Retrofitting/fixing EU gas tank into US model?

[busaman]

ive just had a good look at the PDF as i see it there are two easy ways that shouldn't trigger any faults. 1 increase the size of the base of the tank (if there is room) that wont interfere with any sensors just give more volume (there is very little pressure in there anyway).
2 have a reservoir built into the filler neck pipework also shouldn't interfere with the electronics.

It's not the physical interference that matters. It's the amount of air and it's pressure changes when the temperature changes. Any volume of air that you'll add to the tank will throw off pressure changes in correlation to temperature changes, and that's what the system is monitoring.

im not sure the system will monitor it that closely i will study further, i can confirm the US and UK tanks use the same part number therefore are the same also they cost £383+vat

 

[Tomasz]

im not sure the system will monitor it that closely i will study further, i can confirm the US and UK tanks use the same part number therefore are the same also they cost £383+vat

Here, from BMW's own manual:

7.6. Tank leak diagnosis
After the shutdown phase of the vehicle (terminal 15 OFF) a test of the tank leak diagnosis is initiated by the hybrid pressure refueling electronic control unit TFE control unit. This is carried out over a period of approx. 6 hours. In this period the temperature and the pressure in the stainless steel tank are measured. As the pressure changes depending on the temperature, it is possible to identify a pressure loss in the fuel tank using a stored characteristic curve in the control unit. A prerequisite is therefore that the temperature changes over the test period. If this does not happen no results can be concluded.
The ambient air pressure is also included in the calculation of the characteristic curve. An internal sensor in the RDME control unit determines this value and makes this information available to the hybrid pressure refueling electronic control unit via the PT-CAN.
If during the test phase the vehicle is started no result can be evaluated. Each time after the shutdown phase of the vehicle the tank leak diagnosis restarts via the TFE control unit.
Following a comparison of the measured pressure readings with the saved characteristic curve in the control unit, information is transmitted to the RDME via the PT-CAN in the case of a deviation from the hybrid pressure refueling electronic control unit. A corresponding entry is set in the control unit. This happens as soon as the ignition of the vehicle is switched on.

To me it means 'yes, we monitor it _that_ closely'. And that also means that every significant change in tank's volume will throw that algorithm off and illuminate 'you've got leak' note.

 

[busaman]

wow what an overkill and so pointless, most people would notice a leak or smell it.

 

[jadnashuanh]

wow what an overkill and so pointless, most people would notice a leak or smell it.

Most of this is software, and once it is done, the unit cost is essentially nil, and, since you're dealing with high voltage and the potential for a spark (not likely, but possible), it would be nice to not blow up the car especially if you happen to be in it! WIth such a small volume tank, and many people will park it outside, I'm not sure you'd really notice a small leak. PLus, to get the fuel reliably to the motor, the tank is pressurized while driving, too, and blowing raw vapors into the air doesn't get you any emissions credits! Most enthusiasts would notice and investigate a fuel smell, not true for everyone. One gallon of gasoline has about the same energy as 8 sticks of dynamite. Course, it's hard to blow up liquid gasoline!

 

[rtanov]

Someone from the FB group just figured out how to unlock the 1/2 gallon reserve in a US car. He posted a 2.465 gallon fill up receipt. Not quite clear yet but it seems to be through coding only. If so this is great news.

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery!

 

[Tomasz]

Someone from the FB group just figured out how to unlock the 1/2 gallon reserve in a US car. He posted a 2.465 gallon fill up receipt. Not quite clear yet but it seems to be through coding only. If so this is great news.

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery!

Yes, I've been known to get to the bottom of every problem I point my sight on.

http://tomasz.korwel.net/2015/01/16/favorite-i3-coding-change-9-l-2-4-us-gal-fuel-tank/

 

[rtanov]

Someone from the FB group just figured out how to unlock the 1/2 gallon reserve in a US car. He posted a 2.465 gallon fill up receipt. Not quite clear yet but it seems to be through coding only. If so this is great news.

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery!

Yes, I've been known to get to the bottom of every problem I point my sight on.

http://tomasz.korwel.net/2015/01/16/favorite-i3-coding-change-9-l-2-4-us-gal-fuel-tank/

So impressed! Congratulations for figuring it out!

 

[GodFollower]

Called it

Good work on finding the coding variables!

 

[mindmachine]

Someone from the FB group just figured out how to unlock the 1/2 gallon reserve in a US car. He posted a 2.465 gallon fill up receipt. Not quite clear yet but it seems to be through coding only. If so this is great news.

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery!

Yes, I've been known to get to the bottom of every problem I point my sight on.

http://tomasz.korwel.net/2015/01/16/favorite-i3-coding-change-9-l-2-4-us-gal-fuel-tank/

Absolutely awesome piece of engineering. Who would have ever thought the tank size would be software limited.

 

[Pixelpro]

Someone from the FB group just figured out how to unlock the 1/2 gallon reserve in a US car. He posted a 2.465 gallon fill up receipt. Not quite clear yet but it seems to be through coding only. If so this is great news.

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery!

Yes, I've been known to get to the bottom of every problem I point my sight on.

http://tomasz.korwel.net/2015/01/16/favorite-i3-coding-change-9-l-2-4-us-gal-fuel-tank/

Absolutely awesome piece of engineering. Who would have ever thought the tank size would be software limited.

So how does the average person go about making this software change?

 

[mindmachine]

Edit: Oh, I just realized that the OP is Tomasz and the person who discovered this and posted on FB is named Tomasz. OP: congratulations, great discovery![/quote]
Yes, I've been known to get to the bottom of every problem I point my sight on.

http://tomasz.korwel.net/2015/01/16/favorite-i3-coding-change-9-l-2-4-us-gal-fuel-tank/[/quote]


Absolutely awesome piece of engineering. Who would have ever thought the tank size would be software limited.[/quote]

So how does the average person go about making this software change?[/quote]

If you aren't opposed to using facebook, there is a BMW i3 group there, just search coding and all the info you need is available for download there are even links to download the software you will need for free.

You can also search coding here on this forum, but the facebook group is the better place for getting all the files ect....

 

[i3an]

WARNING! European REX drivers should NOT click over to Tomasz' link, as the sight of his gas/petrol receipt might trigger nausea — the price/gallon looks like it has the decimal point in the wrong place.

 

[Neil]

Fantastic detective work!

Does anyone know if this coding gets blown away never to be recoded again once the new software is installed with the improved KLE?

 

[Jeffj]

I have the new KLE and software, and I'm still able to code my car using the files/guidance provided in the referenced Facebook group. I haven't coded Tomasz's fix in, but I don't see why it wouldn't work with the new software. I'm pretty sure Tomasz has the new software, btw, from other posts he's made.

And yes, every time there is a software update from BMW, the coding changes that you've made will most likely be blown away. Just means you have to be prepared to re-code after an update.

 

[websterize]

Maybe the reserve BMW incorporated is not a physical reserve, but a software modification to shut off the REx a bit sooner than the UK counterparts?

An outstanding assist for Tomasz's goal, GodFollower — always enjoy reading your insights about the i01.

 

[Tomasz]

WARNING! European REX drivers should NOT click over to Tomasz' link, as the sight of his gas/petrol receipt might trigger nausea — the price/gallon looks like it has the decimal point in the wrong place.

And it's not the cheapest fuel I've purchased recently. I have receipts going as low as $1.759/gal from within last 3 weeks. Makes me second guessing my choice to upgrade my 31MPG ICE to i3 :-(

 

[Blue20]

Anyone how those two parameters work?

I guess the ohm is for the gauge. How does the other value create extra space for gasoline? It deactivate a balloon block?

 

[I33t]

I think it declares the tank empty before it actually is and stops the REX.

 

[Tomasz]

I think it declares the tank empty before it actually is and stops the REX.

Exactly. When the BMW fills out the tank for the first time, they put some amount, e.g. 1 gal but it records on the computer as 0.5 less (0.5 in this case). then whenever it goes down to zero the computer thinks it's 0 and shuts down the engine.

As I've said before - this is very smart way of operating. Since the 0 level is based on sensor reading it can be adjusted when they change vendors or (like here) decide to limit amount of fuel available to you. Shutting down the engine before the tank is empty is also great way to prevent air from getting into the lines (did any of you try to start diesel engine starved for gas in 10-15 y.o. cars?) and it also prevent premature wear of the fuel pump (fuel lubricates it).

As a matter of fact I'm quite sure that there is at least another 1l (0.25 gal) available below zero even in european models for those very same reasons.

 

[busaman]

ok going back a few posts @tomasz have you seen what they do in the coding for tank pressure/temp monitoring.