Hi all, i'm still here (in spirit)

I read around and find many owners doing normal maintenance on their LRs, (I can only relate to the '90s D1 & P38), only to have it run crappy or throw codes.

I've been told by numerous sources (including LR tech) that the ECU develops memory of operating parameters over time.

If we disrupt those parameters - i.e. changing bad plugs, wires, clean maf, stepper, or
GOD FORBID,the ECU, then the ECU has to relearn.

I did my fair share of tuning on my P38 & don't remember throwing a code except for the trans (engine died while coasting in gear) - it cleared the next day.

I've done more than my fair share on my '97 D1, thrown more codes, but they either
cleared or I cleared them.

The stepper was a PITA, but after several weeks with the new one, it started settling down.

Any thoughts? (based on facts)

luck, greg

 

All engine management systems have a rolling memory.
It works like the caller ID on your phone, call 20 is erased when a new call comes in.
If you take a 500 mile trip on the expressway then the ECU will run the engine off of the expressway trip the next time you start it.
But then start driving in the city again and then the city parameters start coming into play.
The ECU takes a average of the last 400 miles driven to keep the engine running at optimal efficiencies for your type of driving.
So if you always floor it when taking off from a red light then even when you try and drive it gently it will dump in more fuel than needed because it assumes that you are going to floor it at any time.
This is one of the reasons that some cars had coded ignition keys, they key stores that drivers driving habits and tunes the ECU for that driver.
When I had my Infinity I drove it pretty hard, my wife did not.
If I drove to the store using her key I could tell the difference in the way the car drove.
This is true for all fuel injected engines.
If you have a electronic transmission like on a DII or a P-38 then the trans ECU does the same thing.
It will hold the up shifts longer if you are the jack rabbit driver even when you try and drive slow.