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.

 

Yeah, you can't clear the codes just before a test. Just drive it a few days and go back. You should be fine.

 

If you clear the codes then get tested, you will not have gone through enough start-run-stop cycles to get the emission related diagnostics to the ready state. If too many of them are not ready then it will fail.

 

Thanks for the reply. I will try in a few days.

 

I just went through exactly this today and had no problem passing emissions. I had the same tests in the Not Ready mode so I did one driving cycle as prescribed by GM and went straight to the testing station and passed. I didn't even have to go through the exact cycle to get the tests to register correctly. The reason my system readiness was in that condition is that I had to load a previous tune with EFI Live when I drove my car to Indiana when I moved here and hadn't had time to drive it to get the SRT in the correct form for the emissions test. Took all of 15 minutes of driving to get it to pass. Here's the driving cycle I did most of:

General Motors' OBD-II driving cycle

• Cold Start. In order to be classified as a cold start, the engine coolant temperature must be
below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at start-up. Do not
leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.

• Idle. The engine must be run for two and a half minutes with the air conditioner on and rear
defroster on. The more electrical load you can apply the better. This will test the O2 heater,
Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.

• Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until
88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics
will be performed.

• Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time
the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.

• Decelerate. Let off the accelerator pedal. Do not shift or touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.

• Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same
diagnostics as in step 3.

• Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be
performed. If the catalyst is marginal or the battery has been disconnected, it may take 5
complete driving cycles to determine the state of the catalyst.

• Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or
brakes or shift gears.

 

Thanks for the info. I will follow the GM driving cycle and see if I can pass the test.

 

Sorry to hijack the thread, but this is sort of related....I just bought a Tech2. does anybody have experience with these that can suggest what things to check, clear, set prior to a smog test?
Thanks
John