it stores memory for about 50 key cycles.

to help it learn... be gentle on the gas pedal.
slow acceleration is the computers friend.

flooring it does nothing.

 

Don't worry, I couldn't afford to floor it too many times with gas prices being what they are.

 

It only takes ~30 seconds for the computer to relearn its settings. Generally it'll idle high during that time (at least on WJ's) until it learn them.

 

So is there anything odd about what it's doing? Even when the old PCM was shorting out and resetting continually it didn't do this as far as I noticed. I've heard about all kinds of weird stuff going on until the things adapt with time.

 

When I had my batt problem it was relearning every time I got her started and it took a different amount of time every time.

 

Idle and things like that are set within the first few minutes.

The fuel trims, adaptive strategies, among other things are what take a while to learn. The PCM after a while learns to trust and distrust sensors based on feedback it receives compared to information stored from previous readings. If for some reason a sensor suddenly goes way off, the PCM will eventually stop trusting it..and instead of tuning the engine around a faulty sensor reading and harming the engine and driveability; the PCM will replace the sensor reading with a best guess from a past memory. When the PCM is learning, there ARE no or few past memories.. hence why sometimes the car takes a while to start running correctly again.

 

Oh boy a PCM thread.

Ive gotten balls deep in this one before!

I would assume you disconnected the battery to do this, if so you also reset the TCM at the same time. So while your PCM is learning right now so is the TCM to provide smooth shifting based on your driving habits. Between the both of them give it a little time and it should adjust itself back to normal.

What Sgarlic is describing above are the "open and "closed" loop modes of the PCM.A normal running vehicle will see both modes every day!

When you start your vehicle you will be in "open loop" untill you reach normal temp(also why o2 sensors have heater elements, so you can enter closed loop sooner). This is where your PCM is running Preprogrammed FIXED values.

As soon as the PCM can see that temps are up it will switch to closed loop. Now your pcm in monitoring all the sensors and making adjustments based on the feedback.

Now when a sensor fails, the PCM will throw itself back into open loop running between fixed values and what it can read from the other sensors.Depending on what failed determines what set values it will use and what sensors it will still listen too.

The memory comes into play with driving habits and the wear on the vehicle.When a vehicle rolls off the floor it needs to be broken in. It will consume more fuel and after a while will get better. 150k later its back to using more fuel due to wear. Not to mention half the morons out there that dont take care of thier vehicles.

So the PCM saves the info on the running condition and any adjustments it had to make for it to run well.This way everytime you start your vehicle its not starting the process over again and any adjustment should me minor.

 

Thanks for the info, I knew about the closed/open scheme, but not in that detail.

Mainly I'm just wondering whether this slowing/bogging deal is something the computers will pick up, or whether it's a sensor/electronic issue.

 

Thanks for the info, I knew about the closed/open scheme, but not in that detail.

Mainly I'm just wondering whether this slowing/bogging deal is something the computers will pick up, or whether it's a sensor/electronic issue.

I believe it will, when I reset the computers on my Intrepid the same thing happens.Come to a stop and the tach drops-picks up and the levels off to normal Idle.