Re-setting computer after adding performance mods? (long)

[24V-DSL]

Prior to buying my present truck I had a very bombed 97 Dakota gasser. Every thing except a super-charger.



I used to rely on the Dakota Mailing List site for info and sources. Just like the TDR.



The common practice was to "re-set" the computer after adding a performance mod, like adding hotter injectors, headers/exhaust, hot throttle body, etc. This was done to allow the computer to "re-learn" and adjust to the changes which would result from the new mod.



The practice was:



Disconnect the negative battery terminal.



Turn key to the START position and hold for 15 seconds.



Release key.



Reconnect the NEG battery terminal.



Start engine and let idle for about 1 minute.



Drive the truck for 35-50 miles to allow the computer to "re-learn" any new modification.



This theory did prove out to be accurate. Sometimes the truck seemed like a slug for up to 150 miles, like you actually had lost perfomrnace. Then, gradually, it would start to run stronger after "re-learning". This also applied whether you had the stock computer, or a Mopar Performance computer.



I've never seen anyone post on this issue on the TDR.



Does this have to be done for the diesels? For example, after adding DD2"s?



If not, why not?

 

[Todd T]

its a practice that will work on any ODBII or III system.



the idea behind it is to squeeze all you can out of the PCM



however if your truck is a manual. there isnt too many sensory inputs that would help the system "learn". but yes you could do it.



keep in mind, if you run hard all or most of the time, chances are you wont "feel" any changes... .



i just saw your truck is an auto, if you baby it around you could benifit by doing this. it will re-learn your shift habits and throttle pressures. the other thing to remember, is the OBD system does this for mainly one reason... . emissions... there are no sensors for oxygen content or otherwise on a diesel.



it is reffered to as a "Drive Cycle"

 

[24V-DSL]

Todd... . thanks.



I've heard it's a good idea to run hard up to redline occassionaly to keep you dialed in. I do it at least once a day.



Joe