St. Louis Emissions (Failed test)

jjk2509 · 02-25-2006, 05:45 PM

I recently moved to St. Louis and had my 98 tested for emissions. I had my car tuned after new heads, cam and LG headers with hi-flow cats. The tuner turned off the oxygen sensor codes. I check my codes before the test and I had no emissions codes. I then cleared all codes.

The test with the OBD showed the follow as not ready:
Catalyst
Evaporative System
Oxygen Sensor
Oxygen Sensor Heater

EGR System - Not Supported

Readiness - Failed

The technician informed me that the car failed and told me the computer codes were cleared and or the car needed to be driven larger so the computer could generate new information for the test.

He told me to drive the car for a few days and come back to be tested.

Does anyone have any suggestions on what to do? The tuner turned off some codes. Will I have problems?

Thanks in advance for any help.

Riks40th · 02-25-2006, 05:58 PM

I can't help you on your problem, I'm sure someone will chime in soon. If your going to need a mechanic, Bill at Elco Chevy is the man on C5's.
I just wanted to welcome you to St. Louis.

If your looking for a local club to check out, look into http://www.route66corvetteclub.com/, we have alot planned for the summer, so if your looking for something to do or people to meet then look us up.

Rik

http://photobucket.com/albums/y126/Riks40th/

yankee0304 · 02-25-2006, 06:22 PM

Quote:

Originally Posted by jjk2509

I recently moved to St. Louis and had my 98 tested for emissions. I had my car tuned after new heads, cam and LG headers with hi-flow cats. The tuner turned off the oxygen sensor codes. I check my codes before the test and I had no emissions codes. I then cleared all codes.

The test with the OBD showed the follow as not ready:
Catalyst
Evaporative System
Oxygen Sensor
Oxygen Sensor Heater

EGR System - Not Supported

Readiness - Failed

The technician informed me that the car failed and told me the computer codes were cleared and or the car needed to be driven larger so the computer could generate new information for the test.

He told me to drive the car for a few days and come back to be tested.

Does anyone have any suggestions on what to do? The tuner turned off some codes. Will I have problems?

Thanks in advance for any help.

The guy at the test center is correct-you will need to drive your car for a longer period of time to get those readiness tests completed. The EGR shouldn't be a factor in this case-if it's not supported, they can't test it. I'm not exactly sure how much your tuner had to do or change in the computer's programming, but if there is an issue that is still there, you'll still get one, if not all, of the same codes that were present the last time the light was on. One note on the evaporative system, and I know this is very basic and I don't mean to insult your intelligence, but make sure the gas cap is tight-the best way to know that it's tight, with Ford being the only exception I know of, once you here three clicks while tightening, you know that the gas cap is tight. That's not the only issue that could cause an Evaporative emissions code, but it's the cheapest and easiest possible cause to fix.

In regards to the Oxygen Sensor and the Oxygen sensor heater circuit, I'd almost be willing to bet that they are for the same oxygen sensor, but since I don't have the exact codes in front of me, I cannot say for sure. In my own personal experience with GM's O2 sensor heater circuit codes (they are electrically heated-it takes too long for exhaust gasses to get hot enough to do this on their own, so the extra help gives them the ability to get into closed loop-the fuel efficient way of running), if one should be set, it most likely means that the particular sensor that gave off the code is shot and should be replaced. I haven't been wrong yet in replacing one with a code of this nature, but there's always room for a first, which is why I'd like to see the codes for the 02 sensors. There may be more to this picture than I am seeing, and I don't want to find myself going down the wrong path in trying to help you.

I'm going to take this one step further just for the sake of conversation, and no more. Should the dead oxygen sensor (not the one with the heater problem) be after a catalytic converter, that would be the most probable cause of the cat code.

With all of that said, I don't think I can be of much more help at the moment.

-Brendan

lspalding · 02-25-2006, 08:21 PM

It's true that you have to drive the car in varying conditions so that the system can check everything and give a 'ready' response when checked. You can't clear the codes just before the test and pass. I had a random misfire code stored in my dd, which I cleared by disconnecting the battery. Drove the car to work for a week before the test and passed just fine. If you can't drive the car for a while without getting codes you are f**ked.

VetteTech81 · 02-26-2006, 08:29 AM

Quote:

Originally Posted by jjk2509

I recently moved to St. Louis and had my 98 tested for emissions. I had my car tuned after new heads, cam and LG headers with hi-flow cats. The tuner turned off the oxygen sensor codes. I check my codes before the test and I had no emissions codes. I then cleared all codes.

The test with the OBD showed the follow as not ready:
Catalyst
Evaporative System
Oxygen Sensor
Oxygen Sensor Heater

EGR System - Not Supported

Readiness - Failed

The technician informed me that the car failed and told me the computer codes were cleared and or the car needed to be driven larger so the computer could generate new information for the test.

He told me to drive the car for a few days and come back to be tested.

Does anyone have any suggestions on what to do? The tuner turned off some codes. Will I have problems?

Thanks in advance for any help.

I'm not sure if you will have problems if he turned codes off..
I am guessing he turned off the Rear O2 Codes?

If there were no emissions codes why did you clear all codes?

When you clear codes.. you also clear out the monitors that the test looks for to pass emissions and you have to wait till they run and pass before you go back to the testing center...

Note on EGR as I'm sure most know this.. The system is not supported because 97-up vettes do not have an EGR valve..

BTW: I learned something interesting on some vehicles the rear O2's effect the fuel trim I was shocked to hear/learn this in one of my classes yesterday. I guess they do this to protect the cat if they see a rich condition to lean it out ect.. its crazy.. not all cars are like this but some are the instructor/technician conducting the class showed an experiment with a signal generator in place of the rear O2 showed the fuel trim and pattern for the up stream O2 produced a lean condition on the REAR O2 with the signal generator and watched the UPSTREAM O2 show the exhaust was going rich. There is a percentage that the rear O2 does effect the fuel trims.. but again this is not on all cars but on many newer cars.. I wonder what happens when people start running hi flow cats, test pipes, and O2 sims on the rear of these cars..

Anyway there is only one way to find out if YOU are going to have an issue with passing.. DON'T clear the codes if non are set.. drive it.. highway local put some miles on it.. maybe have another non emssions tech like a local shop plug it and check to see if the monitors have ran and passed... I think here in IL you can have 2 monitors that have not ran and passed not 100% on this at the moment..

GOOD LUCK...
-=Rick

jjk2509 · 02-26-2006, 11:11 AM

I checked my codes to see if I had any emission problems, I did not.
I then cleared the codes I had without knowing this would mess up the test.

I guess you learn something new every day.

I will get retested on Monday.

Thanks for all of the help.

yankee0304 · 02-26-2006, 07:05 PM

Quote:

Originally Posted by VetteTech81

I think here in IL you can have 2 monitors that have not ran and passed not 100% on this at the moment..

Rick,

I've heard the same info about our tests here, but for some reason I thought it was three, but I believe that you have the correct number.

yankee0304 · 02-26-2006, 07:05 PM

Quote:

Originally Posted by jjk2509

I checked my codes to see if I had any emission problems, I did not.
I then cleared the codes I had without knowing this would mess up the test.

I guess you learn something new every day.

I will get retested on Monday.

Thanks for all of the help.

Let us know what happens.

GTENIT · 02-28-2006, 02:55 AM

I Thought All They Did Was A Sniffer Test. Glad I Dont Live In St Louis. Would Have To Get A Po Box Out Of Town

plaster · 02-28-2006, 10:41 AM

Quote:

Originally Posted by GTENIT

I Thought All They Did Was A Sniffer Test. Glad I Dont Live In St Louis. Would Have To Get A Po Box Out Of Town

They don't do a sniffer test, unless they do not have enough info from the scan or your light is on.

No way my car can pass at the pipes, but I kept throwing codes. HAd to get the thing retuned (pretty modified), and there was still a code that woul dcome on. Even though they tested my cap, I got a new one and now the light rarely comes on.

DO NOT go to O'Fallon station - apparently have never lifted a Corvette hood and asked me where my air pump was - I said 'shouldn't you know that? I just bought the car last week!'