MIU G3 - Battery removal and memory loss

[JulienFlry]

Hello Guys,

I just finished the MIU G3 injection V750 pdf (link below, interesting for the one who want to learn)
https://www.guzzitek.org/documents/injection/ECU_MIU-G3_Training.pdf

When i first purchased the V7, the previous owner didn't ride it much, almost not at all, disconnected the battery and charged it before to sell it to me.
Then I came to purchase the bike and the idle was not stable plus the bike had difficulties to start.

I changed the battery, the sparkplugs, did the valve clearance and it has seemed to me that the more I drove the better it felt.
I've assumed until now that the new battery spark plugs and valve clearance did the job, and I didn't worry about that since now it rides and start nicely.

Now that I am reading about the self-learning feature of the ECU and the correction that it brings to the 2 matrices (cold and hot engine), is it possible or even just correct to imagine,  that maybe when the previous owner disconnected the battery it cancelled the memory of those corrections and that the bike needed few rides and start to improve the idle and the start ?

I will soon buy a map from Beetle so I am not trying to understand how to improve it, but more to understand how my guzzi works.
Also how disconnecting the battery affect the ECU, does it for example reset so autolearning of the TPS ?

Cheers,

[DoubleGuzzi]

Connect a "smart" charger: problem solved.

[Kev m]

The auto-adaptive learning is common across all feedback type injection systems I've ever seen. It's often referred to as "fuel trim" or something similar in the automotive world. It basically means that the ECU uses oxygen sensor feedback to add a correction factor to the OEM maps to better dial them in to actual engine operation.

As the tech material mentions this can account for things like a dirty air cleaner or specific valve adjustment. It's a slowly built and constantly modified correction factor. And though it is recommended that it be manually reset after performing service, the ECU will eventually adjust it to the new conditions if that's not manually reset.

I'm not sure whether or not disconnecting the battery resets it, but it wouldn't surprise me.

And either way that likely has something to do with some of what you felt after performing maintenance on it.

But generally the changes should be small and I would think often go unnoticed.

I believe the TPS is automatically relearned by the ECU but you can also force it to occur with a scan tool.

Should you run a Beetle map in the future it will most likely disable and ignore the oxygen sensor feedback essentially rendering all fuel trim adaptive learning functions null. But the Beetle map should have a far greater impact than any adaptive learning anyway.

Me, I'm still running OEM maps because they have proven to be fine for my purposes.

[Tom H]

To start with, if you don't have Guzzidiag (Free), cables, and a tablet, or laptop or computer to connect to the bike get one. I would suggest a Windoze based device over Apple or Linux.

I am not sure if removing the battery will cause the ECU to lose it memory. It may?? Not all, but maybe some.

With Guzzidiag you can do a TPS reset and auto learn reset. I think that auto learn takes a bit to learn how you ride.

If your going to get a new map, then Guzzidiag and the upload and download software is needed as well as the correct cables and a PC of some sort.

Tom

[JulienFlry]

Thank you Kev m this is very interesting to learn for me coming from a carbureted world :)

I didn't feel this way after performing the maintenance but when I purchased the bike.
So if I understand what you are saying is that either way, the correction made by the ECU is so small that it doesn't really make a big difference?

About the map i've read that the Beetle map ignore the O2 data but I never read that they ignore the intake manifold pressure data and it seems this pressure play an important role in the fuel trim especially for cold start when 02 data is not available isn't it ?


Tom thank you, yes indeed. I ordered this cable from lonetec or something like that and I am in the process of reading the old post about the guzzidiag and the new tutorial, very interesting I am learning so much. But again for now I am not in the process of improving anything but more trying to learn as much as I can about the V7 :)

That would be interesting to know if disconnecting the battery could actually start a learn reset.

Thank you :)

[Dirk_S]

When I wanted a fresh start with my stock mapping, I always disconnected the negative / ground line for around 15 minutes. I believe I’ve read this in multiple forum responses, and it feels to me to actually do the job, but I can’t recall if it’s actually in the literature of any of the manuals.

[Bulldog9]

When I wanted a fresh start with my stock mapping, I always disconnected the negative / ground line for around 15 minutes. I believe I’ve read this in multiple forum responses, and it feels to me to actually do the job, but I can’t recall if it’s actually in the literature of any of the manuals.

Before reconnecting, I also touch the + and - leads together and turn the key on and click the starter button. In theory (or in my mind) this will drain all memory and latent power in the dash and ECU clearing all.  Have gotten a few deadlined bikes this way including a new V85 that got water in the grip controls after riding in the rain. Bike wouldn't even start, dash dead. THis cleared enough to get it started and ridden to a safe place to do further diagnosis. I've also used it to the Triangle of death on my CARC bikes and other running issues to reset parameters to base.

[Kev m]

Thank you Kev m this is very interesting to learn for me coming from a carbureted world :)

I didn't feel this way after performing the maintenance but when I purchased the bike.
So if I understand what you are saying is that either way, the correction made by the ECU is so small that it doesn't really make a big difference?

About the map i've read that the Beetle map ignore the O2 data but I never read that they ignore the intake manifold pressure data and it seems this pressure play an important role in the fuel trim especially for cold start when 02 data is not available isn't it ?

The map sensor has nothing to do with adaptive fuel trim. The map sensor is used for initial air/fuel ratio calculations. The type of EFI system used by this (and most, maybe all bikes) is called a Speed Density system. It uses engine rpm (speed), and air density (MAP) signals along with things like air temperature, engine temperature, and throttle position to make fueling decisions.

The fuel trim or adaptive data based on feedback from the O2 sensors is used to alter that fueling decision slightly to better dial it in. The term feedback comes from the literal fact that the oxygen sensors read how successful the combustion WAS giving the ECU an idea of how good a job it did with mapping. So the learned fuel trim is an adjustment to that standard mapping based on that "feedback".

Make sense?

[Wayne Orwig]

I'm pretty sure that most Beetle maps turn OFF the O2 sensor. Thus tossing/ignoring any learning.
Double check that with him of course.
The learning is not that important anyway IMHO.

[Kiwi_Roy]

I know for sure if you change out the battery the clocks lose their memory.
The Speedo on my V7III Special reverted to MPG from Litres per 100 Km
I still haven't got it back to how it was, its currently showing Km / Litre (about 26)
Perhaps we need a small dry cell like they plug into a car cigarette lighter socket to retain the memory while switching batteries.

[JulienFlry]

Thank you Kev m it does make a lot of sense indeed.

This part in the document got me confused :
"The G3 unit used with this engine features a self-adaptive engine management function.
This allows the ECU to adapt to the effective needs of the engine, and even compensate for engine
deteriorating factors such as, for instance, fouling of the air filter or throttle body.
To do this, the ECU uses feedback from the oxygen sensors or the MAP sensor in relation to the effective
operating conditions. In the latter instance, the effective absolute manifold pressure is used to calculate
the effective mass of air aspirated into the cylinder."

Now I understand what you say, that only the 02 sensor will "teach" the G3 unit while the engine is running based on the combustion results. Thank you again for the explanations :)
I also understand now why a faulty 02 sensor can be so problematic.

This would mean that the adaptative feature don't impact a cold start since the 02 sensor would not work.
"The MAP sensor is also used to correct the fuel/air ratio in conditions when the oxygen sensors do not
provide a signal (e.g. when the engine is cold)."

-------------
This being said, would it be correct to say that the MAP sensor has something to do with the adaptative fuel trim when the 02 sensor don't provide data eg : cold start ?
"The ECU compares the predicted pressure (vacuum) value stored in its memory against the pressure
effectively read by the MAP sensor, and compensates the injection time accordingly.
• More vacuum = less aspirated air, necessitating a reduction in injection time
• Less vacuum = more aspirated air, necessitating an increase in injection time"

If i understand this part, MAP sensor does play a role in a self-learning feature in a way that it will teach the G3 unit which vacuum to expect and adapt injection time based on this expectation.

Now the way i see it, (by the way i have mistral with stock map at the moment), when the previous owner disconnected the battery, he deleted the value stored of the predicted pressure. So the ECU had hard time at the beginning to correct the injection time especially with the after-market exhaust

Do i make any sense in my logic ?

Wayne Orwig yes I remember reading Beetle saying that all maps have 02 sensor not turned off so to say but ignored.
Thank you Dirk, that could be an easy troubleshoot trick to keep in mind :)

[Kev m]

Unless I'm missing something, what you're describing is how the EFI system always uses MAP sensor data to determine fuel needs. That's not feedback on how well the system is working, that's just the system working.

Fuel trim is how the system modifies the preprogrammed values for fuel (use this much injector dwell time for this manifold pressure, this rpm point with a cold engine etc.). The fuel trim/adaptive learning correction value modifies whatever value was in the table at that point and all points as the point constantly changes with those sensor inputs as engine load and ambient conditions vary.

I think maybe the problem is with the wording in the document. Perhaps it was written in another language and translated. It appears they are using feedback in two different ways.

* Data from sensors on ambient conditions
* Data from O2 sensors on how well the system is working


Only the latter has anything to do with how the adaptive learning works.

But the trim determined by the adaptive learning will modify what the ECU does with the first part in all conditions.

So the adaptive learning value should affect cold engine operation as well, even though the O2 sensors aren't giving live data yet.

Which brings is to another set of terms.

* Open loop operation - is when the EFI system operates off the map tables. The adaptive fuel trim is used, but there's no additional live input from the 02 sensors. Beetle maps operate this way all the time. Early EFI systems used only this state of operation. Hell Guzzi Cali 1100's were like this until the last few years of production.

* Closed loop operation - is when the O2 sensors are up to temperature and giving a reliable reading AND engine operation is steady (load, throttle etc). The ECU will lean out the mixture here for further reduced emissions. Feedback is live, it's directly and quickly affecting dwell time AND it's very very very slowly altering the fuel trim correction factor in memory for use all the time. That is to say it's slowly learning what subtle fuel trim differences work for that particular engine given it's condition.

If I haven't directly explained it well enough yet, "fuel trim" isn't the amount of fuel the map says is needed at any given moment. "Fuel trim" is the amount of variance from that point on the map based on what the ECU has slowly learned about that given motor using long term feedback from the O2 sensors.

At least this is my understanding of these systems from my years of diagnostic data. Someone with better knowledge please correct me if I've gotten anything wrong.

[JulienFlry]

Kev m you made this Chrystal clear thank you very much for taking the time.

If it's not too much to ask, one last question.

I understand that the correction is not made for a specific condition at the time but that all the points in the map are somehow connected by some algorithms therefore when one point is corrected all the map is slightly modified, is that correct?

I am asking this because the o2 sensor kicks in assuming at X degrees Celsius, that would mean that it's impossible to have a correction for all the conditions when engine temperature < X

I am guessing that the adaptative fuel trim for cold operation is only extrapolated from the feedback receive at operating temperature.

Am I correct ?

[JulienFlry]

I have found the answers to all my questions and i will continue reading about this.
thank you again guys.

"With each RPM and throttle break point intersection giving a fuel number, there are 256 individual fuel points on a map. There is something very important to remember about these 256 points.

They are all totally independent of each other. This is the true beauty of digital control systems, totally free of the dependant relationship constraints that are intrinsic to mechanical or analogue electronic systems. Just brilliant."

Source : https://www.bikeboy.org/fuelinjection.html


I've learned for the next one reading me and in the same situation as me, that the close loop and the self-adapting feature takes places only at low throttle opening and low RPM, there is not correction on the map for mid-range to high RPM and above 20% opening. Basically, when the bike operates, it does operate in an open loop. This means the ECU will adapt himself to an after-market exhaust maybe a little bit at idle and low speed but that a new map will always be the best.
 
I was confused also about the temperature and other sensors. I have also learned that the fuel trim affect only the fuel map for a given RPM/Throttle opening. (n alpha strategy) but it will not correct the other corrections maps (trim factor).

I also recommend this reading : https://www.bikeboy.org/open_closed_loop_efi.html

If anyone want to continue this conversation i would ba happy to, this is a new fascinating topic for me :)

[Kev m]

Looks like a decent source of info and probably applies more then not to our current bikes. Though it does look like it was written more than a decade ago for models that are somewhat adjacent to us so I would think there are possible differences. Still I bet it's a good source for basic understanding.

[JulienFlry]

The map sensor has nothing to do with adaptive fuel trim. The map sensor is used for initial air/fuel ratio calculations. The type of EFI system used by this (and most, maybe all bikes) is called a Speed Density system. It uses engine rpm (speed), and air density (MAP) signals along with things like air temperature, engine temperature, and throttle position to make fueling decisions.

If I understand correctly what I read from the web, the MIU G3 on the 1TB guzzi doesn’t use this air density logic but the so called alpha n strategy.
Never though this morning when I woke up that I would be able at the end of the day to make a sentence like that 😅

[Kev m]

If I understand correctly what I read from the web, the MIU G3 on the 1TB guzzi doesn’t use this air density logic but the so called alpha n strategy.
Never though this morning when I woke up that I would be able at the end of the day to make a sentence like that 😅

Good pickup on that. I made a bad assumption on that one. 

[Kiwi_Roy]

Cliff Jefferies has a good website.
Read about why he decided to build his own ECU
https://www.myecu.biz/MyECU/index.htm

Another good document
http://www.dpguzzi.com/efiman.pdf

[SIR REAL ED]

From the title of the OP, I assumed this was about taking the battery out of your bike and forgetting where you put it....

[JulienFlry]

Thank you very much Kiwi_Roy, very interesting reading indeed.
Sir Real Ed, ahaha well I hope i won't need your help for this kind of problem for at least few decades :)