Help! What the hell could have happened? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

CELA · 10-24-2010, 10:04 PM

alright, so i've been looking online for all of the things that could have gone wrong. And I am still confused.
First time I smogged I passed everything except for the NO at 15mph.
As seen here:

So I get my car diagnosed at a different place cause it was cheaper, tells me that the theres a slow response from o2 sensor and poor efficiency from catalytic converter. So I try to save some cash and just swap the o2 sensor first maybe i wont have to put up the cash for the cat.
I change the o2 sensor, and reset my ecu, (but i was told that i didn't let it sit idle for long enough.)
As I drive the check engine light stays on, but eventually disappears. When I get some free time I head to the smog station, the light turns on again, and then goes away before I get there. I get tested, and the results are worse than before!
here they are:

The only thing I changed was the o2 sensor? Could the cat have gone that bad that quick? I'm thinking maybe I didn't reset correctly? Any advice appreciated

s13silvia123 · 10-24-2010, 10:35 PM

change your motor oil. you just barely passed so just change your motor oil it helps by alot as well

drift freaq · 10-24-2010, 10:50 PM

have you checked all your vacuum lines to make sure none are leaking? I would suggest you clean out your AIV system. The simplest way to do that is to remove the intake tube right at the throttle body and while the engine is running you rev it and spray carb cleaner directly in. It will put out a ton of smoke out your tailpipe as it cleans the system. You should also heat your cat up before putting it on the dyno. That means running it a 2800 rpm for at least ten minutes.

If your cat is actually on the weak side you might have to replace it. Oh and putting in fresh spark plugs and cap and rotor help as well.
If you do all these things you should be able to pass. I have taken gross polluters and done this stuff and made them pass.

CELA · 10-25-2010, 03:03 PM

What could have caused the numbers to bump up that much for the second test? I mean all I did was change the o2 sensor.

10-24-2010, 10:04 PM	#1
CELA Join Date: Sep 2008 Location: sd Posts: 13 Trader Rating: (1) Feedback Score: 1 reviews	Help! What the hell could have happened? alright, so i've been looking online for all of the things that could have gone wrong. And I am still confused. First time I smogged I passed everything except for the NO at 15mph. As seen here: So I get my car diagnosed at a different place cause it was cheaper, tells me that the theres a slow response from o2 sensor and poor efficiency from catalytic converter. So I try to save some cash and just swap the o2 sensor first maybe i wont have to put up the cash for the cat. I change the o2 sensor, and reset my ecu, (but i was told that i didn't let it sit idle for long enough.) As I drive the check engine light stays on, but eventually disappears. When I get some free time I head to the smog station, the light turns on again, and then goes away before I get there. I get tested, and the results are worse than before! here they are: The only thing I changed was the o2 sensor? Could the cat have gone that bad that quick? I'm thinking maybe I didn't reset correctly? Any advice appreciated

10-24-2010, 10:35 PM	#2
s13silvia123 Post Whore! Join Date: May 2006 Location: where waldo is Age: 43 Posts: 3,267 Trader Rating: (16) Feedback Score: 16 reviews	change your motor oil. you just barely passed so just change your motor oil it helps by alot as well __________________ 18g and 20g turbo users click on me http://zilvia.net/f/tech-talk/261219-18g-20g-turbo-users.html

10-24-2010, 10:50 PM	#3
drift freaq R.I.P. Aya, always love Join Date: Nov 2001 Location: Los Feliz/Hollywood Posts: 18,564 Trader Rating: (215) Rides Gallery: drift freaq Feedback Score: 215 reviews	have you checked all your vacuum lines to make sure none are leaking? I would suggest you clean out your AIV system. The simplest way to do that is to remove the intake tube right at the throttle body and while the engine is running you rev it and spray carb cleaner directly in. It will put out a ton of smoke out your tailpipe as it cleans the system. You should also heat your cat up before putting it on the dyno. That means running it a 2800 rpm for at least ten minutes. If your cat is actually on the weak side you might have to replace it. Oh and putting in fresh spark plugs and cap and rotor help as well. If you do all these things you should be able to pass. I have taken gross polluters and done this stuff and made them pass. __________________ "Having a lot of tracks on a song is like putting stickers on a car to get more horsepower" New Video https://www.youtube.com/watch?v=uebV1OnbRsw Buy my mounts! http://zilvia.net/f/sale-items/51531...ns-mounts.html http://zilvia.net/f/tech-talk/317539...e-mouts-6.html

10-25-2010, 03:03 PM	#4
CELA Join Date: Sep 2008 Location: sd Posts: 13 Trader Rating: (1) Feedback Score: 1 reviews	What could have caused the numbers to bump up that much for the second test? I mean all I did was change the o2 sensor.