failed NOx in emissions test
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Melting Slicks
Joined: Aug 2004
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failed NOx in emissions test
Failed the NOx part of my emissions test with '90 L98. I replaced the EGR valve which was clogged and had it tested again and it still failed but only by a few points, actually it passed the 25 mph part with 1045, 1047 allowed, but the 15mph part was 1197 with 1146 allowed. I have also just installed new y-pipes front and back with one freeflow cat and no precats. After installing the new EGR valve the idle was up a bit which I adjusted back down with the stop screw on the throttle body.
What can it be?? Everything else on the test was real good, just the NOx part. One friend of mine said to take it out on a back road and really blow it out, because excess carbon deposites can have an effect on that reading. This is an A4 trans car that belonged to an older gentleman who never blew it out. Any suggestions , other than take it to a repair shop??
Thanks in advance
What can it be?? Everything else on the test was real good, just the NOx part. One friend of mine said to take it out on a back road and really blow it out, because excess carbon deposites can have an effect on that reading. This is an A4 trans car that belonged to an older gentleman who never blew it out. Any suggestions , other than take it to a repair shop??
Thanks in advance
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Originally Posted by lt4dogman
the idle was up a bit which I adjusted back down with the stop screw on the throttle body.
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,042
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Well today I took it to another inspection station (one that only inspects and does NOT make repairs) and the only difference was I really hammered it a few times on the way over there. It passed with flying colors 
, in fact 400 points better than at the other inspection station 
.
I will report this to the Georgia Clean Air Commision and see if they will go by and do spot check on the station that inspected it the first time. I ask the guy who ran the inspection (the first time) what it could be and he said there were "100 things it could be and you can't do any of them in your driveway!" My impression was it is normally the EGR valve or the catalytic converter. This guy also makes emission repairs..... maybe a little "racket" going on here??!! Also at the second inspection station I ask the mechanic why they didn't have a camera behind the car mounted on the ceiling like the first inspection station and he said because they haven't been in any trouble, the state only puts the camera up when the inspection station has not been on the up and up.
, in fact 400 points better than at the other inspection station .I will report this to the Georgia Clean Air Commision and see if they will go by and do spot check on the station that inspected it the first time. I ask the guy who ran the inspection (the first time) what it could be and he said there were "100 things it could be and you can't do any of them in your driveway!" My impression was it is normally the EGR valve or the catalytic converter. This guy also makes emission repairs..... maybe a little "racket" going on here??!! Also at the second inspection station I ask the mechanic why they didn't have a camera behind the car mounted on the ceiling like the first inspection station and he said because they haven't been in any trouble, the state only puts the camera up when the inspection station has not been on the up and up.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by lt4dogman
the state only puts the camera up when the inspection station has not been on the up and up.
RACE ON!!!
