Just failed Smog Test
Thread Starter
Race Director
Joined: Jun 2000
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From: Oakland CA
St. Jude Donor '03
Just failed Smog Test
:mad This sucks. Here are the numbers:
Idle: 630rpm %CO2: 13.9 %O2: 0.9 HC (ppm): 108* CO(%): 0.76 Fail
2500rpm %CO2: 14.4 %O2: 0.4 HC (ppm): 16 CO(%): 0.53 Pass
The 108 ppm HC is the reason I failed. I can't wait to see the look on the face of mechanic at the repair shop that I take the car to for the diagnostic and repairs. I am sure they are going to be licking their chops. Anyone know a reputable enhanced smog test and repair shop in the Fremont area? The shop I took it to only does the tests no diagnosis or repairs.
Idle: 630rpm %CO2: 13.9 %O2: 0.9 HC (ppm): 108* CO(%): 0.76 Fail
2500rpm %CO2: 14.4 %O2: 0.4 HC (ppm): 16 CO(%): 0.53 Pass
The 108 ppm HC is the reason I failed. I can't wait to see the look on the face of mechanic at the repair shop that I take the car to for the diagnostic and repairs. I am sure they are going to be licking their chops. Anyone know a reputable enhanced smog test and repair shop in the Fremont area? The shop I took it to only does the tests no diagnosis or repairs.
Race Director
Joined: Oct 1999
Posts: 13,298
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From: Somers NY
Re: Just failed Smog Test (mash557)
Is your car STOCK... I don't think an oil change will make any difference.. I know of 1 or 2 places here in Ny & some in Ct. that I can get a Nitro burning Coupe to pass... :D
Especially if you have a modified car, you have to plan ahead for smog tests..
In Ca. there are just TOO many TREE HUGGERS... and they made a nice state a real PIA to live in...
my .02
Especially if you have a modified car, you have to plan ahead for smog tests..
In Ca. there are just TOO many TREE HUGGERS... and they made a nice state a real PIA to live in...
my .02
Le Mans Master
Joined: Dec 1999
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From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Just failed Smog Test (94 LT1 Lou)
You sure that's right???? CO2 that high with HC that high? Very strange to me. Do you have the NOx measurements? Quick look says they screwed this test up or their was raw gasoline getting into the exhaust somehow. With HC that high, CO2 should go way low, but it didn't. So I would think that if it DID happen, that there is raw gas getting into the exhaust somehow but don't know how, maybe one dead sparkplug?
Le Mans Master
Joined: Oct 1999
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From: Sachse Texas
Cruise-In I Veteran
Cruise-In II Veteran
Re: Just failed Smog Test (94 LT1 Lou)
Turn the idle up. 630 RPM!? I can't even remember the day mine would idle that low. Modify the set screw in the throttle body to idle the car at 800 since it looks like you passed fine at 2500. If you do this, you may have to set it a couple time to max out the IAC motor so it doesn't adjust it right back down.
That is one option to having to pay someone to look at it.
That is one option to having to pay someone to look at it.
Le Mans Master
Joined: Jan 2000
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From: Thornton CO
Re: Just failed Smog Test (Vette92)
How long had your car been running??? You need to make sure it's been running at least 30 minutes or so to make sure the Cats are up to temperature. Also, you might just replace those O2 sensors - they could be bad!
Burning Brakes
Joined: Feb 1999
Posts: 1,157
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From: Encino CA
Re: Just failed Smog Test (94 LT1 Lou)
Hey Lou--same basic question as others--is the car stock? I have a 95 LT-1 and am in the Los Angeles area and have never even come close to failing the smog test (have always done the test at the Chevy dealer). I have a few minor mods but I set the Hypertech programming back to stock when I take a smog test. Sounds like the smog test shop may have done something wrong.
Racer
Joined: Aug 2000
Posts: 272
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From: Livonia MI
Re: Just failed Smog Test (94 LT1 Lou)
I used to be an expert at getting my old cars to pass the smog tests.
The most important thing to do is make sure the car is good and hot. The best way I found was to take it out on the highway for 15 or 20 minutes. You don't need to hit high speeds, just cruise at a normal highway speed. Head straight into the test station and do not shut off the car. The last time I had a failure, the highway drive dropped the HC levels 30%.
If that fails to drop your levels, you can add a few bottles of fuel injector cleaner to a nearly empty tank.
I hope this helps.
Mike
The most important thing to do is make sure the car is good and hot. The best way I found was to take it out on the highway for 15 or 20 minutes. You don't need to hit high speeds, just cruise at a normal highway speed. Head straight into the test station and do not shut off the car. The last time I had a failure, the highway drive dropped the HC levels 30%.
If that fails to drop your levels, you can add a few bottles of fuel injector cleaner to a nearly empty tank.
I hope this helps.
Mike
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Melting Slicks
Joined: Jan 2000
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From: NW Chicago Suburbs
Re: Just failed Smog Test (PeteL)
....With HC that high, CO2 should go way low, but it didn't. So I would think that if it DID happen, that there is raw gas getting into the exhaust somehow but don't know how, maybe one dead sparkplug?
Eric
Thread Starter
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From: Oakland CA
St. Jude Donor '03
Re: Just failed Smog Test (mash557)
I had changed the oil the day before, mobil 1 tri-synthetic. While I was under the car on the ramps I looked at the O2 sensors and thought about changing them but I didn't think I would have any problem passing so I left them alone. The only changes I have made to the car are NGK plugs, Taylor 8mm wires, K&N filter. I took the car for a drive before the test but the shop was busy and the car sat for about an hour before they did the test. They took the keys so I couldn't let the car run while I was waiting. Another funny thing is every car that was tested before me failed. I have been directed to a shop here in Fremont where they can re-test it and diagnose any problems. I'm taking it in Friday morning. Hopefully I will have better luck.
Drifting
Joined: Mar 2000
Posts: 1,630
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From: Woodstock GA
Re: Just failed Smog Test (94 LT1 Lou)
I would think the O2 sensors are getting slow and are unable to keep it were it needs to be. I am assuming the car seem to run good with no rough idle. The car should be able to pass even with most mods with the exception of adjustable fuel pressure regulator that is set way to high, but with a good O2 sensor and cats there should be no problem. The key to any feed back fuel magment system is the O2 sensor I would also recomend you keep with Delco O2 sensors that's what the car was calibrated for and some aftermarket O2 sensors will work but not be the same calibration and you can fail an emission test.
David Fulcher
David Fulcher
Thread Starter
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From: Oakland CA
St. Jude Donor '03
Re: Just failed Smog Test (David-F)
The car seems fine to me. The rpms are a little low at idle but it's not rough. The O2 sensors are original, about the only thing left on this car that hasn't been replaced, outside of the engine bay. The shop I am going to tomorrow moring is right next to a chevy dealership. I'll stop by and pick them up before I bring the car in. Thanks for all your suggestions.
Le Mans Master
Joined: Dec 1999
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From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Just failed Smog Test (94 LT1 Lou)
If they tested you car cold, that is at least part of the problem. Probably why everybody failed.
Was the engine at least at operating temperature? Did they warm it up before putting it on the dyno or just drive on and test?
If they tested that car cold and you paid money you need a refund, and I would also look for some waste of time and effort money.
How low is idle, does it hunt?
[Modified by PeteL, 7:39 PM 1/24/2002]
Was the engine at least at operating temperature? Did they warm it up before putting it on the dyno or just drive on and test?
If they tested that car cold and you paid money you need a refund, and I would also look for some waste of time and effort money.
How low is idle, does it hunt?
[Modified by PeteL, 7:39 PM 1/24/2002]
Drifting
Joined: Aug 2000
Posts: 1,614
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From: Colleyville Texas
Re: Just failed Smog Test (94 LT1 Lou)
Look for the old run down Sunoco stations from the 50's with alot of old cars and motorcycles sitting out front and guys from the "Deliverance" movie doing the testing. :D
[Modified by Red Rocket, 7:25 PM 1/24/2002]
[Modified by Red Rocket, 7:25 PM 1/24/2002]
Thread Starter
Race Director
Joined: Jun 2000
Posts: 13,128
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From: Oakland CA
St. Jude Donor '03
Re: Just failed Smog Test (Red Rocket)
I passed the smog test this morning with no problems at a different shop. I haven't even changed the O2 sensors yet. I was able to drive the car right in and get the test done with no wait. Thanks for all of your help.
:D
:D
Melting Slicks
Joined: Jan 2000
Posts: 3,418
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From: NW Chicago Suburbs
Re: Just failed Smog Test (94 LT1 Lou)
I'd still purchase some new O2 sensors and install them myself. Cost is ~$60 from an internet parts guys like 18carfan and 8 years is long time for an O2 sensor.
Just my opinion, FWIW,
Eric
Just my opinion, FWIW,
Eric
