Emission woes
Thread Starter
Pro
Joined: May 2012
Posts: 610
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From: La Plata Maryland
MD Events Coordinator
Emission woes
Recently I took my 02 coupe in for its bi annaual emission test. The tech plugged in the "reader" and almost immidiately said that I did not pass, didn't fail, but didn't pass. Said that the emission computer could not read my computer. Told me to drive it around for a week and let it reboot.
A couple of notes that are important...this spring I installed a set of catted headers, took about 3 weeks. There is a K&N twin cone air filter installed, has been on car since before my last emission test. The car is not a daily driver but I have put a couple of hundred miles since the header install.
Any thoughts or help would be greatly appreciated.
A couple of notes that are important...this spring I installed a set of catted headers, took about 3 weeks. There is a K&N twin cone air filter installed, has been on car since before my last emission test. The car is not a daily driver but I have put a couple of hundred miles since the header install.
Any thoughts or help would be greatly appreciated.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
You need to clarify what could not read means. If his system could not connect to the PCM then the problem won't be fixed by driving it. You may have a blown fuse for the OBDII port power causing a no connect problem. I believe it's a fuse marked as a ALDL in the footwell fuse box.
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
Sounds like your readiness monitors are not set. When I did ET in GA. 2000 up cars could have 1 not ready monitor but not two or more. Luckily GM's are easy to get ready. Just google GM drive cycle and it can be done in about 15-20 minutes.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Let me guess. I bet you no longer have the AIR system and/or the rear O2 sensors and/or the catalytic converters? You probably left off at least one of those systems. If you don't still have all of those in place then you will never pass an OBDII emissions test.
You can consider the emission monitors as self tests for the various emission related systems on the car. You can't pass an emissions test unless all the self tests pass and the self tests won't pass with the systems not in place.
It's really not difficult to make a car pass an OBDII emissions test with the catalytic converters, rear O2 sensors and AIR system all removed but it requires tuning to turn all of the codes off for those systems.
You can consider the emission monitors as self tests for the various emission related systems on the car. You can't pass an emissions test unless all the self tests pass and the self tests won't pass with the systems not in place.
It's really not difficult to make a car pass an OBDII emissions test with the catalytic converters, rear O2 sensors and AIR system all removed but it requires tuning to turn all of the codes off for those systems.
Last edited by lionelhutz; Oct 27, 2014 at 12:58 AM.
Racer
Joined: Oct 2011
Posts: 372
Likes: 2
From: Richmond BC
When you clear codes that also clears the readiness indicators. You need to drive it for a bit and then perhaps stop at a local parts place and have them read the emissions codes. The Readiness indicators do not get reported in the codes pulled through the DIC. Reader that the parts stores have DO read the standardized emissions codes including Readiness indicators but cannot read Corvette specific codes.
I had the same issue with my Caddy. Once I drove it through a drive cycle it passed. Emissions testing in Vancouver ends in December. Thank goodness!
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Race Director
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From: Reno is so close to Hell you can see Sparks , State Of Confusion
St. Jude Donor '12-'13-'14
I am thinking seeing you cleared the codes the same day was your issue, Drive it for a few days and try again. Never clear any codes and then take your car for a test, It will never pass.
Race Director
Joined: Apr 2007
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From: South Western Ontario
It won't pass with codes or with the check engine light on either. You obviously have some issue if you had to clear the codes before the test (which will also never work). So, what were the codes?
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
The good news is in most states you can still pass with one monitor not ready. The good news about that is that the EVAP system and converters take the longest to set so if you time it right you might get down to the point where the converters have not set to ready but everything else has.
I got many of my friends cars to pass that way
Race Director
Joined: Apr 2007
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From: South Western Ontario
If you have a scanner then you might be able to slip in the e-test right between the other monitors setting and the codes appearing. Good luck.
Why not just pay the $150 or whatever it is for a mail-in tune and be done with the codes and CEL?
Why not just pay the $150 or whatever it is for a mail-in tune and be done with the codes and CEL?
Thread Starter
Pro
Joined: May 2012
Posts: 610
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From: La Plata Maryland
MD Events Coordinator
Thanks everyone for your help as always. Will keep you posted...
Melting Slicks
Joined: Jul 2012
Posts: 2,507
Likes: 9
It's the rear O2's causing your issue, they measure cat efficiency and you'll most likely NEVER pass without tuning out the rear O2's. As soon as you reset ANY code, all the IM monitors reset and you WILL FAIL.