PCM Reset & Emissions Testing

[ViperTony]

I had to disconnect my battery so I could clean the battery tray. In doing so, my PCM reset and apparently my emissions monitors/controls haven't kicked in yet. I tried to have my Viper emissions tested yesterday but they couldn't test because the monitors weren't 'on' yet. I've put on about 200 miles since the reset. I'm figuring 500 should do it. Generally, how many miles after a PCM reset does it take for the emissions controls to function normally again? - Tony

[SoCal Rebell]

Originally Posted by ViperTony

I had to disconnect my battery so I could clean the battery tray. In doing so, my PCM reset and apparently my emissions monitors/controls haven't kicked in yet. I tried to have my Viper emissions tested yesterday but they couldn't test because the monitors weren't 'on' yet. I've put on about 200 miles since the reset. I'm figuring 500 should do it. Generally, how many miles after a PCM reset does it take for the emissions controls to function normally again? - Tony

200 miles should be fine, your PCM should of "learned" by now. When reset it runs very rich to protect the motor and gradually leans out to the proper 13 to 1 or so as you drive.

[ViperTony]

Originally Posted by SoCal Rebell

200 miles should be fine, your PCM should of "learned" by now. When reset it runs very rich to protect the motor and gradually leans out to the proper 13 to 1 or so as you drive.

What I found interesting is that my AFR is actually leaner until WOT. Before the reset, my AFR gauge read around 14.7 - 13's during normal cruising. It's now between 14.5 and 15.1. WOT pulls fall within the normal AFR range I tuned with the Vec3. I think the PCM is still learning. Last fall, Chuck Tator reset my PCM using the DRB tool which I believe reset the adaptives. Since then, I haven't driven the Viper enough for the PCM to adjust. So I think it has some learning to do and I'm happy to put on as many miles as it takes to help get it there.

[ruckdr]

Next time try this:
COMPUTER MEMORY SAVERS - JCWhitney Replacement auto parts Parts

or this:
Vehicle Computer Memory Saver

or several other brands.

I have used this to change out my battery.
Got down to the point of disconnecting the battery, plug the thing in, and change out the battery. I even had time to run to the auto parts store. ALL functions are retained.

Later,

[ViperTony]

Thanks Don. Definitely something to keep in the tool box. - Tony

[RTTTTed]

Or just use Jumper cables and another battery hooked up at the front, then be carefull of the positive Bat terminal.

Ted

[ViperTony]

Well, after about 400 miles of driving after the battery disconnect the emissions testing place still couldn't get emissions info from the PCM so we had to roll and sniff. It passed.

[dave6666]

Did this finally resolve itself?

[ViperTony]

Yes...I drove around for another week and put on 500 miles. Just over 700 miles after the PCM reset. Went back to the shop but they still couldn't get any emissions information from the PCM through the OBDII port. So they sniffed the pipes instead and it passed. I believe I was well within the emissions parameters. Not sure why the PCM isn't cooperating with the emissions equipment. It may be this particular shop but they're the only one I trust to test my Viper.

[viperdude118]

For whatever reason this subject in regards to OBD II systems is fairly misunderstood. I wish I had a dollar for everytime some came into our emissions station and left pissed off and yelling at us because the IM monitors had not reset and we could not perform the test on their vehicle. I have seen it a million times.

Every vehicle manufacturer along with every OBD II vehicle has somewhat specific criteria for resetting the IM monitors to the "ready" state. Some vehicles are more particular then others. I remember for instance some of the Ford vehicles required a minimum of 40 degrees F for the evaporative system to conduct its test. Well in Ohio in the winter sometimes several weeks may go by without the temps reaching 40 F.

Basically cars run anywhere from 4 up to 10 (usually 8) self diagnosing tests, the tests require different but specific criteria to be met. If the criteria is met, then the monitor for which the test is being done sets itself from "not ready" to "ready".

Some examples I recall are driving approximately 55 mph for 7 consecutive min, coolant temp reaching 190 F, minimum of 12 cold starts. These are just a few. Every manufacturer is different and specific to that brand.

There is no minimum mileage that automatically sets these monitors.

Also depending on the state in which the emissions tests are being conducted and depending on the year of the OBD II vehicle, not all monitors necessarily have to be set for testing to be done. Some of the early OBD II's like 96's and 97's only required like 2 monitors to be set. The Catalytist monitor was always one of them.

Hopefully this gives a slightly better idea to everyone on what is up with these inspection monitors.


Additionally, slow easy starts and easy deccelerations seemed to help in certain monitors setting. Not always an easy task in a viper.

[ViperTony]

Originally Posted by viperdude118

For whatever reason this subject in regards to OBD II systems is fairly misunderstood. I wish I had a dollar for everytime some came into our emissions station and left pissed off and yelling at us because the IM monitors had not reset and we could not perform the test on their vehicle. I have seen it a million times.

Every vehicle manufacturer along with every OBD II vehicle has somewhat specific criteria for resetting the IM monitors to the "ready" state. Some vehicles are more particular then others. I remember for instance some of the Ford vehicles required a minimum of 40 degrees F for the evaporative system to conduct its test. Well in Ohio in the winter sometimes several weeks may go by without the temps reaching 40 F.

Basically cars run anywhere from 4 up to 10 (usually 8) self diagnosing tests, the tests require different but specific criteria to be met. If the criteria is met, then the monitor for which the test is being done sets itself from "not ready" to "ready".

Some examples I recall are driving approximately 55 mph for 7 consecutive min, coolant temp reaching 190 F, minimum of 12 cold starts. These are just a few. Every manufacturer is different and specific to that brand.

There is no minimum mileage that automatically sets these monitors.

Also depending on the state in which the emissions tests are being conducted and depending on the year of the OBD II vehicle, not all monitors necessarily have to be set for testing to be done. Some of the early OBD II's like 96's and 97's only required like 2 monitors to be set. The Catalytist monitor was always one of them.

Hopefully this gives a slightly better idea to everyone on what is up with these inspection monitors.


Additionally, slow easy starts and easy deccelerations seemed to help in certain monitors setting. Not always an easy task in a viper.

Hmmm...well, this is the second time that the monitors weren't ready. This also happened to me 2 years ago. The day of testing, I had put on about 75 miles, mostly cruising, before I got to the test center. Coolant temp was 195, outside temps in the 70's. I had many cold starts, different driving conditions during the 700 miles or so leading up to the test. I think your explanation makes sense but I'd like to know specifically how the Viper emissions monitors work.

[dave6666]

Originally Posted by ViperTony

...but I'd like to know specifically how the Viper emissions monitors work.

Double Top Secret Tony.

[ViperTony]

Originally Posted by dave6666

Double Top Secret Tony.

Blasphemy! I must crack this code.

[viperdude118]

Originally Posted by dave6666

Double Top Secret Tony.

Here is part of the secret maybe. I can't see a viper pcm having anything different than other chrysler products.

What are the readiness monitor run conditions? - SRT Forums - SRT4, SRT6, SRT8, SRT10 & Dodge Forum