Hey all,

I was just wondering what I should look at first if my car (not my Subbie but my '93 Honda Prelude) doesn't pass smog.

More specifically I fail because of High NO and CO values during the 15mph test, I am fine at the 25mph test. New CA smog test = Dyno'ed runs.


I have an intake and an headers that are CARB exempt (DC sports). And I took off the Exhaust for the test.

I am thinking EGR valve / O2 sensor.

Anything else??

TIA!!

 

did you reset your ECU after you took off those exhaust parts? You might be running really rich.
I passed with my civic running a steep cam. but that was pre dyno.

 

If your car is now in stock form I would take it into the dealer. CA law stipulates that all smog equipment be covered for 5 years... I think. With high NOx I would reccomend replacing your O2 sensor and try running some feul injector cleaner through as well.

-Chris

 

High NOX is usually the EGR Valve.....

 

Why do you hafta smog an '03? CA law says 4 years or older :confused

 

resetting an ECU will invoke a richer condition.

 

cuz he made a typo and typed 03 instead of 93. It has been edited and u can see the original from the 1st reply in the thread.

 

Ah, so now he's just trying to make me look like an idiot? It's not that hard

 

Maybe your timing? I know of quite a few people who have had their Integra fail smog and it was just a timing issue. I forget what the result was on the smog test tho

 

Sorry had to edit... not '03 but '93

 

Thanks for everyone's responses, you fellow I-clubers are awesome!

After the responses you have confirmed my thoughts..

I think I'm going to change the o2 sensor first and then the EGR valve. Maybe then do a minor tuneup/ FI cleaner .


Hopfully after all that it'll pass smog..

Thanks again all

 

check your timing...make sure is rite....

get some injector and fuel systems clearner....

change the spark plugs... (it shouldnt cost that much)

check the cap and rotor...make sure is still good...

a lot of time because of carbon build up inside the combustion chamber will cause high NOX...

try those and get it pretest again ...

 

One of my brother's cars is a '91 non-Suby that wouldn't pass smog. A shop told him it was likely the catalytic converter. I told him that changing the O² sensor was a cheap possible fix if it wasn't the cat so he tried it. Still couldn't pass smog. He brought it to a shop who fitted a new higher flow (compared to OEM) converter and it passed smog with flying colors. He also says that apparently the OEM converter was so clogged that he immediately noticed that his car ran stronger after leaving the repair garage.

--
0==WW==0
"…axles of evil…" - george w. bush

 

with high NO makesure your timing isnt too advanced, also is your DC headers the old type that only reads off one ofthe primary runners? If so you might want to weld bung into the lower collector so it can get a reading from all four since the old DC headers were notorious for bad O2 readings because they only read off one cylinder

 

post all the Co, HC, Co2, O2, and NOx numbers...