Clearing computer?
Veteran
Joined: May 2007
Posts: 359
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From:
RE: Clearing computer?
I"m not going to pretend to know EXACTLY how it works, but I believe that the computer has parameters to learn different types of driving habits, based on TPS readins, Detent readings and Speed sensor readings. It probably takes an average of these, and adjusts the ECM accordingly.
With that being said, if you've owned your truck since new, I don't really see a reason to reset anything. How you drive, on an average, is how the truck will set itself.
My Silverado took almost 400 miles before the trans shifted consistently (although not a DC product) where it didn't vary any more.
My 2005 Grand Caravan took a few hundred miles as well.
The Ram took about 50-60 until decent shifting was noted, (less SuperChips) and about 200 miles till it was consistant.
Once I applied the SuperChips program (91 octane) it was within less then 20 miles till a difference was felt, on a regular, consistent basis.
With that being said, if you've owned your truck since new, I don't really see a reason to reset anything. How you drive, on an average, is how the truck will set itself.
My Silverado took almost 400 miles before the trans shifted consistently (although not a DC product) where it didn't vary any more.
My 2005 Grand Caravan took a few hundred miles as well.
The Ram took about 50-60 until decent shifting was noted, (less SuperChips) and about 200 miles till it was consistant.
Once I applied the SuperChips program (91 octane) it was within less then 20 miles till a difference was felt, on a regular, consistent basis.
Veteran
Joined: Jul 2007
Posts: 279
Likes: 2
From: montgomery,new york
RE: Clearing computer?
the only thing i'm scared of is i think i got a flutek,i mean ever since i got the truck(bone stock)it run alot better than other 4.7s,my boss had the samething an mine would smoke his by like two truck lengths,raced a few others an the same thing,well i guess it dosn't hurt to try
All Star
Joined: May 2005
Posts: 946
Likes: 1
From:
RE: Clearing computer?
Our pcm's learn as you drive, make no mistake about it.
The numbers are called adaptives. The adaptives that effect mpg are long term and short term fuel trims.
You need a scanner to read them.
The turbo and sc guys know more about that then they ever wanted too.
If you reset the pcm properly, you set the adaptives back to zero. Now the pcm learns all over again and makes adjustments as needed.
Our trucks run pretty much stoich (14.7 A/F) at idle and mid throttle, then richen it up for WOT. The adaptives that the pcm sets are what make that happen.
The numbers are called adaptives. The adaptives that effect mpg are long term and short term fuel trims.
You need a scanner to read them.
The turbo and sc guys know more about that then they ever wanted too.
If you reset the pcm properly, you set the adaptives back to zero. Now the pcm learns all over again and makes adjustments as needed.
Our trucks run pretty much stoich (14.7 A/F) at idle and mid throttle, then richen it up for WOT. The adaptives that the pcm sets are what make that happen.
All Star
Joined: Mar 2005
Posts: 752
Likes: 0
From: Tracy, CA
RE: Clearing computer?
on 04's an 05's, fuse 23 is the pcm, pull it out, then do the start thing as mentioned above...and NO, on 04's an 05's (i know these, not sure on others)..the truck will not start or turn on..just ding...I do this every once in awhile so that the pcm relearns...
All Star
Joined: Mar 2005
Posts: 752
Likes: 0
From: Tracy, CA
RE: Clearing computer?
try this trick, i do this when I go to the track...turn the key to the on position (dings, an dash light etc)...slowly depress the pedal all the way to the floor, hold for 10-15 secs, then slowly let off the pedal, turn key off..... this resets our fly-by-wire throttle. you instantly feel it respond quicker wen you push the gas...
Champion
Joined: Aug 2005
Posts: 3,313
Likes: 8
RE: Clearing computer?
It is my understanding that on 3rd Gen Ram engines
the two things that 'learn' are the short term and long term fuel trim memory registers,
and these work only during part throttle driving
as a 'speed up' to allow the oxygen sensor
get the air/fuel ratio into the 14.7 'window' faster.
Once you go above 80% throttle to wide open throttle
the PCM computer uses fixed tables to inject fuel and set ignition timing.
The above 80% throttle engine also stops being low pollution and can emit anything but black smoke....this "safety passing power" loophole in the Clean Air Act that has been defended from change by high senority Michigan Representive John Dingel from changes in the law is not well known by vehicle owners.
Bottom line: resetting your PCM computer will not improve your full throttle engine performance.
Resetting will make the air to fuel richer at part throttle and make the enigne seem 'smoother' for a short period until the PCM fuel trims 'learn' the correct values again...which they usually do within 20 minutes.
the two things that 'learn' are the short term and long term fuel trim memory registers,
and these work only during part throttle driving
as a 'speed up' to allow the oxygen sensor
get the air/fuel ratio into the 14.7 'window' faster.
Once you go above 80% throttle to wide open throttle
the PCM computer uses fixed tables to inject fuel and set ignition timing.
The above 80% throttle engine also stops being low pollution and can emit anything but black smoke....this "safety passing power" loophole in the Clean Air Act that has been defended from change by high senority Michigan Representive John Dingel from changes in the law is not well known by vehicle owners.
Bottom line: resetting your PCM computer will not improve your full throttle engine performance.
Resetting will make the air to fuel richer at part throttle and make the enigne seem 'smoother' for a short period until the PCM fuel trims 'learn' the correct values again...which they usually do within 20 minutes.
All Star
Joined: May 2005
Posts: 946
Likes: 1
From:
RE: Clearing computer?
QUOTE!
"It is my understanding that on 3rd Gen Ram engines
the two things that 'learn' are the short term and long term fuel trim memory registers,
and these work only during part throttle driving
as a 'speed up' to allow the oxygen sensor
get the air/fuel ratio into the 14.7 'window' faster.
Once you go above 80% throttle to wide open throttle
the PCM computer uses fixed tables to inject fuel and set ignition timing.
The above 80% throttle engine also stops being low pollution and can emit anything but black smoke....this "safety passing power" loophole in the Clean Air Act that has been defended from change by high senority Michigan Representive John Dingel from changes in the law is not well known by vehicle owners.
Bottom line: resetting your PCM computer will not improve your full throttle engine performance.
Resetting will make the air to fuel richer at part throttle and make the enigne seem 'smoother' for a short period until the PCM fuel trims 'learn' the correct values again...which they usually do within 20 minutes."
Hank,
That is a good write up. The WOT fixed numbers are preset in the pcm while its in 'open-loop'. It goes into open-loop somewhere in the 80 percentile throttle position area. In open loop, the pcm isn't even reading the o2 sensors or knock sensors.
"It is my understanding that on 3rd Gen Ram engines
the two things that 'learn' are the short term and long term fuel trim memory registers,
and these work only during part throttle driving
as a 'speed up' to allow the oxygen sensor
get the air/fuel ratio into the 14.7 'window' faster.
Once you go above 80% throttle to wide open throttle
the PCM computer uses fixed tables to inject fuel and set ignition timing.
The above 80% throttle engine also stops being low pollution and can emit anything but black smoke....this "safety passing power" loophole in the Clean Air Act that has been defended from change by high senority Michigan Representive John Dingel from changes in the law is not well known by vehicle owners.
Bottom line: resetting your PCM computer will not improve your full throttle engine performance.
Resetting will make the air to fuel richer at part throttle and make the enigne seem 'smoother' for a short period until the PCM fuel trims 'learn' the correct values again...which they usually do within 20 minutes."
Hank,
That is a good write up. The WOT fixed numbers are preset in the pcm while its in 'open-loop'. It goes into open-loop somewhere in the 80 percentile throttle position area. In open loop, the pcm isn't even reading the o2 sensors or knock sensors.
