 240sx, automatic...it won't pass smog at 15 mph but passes at 25 mph. the MIL/Check Engine light part of the test also fails. the smog place i go to advised me that this is because the battery was disconnected at some point.

what can i do to get this thing done? my registration is coming up and i'm semi-FUBAR.

[DALAZ_68]

techn9ne - i have my 91 coupe i needa smog for insurance...problem being i have Engine light, code is for EGR (code 32) i know what it is, but i dont have time, ive been told that it can still pass sniffer even wiht this specific code on, but im just wondering if i can bring it to ur shop for smog and if theyll be linient on me wiht the E light on, cuz fuck me, getting to the egr under the manifold is abitch...fat fingures FTMFL

P.S. car is completely stock

[noneckgus]

so if i customized the stock air filter box would the nox levels be out of spec and cause the car to fail smog?

[lflkajfj12123]

Originally Posted by idlafie

High NOX readings is the result of your Exhaust Gas Recirculation, (EGR) system not working. You could have a cut, melted or split vacuum line or bad soleniod somewhere in the EGR system...You'll need a Factory Service Manual to trace the lines & fix the problem.

The purpose of EGR (Exhaust Gas Recirculation) is to reduce the NOx emissions by putting a portion of the vehicle's exhaust gas back into the intake manifold so it mixes with the fuel and air in the combustion chamber. Air is mainly made of oxygen and nitrogen (O2 and N2). At temperatures above 1300°C (2372°F), these molecules split apart and rejoin with each other to make nitrogen oxides (like NO, NO2, etc...).

By adding hot exhaust gases into the combustion chamber, you are lowering peak combustion temperatures. The lower temperatures prevent the O2 and N2 from splitting and combining. Even though the exhaust is hot, about 600°C (or 1112°F), it's much cooler than the 1300°C required to make NOx.

In summary, the exhaust adds mass, increasing the heat capacitance of the mixture (i.e. making it harder to heat up the mixture in the cylinder). Peak temperatures are lower, reducing NOx formation, which ultimately reduces smog in the environment.

thank you for explaining the point of the EGR system to me

never knew that

[dennydizzo]

cant pass smog!!need help! my results:

'93 240sx ka24de all stock except no resonator on stock intake
changed sparkplugs/wires
(except for cylinder #1 couldnt get the suckker out)
got a CAT from lower mile 240sx

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

recent oil changed
tested egr and car nearly died out when blocked the bottom..
warmed up car on freeway 10mins before test..

what should i do to extremely lower my NOx? should i clean out egr?does
gapping the sparkplugs important for smog? i think i seen i only had 3 pins on my maf is that normal?
any help i would i appreciate it thanks..

[miklos]

My Smog problem:

I went to Test Only and all Visual passed but my NO at 15mph was 3652 and at 25mph it was 3045. This was tested in California. My cat is 2 years old.

The odd thing is if I join the 2 vacuum lines going to the AIV--the car idles 100rpm higher and much smoother.

[zenki.life]

nice. you bumped an old ass thread that looks like the OP doesnt even post in anymore

[ho0dlumka13]

does anyone know if i can pass smog with 248/248 cams?

[miklos]

Originally Posted by zenki.life

nice. you bumped an old ass thread that looks like the OP doesnt even post in anymore

What is the problem posting in an old thread? It isn't closed.

[blackrms13]

Originally Posted by miklos

My Smog problem:

I went to Test Only and all Visual passed but my NO at 15mph was 3652 and at 25mph it was 3045. This was tested in California. My cat is 2 years old.

The odd thing is if I join the 2 vacuum lines going to the AIV--the car idles 100rpm higher and much smoother.

most likely ur EGR system is clogged

[chibo]

What does the OBD2 scanner actually read? Does it get actual RPM numbers or anything? Does it just check that the ECU sends READY for everything?

[NINJASPY]

Dear smog tech,
question 1. A friend is telling me they no longer do the "reffing" for swapped engines in cars, he was telling me they don't really care about sr20's etc anymore as long as you pass the sniffer/db test.

question 2. What would it take to pass a ls1 in a s14? The car would have two cats, two mufflers, and be quiet. It would also be running the stock ecu/pcm and all factory vacume lines will connected. Engine will also be newer than the chasis. Any other rules to get it to pass?