In case you haven't read it and maybe want to try it.... here it is. I do not own the original rights to this procedure. I just cleaned it up and made it more understandable. ++Start++ SRT8 PCM Reset Technique..but should work on all LX vehicles. Step 1: Open the hood of the vehicle and open the covered fuse box on the passenger side of the vehicle. Step 2: Remove the following fuses and set them aside: 11; 14; and 16 These are labeled on the underside of the fuse box cover in a mirrored-layout fashion. Fuse 16 is a Dark-Blue 15amp fuse found on the far right of the box Fuse 14 is a Beige color 25amp fuse Fuse 11 is a Neon Yellow 20amp fuse Make sure to note the colors...the box lid with the fuse #s reads in reverse and can be confusing. Pay attention to the next key cycles and number of chimes in the following Steps! Step 3: Insert your key into the ignition and turn the key to ON. Wait for the initial sequence of lights and chimes to complete. Do not turn the key to 'Off' until you have reached Step 5. Step 4: Without turning the key to 'OFF', turn the key to the 'START' position and hold it there until you hear a single chime. The engine will not attempt to start, this is completely normal. After the chime, release the key from the 'START' position back to 'ON' without cycling the key. Repeat this step one more time, turning the key to 'START' and holding it until you hear the chime. Once the second chime has sounded, cycle the key back to the 'OFF' position and remove your key. Step 5: Return to the fuse box under the hood and reinstall the fuses, paying close attention to replacing the correct fuses to their original location. Close up the box, and start your car. You have now completely reset the PCM's adaptive memory, as well as cleared any stored Diagnostic Trouble Codes (DTC's). ************ Side Note: Some people have stated they have a Beige 25 AMP fuse for #11. Don't understand this..but. My Opinion: Using this procedure, my car seemed to perform a lot better than just the Fuse #11 pull. 1-2 shift was crisper and it felt stronger. ++END++
Sure. (Thats what we started with right?). When the PCM first initializes it starts out with some hard coded default values. It's even more than that. In the first half second it figures out what type of engine it is and then operates on more specific default values. (at least that's what the SRT Engineer said). EXACTLY! ...but for how long? ummm, errr, where did you hear this? anything (not anecdotal) to substantiate that? I've heard that sacrificing a chicken while doing that helps even more :erm:. Let me look up those fuses again.
Then the real quastion in the thread is...... if the adaptives are reset to terms that are better than where you were before the reset. Remember this problem will probably not exist if PCM is reset after repair of sensor or problem. I have been aware of this fact since I had a sensor failure (a fuel sensor, can't rememebr the name) that caused my own car (2002 Lincoln LSV8) run like crap (weak acceleration), the service guy (not a dealer service or they may have reset the PCM) told me it would take a couple of days for the car to "come back". Now if the PCM had been reset this probably would not have existed 'cause the tables would have been reset. A lot of codes are generated by sensor failures and not actual engine problems but the PCM doesn't know. I will look for the facts. I have seen references to this issue a few times before. It was also mentioned in the OBDII right up I linked to in an earlier post in this thread. "If the vehicle has been operated with a faulty sensor for any period of time, these learning tables will have been affected by the incorrect data. While the PCM will eventually correct the adaptive tables while the vehicle is driven, this may take quite some time." Now wait a minute, don't waist the chicken yet...... I don't want to have to put chicken blood all over my car when I may not have too. If it works, I will add this as a step to the procedure. Fuse #11 is involved so we know adaptives are effected. Maybe one of these fuses goes to the TCM so that may answer the shift improvement. Also all codes are cleared, so now we can also think of PCM or even TCM "counter measures", that have worked into the short and long term adaptives, that may have effected enigne performance.
Dynosteve said that it takes at least 3 consecutive WOT's (during the same warmup cycle) for a change in the tune to take full effect. This may shed some light on your discussion.
First things first. WHAT adaptives? Then, would reseting them be beneficial? Then, how long do they take to adapt? The answer for each adaptive (IF there are more than one) could be different.
Good question. I would assume, short-term and/or long-term adaptives, and maybe some non adaptive settings, like fault codes. Wait.... IS that what this thread is about?... What adaptives ARE reset? I thought it was about if it was beneficial to the car's performance or not. Depends on the condition of PCM information when reset. I have heard short term numbers anywhere from as soon as you start driving to 50 miles and long term numbers from 200+ miles. I don't think all the adpatives are really on the same time and/or distance table. Meaning short term adaptives and long-term adaptives. IMHO Certain information on a PCM reset would affect short term and long term adaptives and maybe some information that is not sdaptive. Regrettably I do not know what all is "Reset". Hopefully somewhere, on the Internet or in a service manual, we will find or someone will tell us FOR SURE what happens on a "PCM Reset". However this may some of the reasons we see this gains from the reset. During your work week you had been driving like a grand-ma in afternoon traffic all week and then stay home, and don't take the car out for some "exercise". Then on on a Saturday you go for a "romp" or "exercise" and you think you car doesn't have any throttle response.. Then you reset your PCM and go out and try some full throttle runs and hot shifting in "Auto-Stick". You will have a "hot street" programmed car...... till you start your next work week.
Also... Not all volatile data may be removed by a simple "#Fues 11" PCM reset. By the use of "Capacitor drain" (for supplying long term low power) some chips can maintain memory for years. That may be why there are different procedures for diffreent types of "Resets", kind of like the one I also posted.
It's just we are all busy and just don't have the time. This is part of the Java operating system program for my StMo. Here is the list of adptives in the PCM shown by Star Mobile. Misfire Adaptive Numerator Value Unmetered Air Area TPS Minimum Learned Voltage Idle Speed Adaption VCT Servo Values Engine Sync Values VCT Measurement Values Fuel Adaptives If you reset the TCM it will default to the factory program which is better. Simple cut the battery power to the TCM and memory is lost. Jeff
PULSE-WIDTH EQUATION Load Base PW Calculation Adaptives RPM MAP MAX RPM (X ) BARO (X) TPS (X) ECT (X) IAT (X) Sensed B+ (X) LT* (X) O2 (x) Short Long(X)Long Term =Injector Pulse Width After long-term adaptive information is stored in memory, it becomes part of the Base PW Equation,and is used under ALL operating conditions; hot or cold, open or closed loop. This is the injector pulse width algorithm
Fuel memory cells , 25 in total numbered C1-C25 C24 and C25 are idle cells C1-23 are set aside for various MAP's verses RPM's adjustments.
I got that part. Any idea how they get populated and especially how fast they move and how long it takes them to settle? It sounds like the long term fuel cells are populated directly from the short term adaptives. Short term adaptives are constantly incremented by a little bit until the a/f gets to about 15.3:1 and then decremented until the a/f gets to about 14.1:1 when it startes incrementing again, repeatedly. At some point the long term fuel adaptive is adjusted using the value of the short term fuel adaptive (+ or - depending on whether the fuel is being incremented or decremented). When does this happen? Is it periodic? if so what's the period? Is it checked against some set of conditions periodically and then updated only if the conditions are met?
It doesn't take long to populate after the engine goes into closed loop, a couple minutes. It constantly checks and adjusts, if you have a StMo go to the adaptives screen and inject propane in the air filter, it changes quick. Jeff
Cool. So that's one down. Not much point in resetting the PCM for the fuel adaptives. Even if you made significant changes to the intake path.
ill do it again when i get home, got it back from the dealer service and need to throw my tune back on the badgirl.
This first post on this thread is a great read. http://www.chargerforums.com/forums/showthread.php?t=71148&highlight=fuse+pull+reset+pcm
