ECM's that need to "re-learn"

HLN A55

HLN A55

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You know I really don't get this concept that if you don't run your car for a while that you need to allow the ECM to re-learn or get used to something... I mean really.. What would it forget??? even if the battery was dead, I'm sure that there are no flash memory components of the ECM that would get wiped if the battery were to die..

Can someone explain this??
 
HLN A55 said:
You know I really don't get this concept that if you don't run your car for a while that you need to allow the ECM to re-learn or get used to something... I mean really.. What would it forget??? even if the battery was dead, I'm sure that there are no flash memory components of the ECM that would get wiped if the battery were to die..

Can someone explain this??
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Never heard of this at all .
 
I always hear about this nowadays. I'm told the ECM will adapt its programming to meet changing operating conditions. It's reset when the battery is disconnected. I'm not sure what it's "learning" though. You'd think it would just adapt?
 
Adaptive strategy systems can actually learn from past experience,it can adjust based on driving habits ambient conditions and for fatigue of vehicle components. When a computer has been disconnected removed or replaced there will be a short re learn period approx 5 miles of driving,during this time you may notice a surge or a high idle,loss of power. Most strategies have two parts long and short term fuel trim. Short term is the one more affected
by this interruption of power and the long term is based on input from the short term. On older vehicle systems OBD1 you had to follow various re learn procedures that usually involved the checking or adjustment of various sensors. On later model vehicles the procedure is simply drive cycles,ie the first 5 mile trip is usually enough time to make any noticeable adjustments unless major changes have been made to the engine,then you better go see Manny@ECP
 
taylorsk8 said:
And I thought my carb was picky. At tleast it doesn't reset when I disconnect the battery!

T
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HA! Won't that be funny if the carb had to adjust it's venturies every time it drove...that would be kind of cool too.

That is one thing I like about the Chevelle is that 90% of things can be fixed/diagnosed with a 1/2" or 9/16" wrench and a test light. You guys that understand computers and ECM's amaze me.
 
Riely,did not know you had a Chevelle! What year and model?
 
'66 Malibu SS. It has a 396 and 4-speed. Very good shape but could use some new stuff such as interior, full wiring harness, wheels, tires, etc. But good enough to drive and make noise with. It saves the Vette from abuse.

No ECM yet... although it would be nice to update to a new engine, I just really like how the old one sounds.
 
Riley P said:
'66 Malibu SS. It has a 396 and 4-speed. Very good shape but could use some new stuff such as interior, full wiring harness, wheels, tires, etc. But good enough to drive and make noise with. It saves the Vette from abuse.

No ECM yet... although it would be nice to update to a new engine, I just really like how the old one sounds.
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Does not sound like beater,more like a potential dream machine.
 
Riley P said:
'66 Malibu SS. It has a 396 and 4-speed. Very good shape but could use some new stuff such as interior, full wiring harness, wheels, tires, etc. But good enough to drive and make noise with. It saves the Vette from abuse.

No ECM yet... although it would be nice to update to a new engine, I just really like how the old one sounds.
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All this and still no pics of this ride??? It's not like it's a Mustang!!! Post up boy!!!
 
rchevelle.jpg
 
Nice Ride.

I think the PCM have Ram (volatile) and Rom (non-volatile) and tsop (non-volatile) memory and maybe eprom (non-volatile).
There are a few in there, some old computer used to have a base settings for the MAF, injectors etc.
The PCM had the ability to learn the driving conditions and self monitor itself and do some adjustment
to compensate for more airflow etc.
This info was then stored in RAM and which is volatile so if power is lost the data is lost also and the system must relearn again
to compensate for any changes that took place over the original data.
When you flash with EFI or HP tuners they are updating the TSOP with the changed data, this is written to the chip that will
will not be lost with power removed.
 

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