The Old max didn't pass smog for the first time ever! The car has 96,000 miles on it (1997). My HC was over the limit for Cali reg the MAX amount is 100 PPM mine was 161 PPM. I did a tune not too long ago (75,000miles) new plugs, PCV valve, and Fuel filter. The guy said its either a wornout CAT, advanced timing, or vacum leak. The Car has a CAI intake, Y-pipe, and custom piping w/out resonator. The car has passed smog 3 times before with all these mods. I was thinking about cleaning the air filter and adding blue sky clean air additive for smog tests. What do you guys think is the problem, and any opinions on a solution. One other question what is factory Idle set at? Mine is at like 650-680rpm.

 

I doubt it's advanced timing unless you have piggyback electronics.

First off bang on your cat convertor and check for broken elements rattling around. If you hear noises of small particles there's a good chance it is shot.

Also find a shop with a smoke machine and check for vacuum leaks.

When the above is checked out, drive your car and get the motor temp as hi as possible and go to a smog shop where there is no line and smog it!

 

Find a different shop and tell the mechanic youll give him some extra cash if he passes the car...

 

Not going to happen, but thanks

 

Oh hell yeah.

 

how about no.

high HCs means its running rich. or it could mean bad cat. considering thats whats supposed to break down the HCs. be careful about bangin on it listening for loose pieces. although that is a valid test, cats can fail and not have loose pieces.

edit: im not 100% positive on this...but i think a vacuum leak would cause a lean condition because it is letting false air into the engine. and high HCs out the tail pipe means rich.....see where im going?

 

The best way to test is to check inlet versus outlet temps. The outlet temp of the cat is supposed to be HIGHER than the INLET temps. So wherever you take it they need to have a pyrometer or something to check.

 

(deleted so theres no confusion)


EDIT: someone me. i stand corrected. outlet should be a little higher