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Old Sep 4, 2008 | 10:56 PM
  #1  
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Default 993 Failed

Need help understand the numbers from my failed smog test only. Would like to hear from others prior to the Mechaanic going after the prolem.
1995 C2 with 65,000 miles.

15mph@1531 rpm CO2 14.7..HC(PPM) 142..CO(%).07....NO (PPM) 0
25mph@1678 rpm CO2 14.6..HC(PPM) 47...CO(%) .05...NO (PPM) 0

It passed at 25 mph but not at 15mph...HC was the problem where max HC 85 (PPM) and was just barely under the 25mph Max for HC of 50 PPM. Any and all suggestions on the numbers would be appreciated....Roger
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Old Sep 4, 2008 | 11:10 PM
  #2  
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A little info to get you started at this site.
http://www.txdps.state.tx.us/vi/Misc/faq/faq_asm.htm

Dave
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Old Sep 4, 2008 | 11:23 PM
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rampfar: I, too, have wondered where other 993s are in the test. Would be interesting to see how others track with the State's "AVE" measurements. Here's mine from last month:

15mph@1640 rpm CO2 14.6 .. HC(PPM) 23 .. CO(%) 0.03 .. NO(PPM) 30
25mph@1664 rpm CO2 14.6 .. HC(PPM) 3 .. CO(%) 0.00 .. NO(PPM) 13
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Old Sep 5, 2008 | 02:11 AM
  #4  
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My BMW had high HC at low speed, a new catalytic converter solved the problem
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Old Sep 5, 2008 | 02:44 AM
  #5  
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1996, bone stock with 27,000 miles - just smogged at a test only in SF last month. Here are the numbers:

RPM------CO2-----HC max------HC Measured----CO max----CO measured
807-------15.1-----100 ppm--------3 ppm----------1.00%---------0.0%
2382------15.2-----130 ppm--------1 ppm----------1.00%---------0.0%

It appears that I passed by a mile so there must be something wrong if your numbers are really different. FWIW I drove the car hard before I took it in and they ran the test within 5 minutes from when I arrived.
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Old Sep 5, 2008 | 06:02 AM
  #6  
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The hot ticket is to drive the car hard and take in hot. It will make the difference in passing or not. It is all in the cat. GOOD LUCK....
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Old Sep 5, 2008 | 06:32 PM
  #7  
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Originally Posted by rampfar
Need help understand the numbers from my failed smog test only. Would like to hear from others prior to the Mechaanic going after the prolem.
1995 C2 with 65,000 miles.

15mph@1531 rpm CO2 14.7..HC(PPM) 142..CO(%).07....NO (PPM) 0
25mph@1678 rpm CO2 14.6..HC(PPM) 47...CO(%) .05...NO (PPM) 0

It passed at 25 mph but not at 15mph...HC was the problem where max HC 85 (PPM) and was just barely under the 25mph Max for HC of 50 PPM. Any and all suggestions on the numbers would be appreciated....Roger
Roger,

Call me,...
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Old Sep 5, 2008 | 07:18 PM
  #8  
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15 MPH is too slow for these cars... that's the problem right there!

Seriously, I'm glad we don't have to smog here.... yet.
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Old Sep 5, 2008 | 10:56 PM
  #9  
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Steve....Thanks for the adise....and confirmed with Don it would be worth a try.....I will give you an update next week..Roger
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Old Sep 5, 2008 | 11:44 PM
  #10  
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My 77 Bronco runs rich so I turn down the carb until it barely idles---passes with flying colors then. Im taking it tomorrow for safety for the yearly safety and emissions.

However, never had an issue with my 95 C4 for emissions.

Wish the answer was easy as a screw driver.
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Old Sep 6, 2008 | 01:00 AM
  #11  
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Just a couple months ago I had to throw a new cat on my old BMW to pass smog. I was warned by my indy that the 993 can be difficult to pass as well. (I bought my 993 in Dec and haven't attempted a smog yet.) Seems the conensus is get the car REALLY warmed up. Warm it up and then run it kinda hard for awhile,....get the cats hot and working their best. If you can, go to a smog place that can take you right away. Good luck with it.
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Old Sep 28, 2008 | 12:52 PM
  #12  
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In the spirit of this thread, my beloved 95 c4 failed CA smog this week. The killer was CO at 1.28% with
a max allowed of 1.0 and this used to be down at 0.1. This is at 2500 rpm. My indy sez that it is not
the O2 sensor since they swapped it with a good one. He recommended a new cat. So.. does anybody
have a source for a used Bischof cat, or can anybody rebuild these? The OEMs look like they are $2k.
Or is a sport cat the way to go?
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Old Sep 28, 2008 | 05:13 PM
  #13  
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From: Solana Beach, CA
Smile Re-register your car in San Miguel, CA

Cars from rural areas only need a sniffer test, no dyno! I just passed last week, smog, not gas, nor did I die ...to the best of my knowledge...
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Old Sep 29, 2008 | 01:21 AM
  #14  
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Has the car been "chipped?" I've heard this may cause problems like yours.

Phil
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Old Sep 29, 2008 | 03:05 AM
  #15  
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Originally Posted by fullbooker
Has the car been "chipped?" I've heard this may cause problems like yours.

Phil
Nossir,...not really, Phil.

Performance chips can have side effects depending on whose they are, but those are not the symptoms of poor programming,...
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