Evaporative System Test
Thread Starter
TECH Enthusiast
Joined: Apr 2003
Posts: 561
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From: silver Spring MD
Evaporative System Test Hi Folks,
I followed GM recommendations ran thru the driver steps to complete all the tests - 55mph, coast to 20 mph, etc. The one that I have not seen say complete is the "evaporative system" test. I am setting not codes and the none of the evaporative fail codes are disabled.
How long (CYCLES) does it take to clear that test?
Thanks
Bill
I followed GM recommendations ran thru the driver steps to complete all the tests - 55mph, coast to 20 mph, etc. The one that I have not seen say complete is the "evaporative system" test. I am setting not codes and the none of the evaporative fail codes are disabled.
How long (CYCLES) does it take to clear that test?
Thanks
Bill
Teching In
Joined: Aug 2005
Posts: 20
Likes: 0
From: Avonmore,PA
I ran into that problem with my 97 Grand Prix. I believe the outside air temp wasn't high enough for the test to run. As soon as it warmed up to about 50 degrees, the test finally ran and passed.
Enhanced Evaporative Emission tests may be performed by the vehicle's module when specific conditions are met. These conditions are determined by the calibration within the module. These calibrations are vehicle platform and engine family specific. When the key is turned to the start or run position, the module checks the output of various sensors on the vehicle to determine when and if the Evaporative Emissions tests should be run. Refer to Engine Controls sub-section of the appropriate Service Manual for specific DTC information.
Some of the most widely used parameters are listed below:
1. The Barometric Pressure (BARO) is greater than a specified kPa (psi).
2. The system voltage is between 10 and 18 volts.
3. The intake air temperature (IAT) is within specified temperature values.
4. The engine coolant temperature (ECT) is within specified temperature values.
5. The ECT and IAT are within specified temperatures of each other when the vehicle engine was started.
6. The fuel level sensor indicates the fuel level is greater than a specified % of empty and less than a specified % of full. (For a 76 L (20 gal) fuel tank, a fuel level of more than 11 L (3 gal) but less than 64 L (17 gal) or as specified in the calibration).
7. Some platforms such as the Alero and Grand Am, use a miles driven check as well.
Enhanced Evaporative Emission tests may be performed by the vehicle's module when specific conditions are met. These conditions are determined by the calibration within the module. These calibrations are vehicle platform and engine family specific. When the key is turned to the start or run position, the module checks the output of various sensors on the vehicle to determine when and if the Evaporative Emissions tests should be run. Refer to Engine Controls sub-section of the appropriate Service Manual for specific DTC information.
Some of the most widely used parameters are listed below:
1. The Barometric Pressure (BARO) is greater than a specified kPa (psi).
2. The system voltage is between 10 and 18 volts.
3. The intake air temperature (IAT) is within specified temperature values.
4. The engine coolant temperature (ECT) is within specified temperature values.
5. The ECT and IAT are within specified temperatures of each other when the vehicle engine was started.
6. The fuel level sensor indicates the fuel level is greater than a specified % of empty and less than a specified % of full. (For a 76 L (20 gal) fuel tank, a fuel level of more than 11 L (3 gal) but less than 64 L (17 gal) or as specified in the calibration).
7. Some platforms such as the Alero and Grand Am, use a miles driven check as well.
If youre taking it in for an OBD-II inspection, just disable all DTC's and upload the bin right before you go to the tuner. All the readiness bits will complete immediately. If you wern't getting a code, what are the chances youll throw one on your way there. Reflash on your way out of the inspection station! 
Thread Starter
TECH Enthusiast
Joined: Apr 2003
Posts: 561
Likes: 0
From: silver Spring MD
Originally Posted by GuitsBoy
If youre taking it in for an OBD-II inspection, just disable all DTC's and upload the bin right before you go to the tuner. All the readiness bits will complete immediately. If you wern't getting a code, what are the chances youll throw one on your way there. Reflash on your way out of the inspection station!
have you done this before? if there is no risk, why not reflash at home vs doing it before and after the inspection at the station?
thanks
Bill
I just did it saturday. Set all the pertinant DTC's to no error reported and all the systems auto completed. Then I drove to the inspection station and passed with flying colors. the guy was very impressed cause he knew what was up, so i was showing him the software. Then after i got my sticker I drove home and flashed to my last bin. You can drive around as long as youd like with all your DTCs turned off, but you wont know if you actually throw a code.
I went to a guy I knew through a friend, since I have heads and cam, dont have cats, or air, or PCV, or just about any other emissions. You had to see everyone's face when they saw it pass without the slightest problem. Everyone was scratching their head as the car sat lumping away shaking like a paint mixer and spitting raw fuel out the pipes.
I went to a guy I knew through a friend, since I have heads and cam, dont have cats, or air, or PCV, or just about any other emissions. You had to see everyone's face when they saw it pass without the slightest problem. Everyone was scratching their head as the car sat lumping away shaking like a paint mixer and spitting raw fuel out the pipes.
Last edited by GuitsBoy; Mar 20, 2006 at 07:56 PM.
Ha ha yeah I did the same thing last week, but the inspectors didn't know what was up. One of them did ask what I had done to the engine, though. He didn't question me any further when I said I had only done a few minor engine mods and concentrated mostly on weight reduction for autoX. That 235/240 cam sure weighs a lot less with the smaller than stock base circle 
Now if I could just get rid of that raw fuel exhuast stink it would be a little less obvious . . .
Now if I could just get rid of that raw fuel exhuast stink it would be a little less obvious . . . Trending Topics
Originally Posted by Cal
Ha ha yeah I did the same thing last week, but the inspectors didn't know what was up. One of them did ask what I had done to the engine, though. He didn't question me any further when I said I had only done a few minor engine mods and concentrated mostly on weight reduction for autoX. That 235/240 cam sure weighs a lot less with the smaller than stock base circle Now if I could just get rid of that raw fuel exhuast stink it would be a little less obvious . . .
Now if I could just get rid of that raw fuel exhuast stink it would be a little less obvious . . .LS1 Tech Stories
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Here in North Carolina the OBD2 test can have one readiness code not complete and still pass for 2001 and up, and 2 codes not complete for 2000-1996. I assume Maryland would be similar, there is also an "evap-specific" drive trace that you can do, I don't know where to find it on-line but I know its on our computer at work and I can post it tomorrow if I remember.
