RCF925

Sounds like the Cat to me. I had trouble getting past smog on my last Blown 355 with a pretty big cam. I put on a new CAT and passed easily. As you can see I'm also in Ca.

dnz28

Here this is how I passed go to walmart get a air tank fill it up, drill a hole in you muffler weld a air fitting in there then right before the test say I need to get something out my trunk turn turn on the air tank and bam you will have the hp of a camaro and the emissions of a honda!!!!

KeVMaN

yea that would almost work...

Z95m6

have you replaced the O2's yet?

DrewHMS97SS

is your check engine light on? does it flash?

The engine light is pretty much anything emissions related. It will also come on if the car miss fires. it will flash in this case the number of the cylinder. IE 3 flashes is cyclinder 3. if it keeps flashing there are a lot of missfires. take it somewhere with a snapon scanner. they can tell you the codes in the pcm and for instance how many misfires have occured.

Nuke

Are you absolutely sure that your spark plug wires are routed correctly? This is what jumped out at me from your posts. Looked like you "fixed" a problem with your plug wires and everything went downhill after that.

dnz28

What you mean that would almost work it worked fine for me and look at my mods.

DrewHMS97SS

its a shame, all that work and its not a stick

Fatdog

I've heard that you must change the oil right before the test.Then,the car must be totally warmed up(don't just leave home and drive down the street to the smog place)take the car out and let it rip.Then,when you arrive at the testing center,go in and make the arrangements for the smog test.When they are ready for you,sit out in the parking lot and let the car sit there and get real hot(till the fans come on),then drive in for the test.Seems the sniffer likes a real hot engine to test.(use the 180 stat).Hope this helps.

AndyB

Whats even better is to take the test fresh off the freeway or whever you flogged the car and smog it. The less the car sits and idles the less the cats have a chance to load up.

djs_ta

I used to have an 87 blazer with a 350, about 20,000 miles on the motor, but I had a cracked manifold and a completely hollowed out cat but the truck still passed in Cali. I assume it must have been because of the new cat.

Hmmm. I just read that you placed a new manifold. Well I have a funny story. I just got my car smogged and I have a Borla so I had the closed plate in. I think the smog tech put the sniffer on the end of the borla which no exhaust comes out. If that is so my car must of ran real clean. I doubt it happened, but it looked like that was the side he placed the sniffer on.

Blue_Chameleon

Plugs are good, wires were checked and rechecked. The cat has been replaced and everything seems to be good. O2s are good.

The ONLY thing I can think of is the canister cat. My Z28 has two cats...the regular cat underneath the car and the canister shaped cat. I haven't heard it rattle, or make anything wierd if I bump it with my hand. The cat that I had replaced was the one beneath the passenger seat....that thing rattled like penny in a tin can.

Fatdog

To djsta.I really like your last post.(Story)Thanks.

My94RedZ28A4

Post what your CO, HC and NOx look like. They tell a far greater story then just "Failed"

General rule of the thumb:
+ You want the car HOT
+ Change your oil before you test it
+ you can try a quart of that "guaranteed to pass" crap they sell at wal-mart.
+ you want a clean air filter
+ inflate your tires to max allowable pressure (For the rollers)
+ Make sure the EGR works
- no exhaust leaks
- no vacuum leaks
- if the cat is bad, it will not pass

Blue_Chameleon

Here are my smog results...

http://www.geocities.com/stan350lt1/smog.htm

I don't know why in some aspects, the numbers are getting worse?!