Could really use some help from my CF brethren. Yes, CA smog laws SUCK but let's skip the "just move out of CA dude" responses, thank you.

I bought a 03 Z06 from a forum member, who had it smogged two years ago.

Mods are:
LT's with unknown high flow cats, Comp cam 236/242 114 lsa .601/.610, polished TB, Calloway honker, tuned.
Dyno Sheet

Smog shop I went to tried to run it (yes, I had driven it a lot...then the car was off only for about 5-10 minutes than was idled for about 10 minutes before being run on the smog machine, so I'm assuming the cats were hot). The tech said it would have failed, ONLY due to high HC's.

I then threw a gallon of denatured alcohol into it (into a tank that had about 8 gallons of 91 in it)...we let it run for a bit more (holding rev's), got the cats quite hot and they gave it a couple more tries over about 20 minutes to run smog.

In the end, the car/cats were very hot...at idle it was still blowing way high HC's...while under load at 15mph my HC's were high at around 66. FAIL. At 25mph however, I'm good to go, as the HC's were as low as 31. Passes smog at 25mph!

Don't know what to think. I found a thread here where Z06supercharged posted a list of all the reason's for high HC's.
CF Thread on SMOG

O2 SENSOR:
I had an front heated O2 sensor code a couple of months ago - I had the occasional sulfur/rotten egg smell while at stop lights/driving too. I cleared the code and the code never came back. Took the car to TPS for a bunch of work - they checked it and said the 02 sensor is still working. I'm still smelling sulfur/rotten egg smell from time to time so it makes me wonder what is going on and if this is related. Hope I am not burning up my cats. No other codes to date though. Perhaps I still should of had them change the sensor regardless...

CATS:
My after market high flow cats can't have that many miles on them - likely no more than 8k or so miles. Again, I'm not sure if I have any issues there.

OIL:
I had the oil changed about 1000 miles ago, but the car is obviously running rich at idle (I can smell it!) so perhaps I should have changed the oil again before running SMOG?

AIR FILTER:
My bad, I didn't check/clean the air filter. I still don't know if it's dirty.

PLUGS:
I didn't check my plugs.

As you can tell, I'm no expert here; please, I could use some help. Based upon all of the above, any thoughts on what I should try? What order to proceed?

Will I likely need a new tune in order to pass?


THANK YOU for any help you can lend.

Here is one shot of the SMOG screen at idle:

 

I'm amazed you didn't get dinged for the long tubes and high flow cats. You are fortunate there! Last time I went through smog I tested a bit high in the HC's. The tech told me it was a result of being lean in the fuel trim.Don't know if this helps. I wish you well on getting the HC's in line.

 

My thoughts are that he paid someone off to pass emissions. That cam is way out of spec to be California compliant. In all my research and discussion with tuners, a 224/228 duration, less than .600" lift, and 114lsa or higher lsa cam is about as much as people go when needing to pass the sniffer.
Im pretty sure that no matter how good the tune, that cam will cause emissions to be high.
Cars do get more efficient at higher rpm, so I think that would be normal to pass at the higher rpm. But that cam is just to aggressive to be friendly around idle.

 

To bad you are doing it now.

As of 2013, Calif changed the smog test on OBD equipped cars to just a plug in and pass (or fail).

http://www.smogtips.com/new-smog-law-AB-2289.cfm

 

Unfortunately - I don't think that cam will ever pass - too much overlap

 

Yes, but we don't know yet exactly what this implies. Allot of people are looking forward to this, but I am skeptical still.

Perhaps if they hook into the OBDII and see that O2 sensors are either absent, or tampered with, likewise for the MAF and other sensors, the car my be failed. It may be even harder to pass now that you don't simply need to have no engine codes and pass the sniffer.

I fear that now cars will have to be within factory parameters of all emissions related equipment. This is a possibility and would make many modifications grounds for failure.

Lets hope its nothing this serious. But they will find a way to get people to spend money with this new setup.

 

agreed

 

The root of all evil is lack of education. Read

 

If you have any means to SCAN/DATALOG, do so and see if your O2 sensors are cycling properly and providing the correct output at idle.

You can also make sure that you dont have a lot of PVC system blow by oil in the intake manifold. Before I installed my CATCH CAN, the floor of my intake manifold was saturated with oil.

What are your LTFTs reading at idle?

Bill

 

Gee thanks. The most asinine input I've ever received on the CF.

You want to know about setting up and roadracing bikes? Have you covered. Want to know about Cloud services? Have you covered. Corvettes? Still new to me. That's why I come this forum, to get helpful input...and be told where I need to go/study/read.

Your arrogant, condescending attitude/input is not helpful.

 

...willl check all of this. Thank you.

 

Thanks to everyone (else) for the input. Hope this isn't the case with the CAM - we'll see. Have someone working with me to make sure. If not, I do have a backup plan. For a couple years at least.

 

Ya if you have to pay somewhere off, go for it. But that cam will need swapped for something less aggressive to pass for real.

 

Where in Cali are you? (sorry if you said it and I missed that detail)
I'm in Salinas but go up to SF regularly, if you are local and need someone with a scanner that can pull the LTFT numbers let me know, I have a pretty decent OBDII scanner. I might not know what all the info it shows really means but that part can get posted up here for the experts

 

OP.... I'm feeling your pain. My car passed smog the last two times (e.g. twice in 4 years) but this year, my same smog guy who I have gone to for over 10 years wouldn't test me. I'm currently exploring the options.

 

Yea, that cam's too big and we will have a new way of SMOG inspection starting 1/13 which little is known about. If you can find a way to pass SMOG this time around, that will give you time to look at the new system and put a smaller or stock cam as needed. Good luck.

 

I'm in the bay area. THANK YOU Shok, I think I have it covered for now...will ping you if not. Truly appreciate the offer.

 

Ouch. Sorry to hear and good luck Bud.



Noted. Yeah, we'll see soon enough I guess. Thanks.

 

I'd consider taking it to a well known Corvette tuner, and also strongly consider swaping out the catalytic converters, even though you think they're not bad.

 

This advice is so simple I hesitate to mention it, but just in case, here goes.

I have had some marginal , from a smog license point of view, cars. I always try to take all my cars out for a long , fast drive on the freeway to blow it out, than take it straight to be smogged.

Some cars it doesn't matter. One car I took over cold and it failed smog, so I waited a week, went for a drive before the retest and passed.

As an aside, I used to have a rotary engined RX7. The dealer tech was telling me how people would bring in their new cars, saying it was running like crap. They were told to leave the car, and the next day the tech would run the car up and down the freeway out in front in third gear at the red line, until the thing started firing correctly. I was too polite to ask about the fee, but I was never bashful about winding that car out after that little talk.

Maybe your car is a little high strung for slow driving, perhaps a hot run will clean out the pipes and it will pass. It would seem easy to contact the old owner for advice, if you still have a relationship.

Or you could ask around when you see a gardener. Some can't afford good cars, so they have to resort to bribes to pass smog, from what I hear. Not that I suggest this as an answer to the poster. Just sayin' to run my mouth.