masblue

sup miata people,

my miata is having a hard time passing smog here in CA. i did a minor tune up. i already change spark plug, spark plug wires, oil, fuel filter, air filter, PCV valve. on the test result its says NO (PPM) (15MPH) MAX 847 and mine came to 1264 and (25 MPH) MAX 786 and i got 1046. this is what im failing. here's the copy of my test result. 1st test no tune up did better.2nd test did a tune up and failed a lot worse than the first. What could it be the problem? timing? catalytic converter?

Document.pdf

BenR

iTrader: (2)

What is your timing set at? Does your cat rattle? What does your compression look like?

Braineack

iTrader: (62)

high NO is high temps typically lean....

Toddcod

iTrader: (8)

Make a friend with a tow truck driver. They always know someone that can pass you. It usually cost twice what regular inspection is.

masblue

Stock timing and yes i hear a rattle when i drive the car. what should my timing be?

high NO is high temps typically lean....what do you mean??

sorry i'm no professional mechanic.

miataz

iTrader: (1)

rattle is your cat going, or is shot already, and your O2 sensor is probably shot. Happened to me

masblue

Great!! i guess is my cat then thanks for your help people!! i'll let you guys know what happen.

masblue

can the O2 sensor go bad if your catalytic goes bad??

Braineack

iTrader: (62)

if the o2 sensro was bad, he wouldn't have high NO and pass the rest. high NO means a lean fuel condition. so yeah the cat could be gone. but the o2 sensor is working. when the 02 sensor fails, you'll go **** rich in fuel and fail CO and HC.

or the ignition timing is off.


but i'd pull the cat and check it i guess.

leshok

iTrader: (4)

I'd guess cat if rattle is heard.

Why not try. 30% methonal and 65% regular unleaded and 5% water

works for luke.

masblue

good info guys help me a lot and save me money also..Thanks a lot people!!

TonyC

after you get a new cat, be SURE you make sure your car has been run long and hard (and hence the cat's hot as well) before you hit the smog's dyno.

it makes a huge difference. miatas run clean (will pass even w/ headers, etc.). your car has to be pretty effed up to fail smog.

masblue

yeah i will..my miata runs smooth after i got a minor tune up. i was suprised when it failed.