REX Unit Fuel Capacity

[Milam]

I have a 2017 i3 REX.

Just for the fun of it.
I ran my REX unit out of fuel.

It took 2.313 gallons to fill it up.
Is this the capacity of the tank?

Thanks

 

[cancad]

Where are you? What is the range displayed when the tank is full?

I am in Canada and was told we have American version, in which the tank is limited to 1.9 gal. I am trying to figure it out but don't know how.

 

[jadnashuanh]

Where are you? What is the range displayed when the tank is full?

I am in Canada and was told we have American version, in which the tank is limited to 1.9 gal. I am trying to figure it out but don't know how.

The vehicle can be coded to allow the full use of the tank. The dealer won't do it, but it's not all that hard to do yourself. You do need to buy an adapter that plugs into the OBD-II port (which one depends on the s/w you use to program the car), but they are not expensive. If you have an Apple product, the Bimmercode app can do it. If not, you'd need to download a bunch of software and work your way through configuring it and figuring out the programming. Some people offer remote programming.

 

[Milam]

I live in Oklahoma City, Oklahoma, USA

It usually indicates 68 miles, when it is cold outside..
More during the warmer months.

The fillup took 2.313 US gallons.

I am wondering, is there more available?
I do have the adapter.

Thanks

Tom

 

[alohart]

I am in Canada and was told we have American version, in which the tank is limited to 1.9 gal. I am trying to figure it out but don't know how.

2014-2016 North American i3 REx's have their fuel tank capacity software-limited to ~1.9 gal. This software limit can be eliminated by coding.

2017 North American and all other market i3 REx's allow full use of the physical fuel tank capacity, so no coding is needed to be able to use the full fuel tank capacity.

 

[jadnashuanh]

IOW, the tanks installed are identical...it's just that the software is changed to indicate when the car indicates it's empty and thus how much range you might get from it. Unless you ran the car out of fuel, 2.3x is pretty close to the 2.4. If the pad where you filled up was not perfectly level, that can affect how much you can put in the tank, too.

 

[cancad]

2014-2016 North American i3 REx's have their fuel tank capacity software-limited to ~1.9 gal. This software limit can be eliminated by coding.

2017 North American and all other market i3 REx's allow full use of the physical fuel tank capacity, so no coding is needed to be able to use the full fuel tank capacity.

This makes a lot of sense because for MY 2017 and later the battery capacity has been increased so that even with 2.4 gal the fuel range will not exceed the electric range. Full use of 2.4 gal tank is what I thought it would be.

Mine is a new 2018 Rex. I have ordered Vgate iCar Pro (thanks to Jim's advise above) and will confirm the info once I get it.

 

[cancad]

Today I had a chance to code my 2018 i3. Under “Increase fuel capacity” the original parameter was “unknown value”. I hit “active” and then “code”. After coding completed the fuel bar on the cluster has no change. In the app “unknown value” is gone, and “active” is the only option. These may all mean the fuel tank was always in its full capacity.

 

[alohart]

Today I had a chance to code my 2018 i3. Under “Increase fuel capacity” the original parameter was “unknown value”. I hit “active” and then “code”. After coding completed the fuel bar on the cluster has no change. In the app “unknown value” is gone, and “active” is the only option. These may all mean the fuel tank was always in its full capacity.

Starting with 2017 models, no REx models anywhere in the world had software-limited fuel capacity. So there was no possibility for you to increase your i3’s fuel capacity via coding.

 

[jadnashuanh]

While BMW fought it, to get the credits it wanted from CA, they imposed a rule that the engine assisted range could not be more than the battery range...so, with the original sized battery pack, they had to program the car to function as if it were out of fuel at a lower value than reality (rather than actually putting in a different tank and sensor). Once the battery pack enabled longer battery range starting in 2017, that restriction was no longer required, and they enabled the full use of the tank.

 

[Srivenkat]

Does running out of fuel on the ReX mean there's not any left in the tank or does the tank still have a limited amount of fuel to keep the fuel pump and such lubricated. The reason I am asking is, is it possible to run the tank dry so gasoline doesn't gel out of non-use, but only put gas in the tank when one intends to use the ReX?

 

[Srivenkat]

I see my question is already answered in https://www.mybmwi3.com/forum/viewtopic.php?t=5206
Thanks.

 

[jadnashuanh]

For BMW specifically, and most fuel injected engines generically, it's not a good idea to actually run the tank dry. That doesn't mean that there's not some fuel left...the sensors and computer can make it look and act like it's all gone. Many fuel pump designs rely on the liquid running through them to both lubricate and cool their operation, so running it dry is problematic. It could also be tough to refill the injection lines, and the injectors may not like to be dry, either. The bottom of the tank is also where any crud may accumulate, so even with the filters, it's not great to disturb what may be accumulated there.

 

[AndrewDebbie]

If you have an Apple product, the Bimmercode app can do it. If

Bimmercode works with Android too now. Many of the compatible of the OBD dongles are still Apple or Android only though.



https://www.bimmercode.app/adapters/

 

[AndrewDebbie]

The REx tank is 9.0 litres to fill from empty indicated. That is about 2.377 US gallons or 1.98 Imperial.