ECU RESET, HOW LONG DOES IT TAKE? HOW TO TELL ITS COMPLETED

How long does it take for the ECU to reset?

I have read lots of info from 100-500 miles and certain driving conditions.

With that said is there a way to know when it ACTUALLY is reset more importantly?
How can one know when it’s completed the leaning period

 

What do you mean reset?

Are you talking about the emissions readiness?

For that you need to have an OBDII code reader. I have one that's bluetooth and connects to my phone via the Torque Pro ap.

You can setup a screen like this:

 

If you disconnect the battery clearing the memory the ram so the ECU has to reset itself how do you know it has reset and relearned the bell curve and the maps

 

Does anyone have any documentation on this learning that the ECU supposedly does? There's a little voice in my head that says we're making a bigger deal of it than it deserves.

 

I believe those constantly change based on driving conditions anyway, but I'm pretty sure those get "relearned" within a few minutes. The emissions take a while longer but as long as you know what the exact drive conditions are, hat can be done in a few minutes. Generally, if you drive around normally for a day or two, it sorts itself out without you ever noticing.

The only reason it matters to know exactly how long that takes is if you have to get the vehicle smogged in the morning (like what happened to me after I did my timing belt).

 

I would imagine by the time the OBD2 compliance readiness shows complete that the the ecu has pretty much 'mapped out the fuel stuff'. I think the big thing is to disconnect the power so that the remapping is quicker than if you didn't remove power from ECU, so the ECU isn't factoring the old data from the old sensors into the equation. If that's even the way it works. Kinda the way I picture it in my head

 

i have enough on my plate as it is! ... what else is going to go wrong on my truck

 

The key to driving an older vehicle is knowing what problems you can safely ignore.

 

And knowing how to determine what is an actual problem vs a fake problem we create in our minds

 

ECU learning ? Yet to experience said event. Sounds hinkey to me also.

 

Given the technology in use in these trucks when they were designed was probably early 90's at the latest, I think whatever learning they do is limited to a couple of values such as fuel trim.

 

Do you happen to know what the ScanGauge can give you that information as far as the readiness

 

Toyota FSM snap test recommends snap throttle open rapidly while engine is running. ECU forgets what it was doing, wonders what the hell is going on and starts paying attention. Learning DONE. If I close my eyes and picture things in my head I fall asleep.

 

Not sure, but I was referencing kinda the image that jbrandt posted how it shows when all the parameters have been met for OBD2 readiness. Oh that's right scan Guage and ultra Guage have their own display screens. Not sure man

 

Lol

 

I'm not aware of a scan gauge engine readiness test. OBDII Ready test shows when all cycles have run. I force ready test while driving, takes 5 min. But I don't clear codes beforehand.

 

No sh*t? Interesting....

 

Once you've set all the monitors it has had enough time to learn. Usually the idle relearn takes the longest but the only other learning is long term fuel trims which is just an average of how you usually drive, speeds and loads.... So if you've driven your usual variety then it's probably learned what it's gonna learn

 

A month ago maybe less my fuel trim that were usually are -+5 sometimes up to 9 Max, they changed to +25 +30,

After doing a smoke test and replacing all the vacuum lines and a fuel pressure test with no answers I decided to replace the fuel pump that had 300k and get an dealership OEM MAF.

THe results after the fuel pump and new MAF were perfect with fuel trims 0 to +3 or 4,
I DID also reset the ECU by disconnecting the battery overnight after the fuel pump.

A few days later and 300 miles the truck still dose not have any where as much power then it had before and the AFR at high rpms with the methonal spraying is very rich at 10. If the methis not spraying the AFR is good.
I can change out the nozzle to a smaller nozzle size to compensate for the difference in AFR and get it to 12.

So this evening I put my old MAF back in and the truck runs completely different as in excellent.

Has full power with AFR at 12.5 where it should be at full boost with the methonal spraying.

BUT the fuel trims are at +10 to +15 when full acceleration.
Idle is zero.

All this is from just changing out a new MAF for the old one with two very different results.
And the better overall performancepower wise MAF by far, is showing long terms at 10-15.

What’s up with this?

Do I run the new MAF with perfect trims With obvious less power
OR
the MAF with high trims that makes much more power over the rpm range

 

Wow. That's a tough one. But I guess if I was in your shoes I'd run the MAF that gives l you the correct numbers. And obviously you'll be keeping an eye on it.