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Failed Emissions Please Help

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Old 01-15-2005, 02:20 PM
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Car: 1991 RS Camaro Convertible
Engine: 305
Transmission: 700R4
Failed Emissions Please Help

Hi Everyone,

I took the car in for inspection today and it failed on emissions,one front tire and emergency brake. It failed on the low speed emissions. The car is a 91 RS Convertible 305 TBI.

The emission readings were as follow:-

Standard Current
HC(PPM) 120 196
CO (%) 0.67 0.28
CO2(%) 14.3
O2(%) 0.8
NOx(ppm) 907 1472
DILUTION(%) >6 14.6

What I have noticed is a broken component in the engine bay,I think its the air diverter valve.Could this be the problem?

Have enclosed a picture.

Thanks,

Alex

Last edited by aldixie; 08-13-2006 at 11:05 PM.
Old 01-16-2005, 11:48 PM
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Car: 82 Berlinetta/57 Bel Air
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It could be the reason.

They're available at parts stores. Would be worth it to fix it. And do a tune up while you're at it if you haven't already.
Old 01-17-2005, 07:53 PM
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judging from your nox reading, i would say the diverter valve would definetly be a large part of the problem. it supplies oxygen to the cat to aid in the reduction of nox. hydrocarbons seem high, too. whens the last time you tuned it? oil age can also have an effect on hc readings, as the oil in the pan soaks up fuel that inevitably gets past the rings.

Last edited by raceb8; 01-17-2005 at 07:57 PM.
Old 01-22-2005, 04:50 PM
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Car: 1991 RS Camaro Convertible
Engine: 305
Transmission: 700R4
Originally posted by raceb8
judging from your nox reading, i would say the diverter valve would definetly be a large part of the problem. it supplies oxygen to the cat to aid in the reduction of nox. hydrocarbons seem high, too. whens the last time you tuned it? oil age can also have an effect on hc readings, as the oil in the pan soaks up fuel that inevitably gets past the rings.
Hi All,

Got the car thru the inspection. It was the air diverter valve. Tried my local autozone and it was $208 + Tax. Found someone in the classifieds who had one for $25 including shipping. Thanks Ben.

Getting a real kick out of driving the car especially with the top down.

Old 01-22-2005, 06:17 PM
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Car: 1991 Chevy Camaro
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 3.42
Found someone in the classifieds who had one for $25 including shipping. Thanks Ben.
Your welcome. Glad I could help.
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