Emissions Test Question-Failed!!
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
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From: Tinley Park, IL.
Emissions Test Question-Failed!!
Hey guys, took my '92 LT1 for the smog test and it failed. Here's the info on the car and the test results, tell me what you think. '92 LT1, new Bosch platinum plugs ( gaped @ factory .45 ), new wires, new MSD coil, new Bosch O2's, new high flow cats, shorty headers, Borla cat back. The rest of the car is stock, heads , cam, computer chip, etc. The car has been sitting in storage for about 5 months with about 20 miles of use over that period. I ran what gas was left in the tank out & refilled it with 93 premium, ran the car for about an hour or so, intown and @ highway speeds ( if just touching 100 mph counts ) and then went and took the test. Here was my readings.---> HC (gpm) 1.60, had to be less then .80 ( failed )--CO (gpm) 25.8, had to be less then 15.0 ( failed ), and a CO2 (gpm) 474.5-not used for test purposes. So, what do you think? Oh, the car has 63000 miles on it . Any ideas on why it failed would be greatly appreciated!! :cheers:
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
Likes: 0
From: Tinley Park, IL.
Re: Emissions Test Question-Failed!! (ezmoney92)
Oh and I forgot to mention, the car ran as good as it ever has if not better. No codes, no hesitations, great throtle responce, etc. Thanks! :)
Race Director
Joined: Aug 2002
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From: tucson AZ
St. Jude Donor '04 & '05
Re: Emissions Test Question-Failed!! (ezmoney92)
If you were in Calif...would be even worse.....
Are you checking what the problems there might be.....did the smog station give you any idea's....
tony
Are you checking what the problems there might be.....did the smog station give you any idea's....
tony
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
Likes: 0
From: Tinley Park, IL.
Re: Emissions Test Question-Failed!! (oldace84)
If you saw the people who work at the smog stations out here you wouldn't even think about bothering with their ideas!! Most of 'em get confused reading your plates! :lol: :rolleyes:
[Modified by ezmoney92, 11:43 PM 11/8/2002]
[Modified by ezmoney92, 11:43 PM 11/8/2002]
Melting Slicks
Joined: Sep 2000
Posts: 3,150
Likes: 1
From: Carlsbad, CA CA
Re: Emissions Test Question-Failed!! (Light84vette)
The spark plugs could be the problem. They are gapped at .45 which is Hot, and probably too hot for emission standards. I would start trouble shooting that first.
Also, when you smog your car you want the cats to get as hot as it can so they can work properly.
Also, when you smog your car you want the cats to get as hot as it can so they can work properly.
Drifting
Joined: Dec 2000
Posts: 1,733
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From: Sarasota FL
Re: Emissions Test Question-Failed!! (ezmoney92)
The O2 sensor is a consumable part and that would be my guess due to the high HC which indicates a rich condition. Since you have new sensors you need to look further.
You probably need heated O2 sensors on your car since you have high flow cats.
Pull the codes, if you are that far off it should give you a hint.
[Modified by DON M, 8:16 AM 11/9/2002]
You probably need heated O2 sensors on your car since you have high flow cats.
Pull the codes, if you are that far off it should give you a hint.
[Modified by DON M, 8:16 AM 11/9/2002]
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
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From: Tinley Park, IL.
Re: Emissions Test Question-Failed!! (DON M)
Hey guys, thanks for the ideas! :yesnod: I did forget a couple of things though, 1. I've got old oil in the car still, not alot of miles ( about year and a half ) but I do run 100 octane race gas. I've heard that a high octane gas can effect your oil, but could it be enough to cause such a seamingly rich condition? 2. I also have an open element breather in place of my oil fill cap, could this throw off the EGR system bad enough to cause these readings? Well, thanks again. :seeya
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Le Mans Master
Joined: Jun 2001
Posts: 6,694
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From: Less Talk, More WOT | Houston TX
Re: Emissions Test Question-Failed!! (ezmoney92)
another thing you can do to help your car pass would be to let it sit outside the inspection place for a while and get hot. The hotter it runs the better the cats will work. I used this technique, let my car sit until coolant was at 230 and oil temp around 225 and I passed with flying colors, and I have no precats and no smog pump.
Pro
Joined: Sep 2001
Posts: 743
Likes: 4
From: Guyton GA
Re: Emissions Test Question-Failed!! (ezmoney92)
Hey guys, thanks for the ideas! :yesnod: I did forget a couple of things though, 1. I've got old oil in the car still, not alot of miles ( about year and a half ) but I do run 100 octane race gas. I've heard that a high octane gas can effect your oil, but could it be enough to cause such a seamingly rich condition? 2. I also have an open element breather in place of my oil fill cap, could this throw off the EGR system bad enough to cause these readings? Well, thanks again. :seeya
2)The race gas is a portion of the problem. It may not be burned efficently and completely on a stock compression engine. If you recently changed gas octane or the O2 sensor(as mentioned earlier), the computer needs to relearn these changes.
3)Yes, put your oil cap back on!
4) A hotter spark plug range may help too.
Le Mans Master
Joined: Oct 1999
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From: Sachse Texas
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Re: Emissions Test Question-Failed!! (merrick)
but I do run 100 octane race gas.
Put some regular 93 octane in there, run it for 20 miles or so getting on the throttle some and then retest it. Like mentioned, the race gas is probably not burning efficiently causing the results to be worse than they should. I would also change the oil before the retest.
Race gas helps run the combustion cooler, not what you want to pass emissions. Hot passes. I would suspect you are simply wasting your money running race gas on a stock engine unless you are throwing a lot of nitrous into the mix or running a blower.
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
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From: Tinley Park, IL.
Re: Emissions Test Question-Failed!! (Vette92)
Well guys, drained the tank and refilled with 92 octane gas, removed valve cover breather and replaced oil fill cap, let computer relearn the new sensors, changed the oil, and added 3 cans of Heat to the tank and my HC stayed at 1.6 ( .8 limit ) and my CO went up from 25 to 33 ( 15 limit ). And now the car is running even better then before. Hmm, I'm getting stumped on this one. Any other ideas? :seeya
Le Mans Master
Joined: Dec 1999
Posts: 8,540
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From: And on the fifth day, subpoenas were served to Obama senior staff
Re: Emissions Test Question-Failed!! (ezmoney92)
You need to get a scanner on the car to determine what is messing up. You are running rich. Is the car going into closed loop? Guess a bad sensor or leak somewhere.
Pete
Pete
Instructor
Joined: Aug 2000
Posts: 118
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From: Union Ky
Re: Emissions Test Question-Failed!! (ezmoney92)
Sounds like your problem is real close to mine. See links:
http://forums.corvetteforum.com/zero...584590#4584590
http://forums.corvetteforum.com/zero...606267#4606267
I have not figured it out yet, but will post the solution when its fixed.
Good luck...Jack
http://forums.corvetteforum.com/zero...584590#4584590
http://forums.corvetteforum.com/zero...606267#4606267
I have not figured it out yet, but will post the solution when its fixed.
Good luck...Jack
Le Mans Master
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From: Sachse Texas
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Re: Emissions Test Question-Failed!! (jmh63)
You might also want to check the condition of the EGR valve. Perhaps it is not functioning properly or possibly hanging open. To easily check it, disconnect the vacuum line form it, press in the diaphram and put your finger over the vacuum. Release the diaphram and see if it holds. If it does, the valve is good and probably not the problem. The other component is the actuator relay next to the EGR. May be holding it open as well.
I do not know a lot about emissions, but I do know if one little thing is malfunctioning, it could through the rest of the system out of whack. I doubt it is something big that is causing the trouble.
I do not know a lot about emissions, but I do know if one little thing is malfunctioning, it could through the rest of the system out of whack. I doubt it is something big that is causing the trouble.
Thread Starter
Racer
Joined: Apr 2001
Posts: 318
Likes: 0
From: Tinley Park, IL.
Re: Emissions Test Question-Failed!! (Vette92)
Well, put the scanner to the car and the only codes I'm getting are for a faulty airbag ground ( ?? ) :rolleyes: and a bad knock sensor. So guess which one I'm goin' to replace. :crazy: Anyways, could the knock sensor be throwing off my timing and fuel curves causing me to run rich? Thanks again!! :seeya
Instructor
Joined: Apr 2002
Posts: 249
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From: Broken Arrow Oklahoma
Re: Emissions Test Question-Failed!! (ezmoney92)
What were your BLM's and Integrator numbers when you scanned?
Also, if you can turn down the fuel pressure this will sometimes help you pass especially if you have aftermarket injectors.
Also, if you can turn down the fuel pressure this will sometimes help you pass especially if you have aftermarket injectors.
