Here is a question for ya'll that I have wondered about. In doing some reading here of older threads, especially those in the Engine Forum, there is a notion that the ECU (Engine Control Unit) or computer has some sort of heuristical learning capability.

Exactly what does it learn or memorize? From the readings, there appears to be a so called "factory Setting" and then the unit tends to auto-magically vary from that based upon what?

Is it driving style?
Is it engine settings?

Just curious to know.

 

i believe it is driving style. When ur car came form the factory, the engine ECU, was preset with the factory settings. These factory settings are not tuned for fast paced driving, but are for the daily driver and r tuned to save gas, etc. When, however, the ECU is reset, all of the settings r erased and new ones musty be made. This is why a lot of people here (including me) have reset their engine ECU's. When they reset, the driving style next will program them. For example: when u reset ur ECU, u want to go out and drive as fast and sporty as u can, b/c then the engine ECU will have a better shifting response, etc. It will anticipate ur sporty driving, and the "think" time to switch gears will not be as long. Hope this helps.

PS: This was just for the engine ECU. Ur SC is equipped w/ many ECU units: engine ECU, Fuel Pump ECU, etc., etc.

 

Do you reset the ECU by disconnecting the battery? I have a 1996 ES300, please let me know.

Thanks

 

I have a 92 SC300 Service manual. From the functional description the ECU is not a learning computer.

The ECU controls the following functions:

1. Electronic Fuel Injection (EFI)

The ECU receives signals from various sensors indicating changing engine operation, conditions such as:
intake air volume
intake air temp
coolant temp
engine rpm
acceleration/deceleration
exhaust oxygen content etc.

The signals are utilized by the ECU to determine the injection duration necessary for optimum air-fuel ratio.

2. Electronic Spark Advance (ESA)

The ECU is programmed with data for optimum ignition timing under any and all operating conditions. Using data provided by sensors the ECU triggers the spark at precisely right instant.

3. Idle Speed Control (ISC)

4. Diagnosis Function

When the ECU detects any malfunction or abnormalities in the sensor network, it lights the "Check" engine warning light

5. Self-Correction Function

If any sensor malfunctions an average value recorded in the back-up circuit is substituted to make driving possible

6. Fail-Safe Function

Even if an abnormality occurs in the ECU, the back-up circuit uses a specified fuel injection and ignition timing to provide vehicle driveability.

I dont think that describes a learning computer. I dont know if its the same type ECU on the 400 or if the type of ECU was changed with the new VVT-i

hope this helps


gadgetSC

 

Thanks gadge,

That info is awesome.

 

i dunno, but it did something (on the positive end) when i reset it in my 92 SC3. To reset it just disconnect the battery for like 15 min., and then go out and drive like uve never driven before. It might help on the ES but it might not be as drastic as in the SC just b/c the ES is not meant to perform (shifting, etc.) quiet as sporty as the SC is to. Hope this helps though.
PS: whe u disconnect the battery, it will reset all ur preset functions (radio, steering wheel, seat memory, etc.)

 

I like to take slow takeoffs and drive around 45 to 50 MPH on the highway, on normal streets i drive 30MPH. I use 93 octane Exxon gas and put in The outlaw fuel injector cleaner developed by Pennzoil

 

Erfan...in that case...no need to mess w/ ur ECU.

 

Thanks for the info.

 

I don't know exacly what it learns but I have found out that I need to reset my ECU often. I have a fuel controler (Apexi S-AFC) and the ECU rethards the timeing with S-AFC running. So I need to reset the ECU so I get the full power.