Failed Emissions
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
I may be full of it, but the guy at the test station asked if my 91 was a single or dual exhaust. I said the exhaust runs through a single catalytic converter so it's a single exhaust. Why. He said the readings are doubled in a dual exhaust readout. No matter, I passed the test.
think about it. why would they double the readings for duals? unless they falsely presume whichever side they dont test is automatically producing four times the ammount of pollutants as the one they did??
if they are concerned that a true dual system with separate cats having different readings, then they should test both sides, and require that both pass the established limits...
or they could add each sides figures together, then divide them to get an average for the car...
Racer
Joined: Dec 2006
Posts: 325
Likes: 2
From: Chattanooga TN
i havent seen a fuel injected GM engine in good operating condition, that couldnt maintain closed loop operation at 160 deg.
most are able to attain closed loop by at least 140 deg., some as low as 130...
Drifting
Joined: Jun 2002
Posts: 1,945
Likes: 41
From: Corinth TX
I was having problems with mine passing emissions as well. It was running rich as well so I replaced the O2 sensors. When I pulled them out they were covered in soot. I also ran the car for about 20 mins on the highway to get everything nice and hot. The end result was that the car passed with flying colors.
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
If the emissions are read in PPM and % then the readings would be the same if you were testing one side or both. That is, if both banks are running the same. If you double the volume (sample), a percentage is still a percentage.
The only time the reading would be doubled is if they are measuring in grams. The old IM240 inspections measured in grams. If I remember correctly it was grams per mile. Its been awhile. Dont know if those methods are still being used anywhere. Maybe someone else will chime that knows.
The only time the reading would be doubled is if they are measuring in grams. The old IM240 inspections measured in grams. If I remember correctly it was grams per mile. Its been awhile. Dont know if those methods are still being used anywhere. Maybe someone else will chime that knows.
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
Thread Starter
Instructor
Joined: Nov 2006
Posts: 207
Likes: 0
From: Duluth Georgia
Yay, I just passed the emissions test yesterday. Thanks everyone for the help.
Turns out that I was running a bit rich so I did a basic tuneup, replaced the fuel injectors, replaced the thermostat, and even replaced the valvecover gaskets while I was in there because they were leaking. I have to say that changing the injectors on a L98 is a big P.I.T.A! Anyway, after work I drove over to the emisions place and passed with flying colors.
Turns out that I was running a bit rich so I did a basic tuneup, replaced the fuel injectors, replaced the thermostat, and even replaced the valvecover gaskets while I was in there because they were leaking. I have to say that changing the injectors on a L98 is a big P.I.T.A! Anyway, after work I drove over to the emisions place and passed with flying colors.
Last edited by Cadder; Feb 20, 2007 at 02:35 PM.
