Ahhh.  Failed The Room of Doom in California, eh?

Post your numbers and the limits.  HC and CO for what might be wrong, and O2 and CO help determine converter health.  Also your Corvette's year would help.

Slightly elevated HC and CO usually indicate an ineffective catalyst. High HC by itself is a misfire. High CO is running rich, and will also be accompanied by high HC.

Google "5-gas emissions analyzer readings" to furthur your understanding of emissions test results. Here's the one I'll study later to re-fresh. http://www.autoshop101.com/forms/h56.pdf

I am moving from Michigan to California for my retirement and dread the smog test for my 86.

I'll Post the results soon, I retest tomorrow ,I changed the Oil , Knocked the Timing down 2 Deg.  from 6 DEG.  to 4 DEG.  ( Car seems to like 4 DEG. Better ) no more pinging , I'd just realized it had been  1-1/2 years since my last  Oil Change   Shame on me  for not  keeping up with that  ...too many cars & not enough memory on my part . I will get those numbers up soon.  

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My Corvette Pic

Fail twice, and you're a "Gross Polluter".  I'm not sure what it takes to pass after you receive this distinction, as I have never had one of my personal cars fail a smog inspection (seriously) in the 40+ years I've lived in SoCal.  I was a Cali liscensed smog tech for about 10 years, and carried an ASE Master Auto Tech cert for 30 years. I know quite a bit about emissions, testing, and systems interactions.  I was asking for your test numbers to see if I could help you zero-in on the actual problem, and increase your chances of passing the Room of Doom on the next test. Not out of curiosity. Oil changes aren't likely to help much, and the timing should be set to the spec on the under hood sticker, as the technician is supposed to verify the setting.

Good Luck

You may want to consider a pre-inspection in order to avoid the Gross Polluter designation.   If it turns out your car isn't going to pass, the pre-inspection results won't count against you.  Then, you can use the help here on the forum, along with help from your repair shop, to get the car passable.  Take the "real" test when you know you're passable, and you can avoid Gross Polluter status.  

|UPDATED|7/31/2013 8:44:46 AM (AZT)|/UPDATED|


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I had a gross polluter once.  Had to go to a "Gold Shield" certified station to clear the name.  Same price but wondering why it was special.  It only passed after doing a valve job.  One exhaust valve not sealing and burnt.  Good 'ole Ford inline six.

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If it isn't broke, I haven't fixed it yet....

Here are those numbers  @ 15 MPH (CA -Max) is  78 ppm / mine was @ 96 ppm

@ 25 MPH ( Ca-Max ) 86 ppm / Mine was @ 115   these are for  the  Hydrocarbons ( HC )

(CO) are as follows CA-Max is @ 15 MPH  0.51% / Mine was @ 0.36%

@ 25 MPH CA-Max is  0.42% / Mine is @ 0.43%  ( CO)

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My Corvette Pic

Now as far  the  ( HC ) ,  Used motor oil carries a  very high  number of  Hydrocarbons , I've hauled it , cleaned it , & refined it . Too much timing  can also raise HC #'s  , A dirty air filter  can also . And  the list goes  on My  father in law worked for  GM and  has worked on many  C4's . Even though the  factory setting is @ 6 deg.  he said  most C4's  are happy  @ 4 deg. From what the  smog tech told me  it shouldn't take  much because  those are not  high numbers  and should be easy  fixes  .I also checked  the  CA ( State ) web site for more  info , They echoed the  same, dirty oil, air filter & timing being too high could very well be the  case . We shall soon see , I'd  like to thank every last one of you with your  great input & info .....I hope I can return the  favor 1 day 

|UPDATED|7/31/2013 5:11:24 PM (AZT)|/UPDATED|


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My Corvette Pic

I live in east Kern county and we don't have the dyno test.  We just do idle and 2500 rpm check.  My last test revealed HC was 30% of allowed and CO was 40% of allowed.

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If it isn't broke, I haven't fixed it yet....

Well....The results are in, It passed with  flying colors with just a  Oil , Air filter Change & knocking down the  timing  3 degrees. Here are the new  numbers  , @ 15 MPH the ( HC ) was 35 PPM / Max is  78 PPM.  @ 25 MPH  it was @ 39 PPM ( HC ) / Max is  86 PPM .

(CO) @ 15 MPH was @ 0.13% / Max is 0.51% , @ 25 MPH was  @ 0.32%  / Max is 0.42 , I'm very happy these things worked out. Kudos to you all .

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My Corvette Pic

Glad to hear you passed for another 2 years!

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