Didnt Pass Emissions
Thread Starter
Intermediate
Joined: Aug 2004
Posts: 49
Likes: 1
From: Crown Point IN
Well they gave me the basics to try which I need to get started on but I was just seeing if anyone has had problems before and what they did to fix them. It is the LT1 92 by the way with 84,000. I am just thinking of changing the plugs and wires and air filter and throw some fuel additive stuff in there and give it another go.
Race Director
Joined: Aug 2002
Posts: 16,024
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From: Stratford Ontario
Originally Posted by jdawgC4
Has anyone had troubles passing emisison tests? My hyrdocarbons were to high. Any suggestions or comments would be appreciated.
Thanks
Thanks
Pro
Joined: Sep 2003
Posts: 670
Likes: 1
From: charlotte nc
Originally Posted by jdawgC4
Has anyone had troubles passing emisison tests? My hyrdocarbons were to high. Any suggestions or comments would be appreciated.
Thanks
Thanks
Thread Starter
Intermediate
Joined: Aug 2004
Posts: 49
Likes: 1
From: Crown Point IN
The wires, cap and plugs have not been changed. I am not sure about the O2 sensor either, I am guessing it has not been replaced before. It is easy to start and I dont believe it has rich smelling exhaust. I did notice on a cool night a good amount of vapor showing in the exhaust, but Im not sure what that means, a lot of cars do that. So basically I should just replace plugs wires and cap and 02 sensor and try it after checking the plugs? Then if that doesnt work move on to the cat converters? It is hard to believe that a piston is misfiring as it runs really well and is very responsive. I am guessing a leaking injector would cause a performance decrease also. DAMN EMISSIONS!
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Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Frankly, I'd get it scanned and verify closed loop status - then look at the block learn to see how close it is to 128. Generally, anything that will go closed loop and has a decent block learn, is going to pass HC's. Those that don't, yet run ok, probably have O2 sensors that are on the fritz.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by ZylaRace
HC is unburned fuel. Start by looking for a bad/weak cylinder. i.e. Cyl not firing. ..... pull the plugs and see if they tell you anything.
Leaking inj can do the same to the HC #'s.
Leaking inj can do the same to the HC #'s.
CO (carbon monoxide) indicates a rich mixture. HC (hydro carbons) is unburned fuel. Plugs, plug wires, and dirty oil (contaminated with blowby gasoline) are good possibilities. The air cleaner would affect the CO more than the HC. I once had a lean misfire (high HC) caused by an over active EGR valve. How close was it to passing?RACE ON!!!
Last edited by CFI-EFI; Aug 11, 2004 at 10:56 AM.
Thread Starter
Intermediate
Joined: Aug 2004
Posts: 49
Likes: 1
From: Crown Point IN
Originally Posted by CFI-EFI
CO (carbon monoxide) indicates a rich mixture. HC (hydro carbons) is unburned fuel. Plugs, plug wires, and dirty oil (contaminated with blowby gasoline) are good possibilities. The air cleaner would affect the CO more than the HC. I once had a lean misfire (high CO) caused by an over active EGR valve. How close was it to passing?RACE ON!!!
I believe my reading was a 1.36 and i need a .80 to pass but I dont know what units they are using so I dont know if that is much help to you. Thank you for everyones suggestions!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It sounds like you have yor gasses mixed up. HCs are measured in parts per million (ppm). They are whole numbers. 220 ppm is the standard for my car, here. CO is measired in percentages, like you are reporting. Is it HCs or CO that is too high. MY answer was based on the question, concerning HCs.
RACE ON!!!
RACE ON!!!
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
It would help to see ALL the #'s,.... NOX, HC, CO
Responsive or not,... it is hard to "feel" an intermittant miss @ RPM. The test is done @ speed. (I forget that actual tire speed.) A dead cyl,... yeah you'd feel that. (Your suggesting you don't have that.)
Responsive or not,... it is hard to "feel" an intermittant miss @ RPM. The test is done @ speed. (I forget that actual tire speed.) A dead cyl,... yeah you'd feel that. (Your suggesting you don't have that.)
Le Mans Master
Joined: Nov 2002
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From: Corvette valley Georgia
St. Jude Donor '06
Originally Posted by ZylaRace
HC is unburned fuel. Start by looking for a bad/weak cylinder. i.e. Cyl not firing. ..... pull the plugs and see if they tell you anything.
Leaking inj can do the same to the HC #'s.
Leaking inj can do the same to the HC #'s.
more than likely the injectors are bad.
Race Director
Joined: Aug 2002
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From: Stratford Ontario
Originally Posted by CFI-EFI
No EGR would cause high NOX (nitrides of oxygen) and not hurt the CO or the HC.
RACE ON!!!
RACE ON!!!
EGR definitely did affect the NO ppm in my case. I tested at 926 ppm (ppm limit is 484) After changing the EGR for the retest the reading dropped to 802 ppm. I still failed mind you; but I know my passenger cat is shot. With both of those problems my HC and CO% was well below the limit both under load (40 km/h@ 2154 rpm) and at idle (1083 rpm).
I hope all this stuff helps your diagnosis.
