2017 max tank fill question.

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Miyanc

Member
Joined
Dec 12, 2023
Messages
18
Location
Waxhaw, nc
I have a 2017 94 rex. When I attempted to run down the gas tank ( just didn't know how old it was) . I then added some gas treatment and refilled but was only able to add 1.8 gallons and I ran the tank down to 2 miles left. So when I went into the bimmercode app I thought it was telling me my year vehicle was already enabled (to max capacity). I assumed that meant the 2014-2016 had the tank max modified and 2017 and newer was not.

Am I still facing the phony max or is it a guess o meter fail safe or something else?
 
Your i3's fuel tank did not have its capacity artificially limited by software as did 2014-2016 i3's. Never having owned a REx, I can't explain why only 1.8 gallons filled your tank. Maybe that's normal without risking overfilling and flowing gasoline into the charcoal filter.
 
That was my thinking as well, I was hoping someone with rex would comment. I also could have posted in the rex only threads.
 
I got a 2019 Rex and a 2018 Rex, they both have 2.1x gallons in the tanks once you unlocked it changing the settings...
 
I got a 2019 Rex and a 2018 Rex, they both have 2.1x gallons in the tanks once you unlocked it changing the settings...
See so this is where I am confused. First I thought it was 2.4 gallons and I thought only the 14-16 were limited?

I assume the tanks are the same 14 and out. I may be wrong. I could run out the gas engine. I stopped at 2miles or something, that may account for the .3. if I added 1.8. and maybe it is 2.4 and I know not to try and over fill, never have on any vehicles.

In Feb I am taking my rex on 400 mile plus each way trip. I am planning just 1 main charge and 1 top off before arrival. I plan to use the rex hsoc and to supplement conditions. Meaning I should be able to do this ( first leg is 150 miles, second 150 and 50, leaving at 100 I won't need a long charge for the last 50) except for heating and speed. I will not be driving 56 in the cold ( side note to those that say they just use the seat heaters, do you breathe at all?). So if I drain to fast I will top off the gas and keep driving. I will also carry a 2 gallon can in the frunk. I am hoping the hotel has something or maybe DC near by. It's a school trip to DC so I don't have the hotel info yet.
 
You're measuring volume in gallons so I assume you're located in the US. But if my assumption isn't valid, there are some other things to consider. One thing is that different countries have different trade regulations regarding selling gas on gross (actual measured volume) or net (temperature compensated volume). In the US, gas is sold by gross volume, so that shouldn't be the issue you're seeing. Also, US Customary and Imperial gallons are substantially different. I don't know if gas is sold by the Imperial gallon anwhere now, but it was a source of confusion with my Home Assistant BMW Connected Drive plugin before the Home Assistant dev team was made aware of the differences between Imperial and US units.

Also, also, is this repeatable at different filling stations? Station owners can set the backpressure spitback preventer to be more or less sensitive and therefore stop filling sooner or later than other places. ICE drivers with 10-20 gallon tanks probably wouldn't notice a quarter gallon difference in ullage from one station to another, but that's an eighth of a tank on an i3!
 
I have taken my Rex on several 1000+ mile trips, all in a single go. You need to have the car recoded with the range extension set to be able to activate at 75% and the fuel tank set to accept 2.4 gallons. At empty i will get 2.42 gallons in but it will come up to the cap and I try not to do that. I have, at other times, overflowed. So when Empty I just put in 2.25 and I am off and running.
I have also found that driving 65 miles an hour on a long journey will maintain my battery and anything over 70 will slowly decrease battery percentage.
65 also runs a lot less fuel. I can go almost 2 hours at 65 or an hour and ten-twenty minutes at 75. So at the end of the day, 65 equates to fewer stops, and the same arrival time. If i Get behind a lorry and (if you have Driving Pro Adaptive CC enabled) you can get 2.25 hours on a tank of fuel.
Before I had my i4 I would road trip my Rex quite often between southern California and Eugene, Oregon, which is about two-thirds into the state - or 960 miles. you get used to going slow. It is also less stressful.
My i4 makes the same trip with 3 stops to charge and at 75 miles an hour.
Also, forgot to mention, I only use Eco Pro mode - in both cars. It does not effect range in the i4 but it sure does in the i3.

*I took our 2019 Rex from So Cal to Coeur D'Alene, ID in a single go once. (about 1800 miles due to the route I had to use). There was a fire that made me re-route . It did just fine.

Hope all of this helps
 
See so this is where I am confused. First I thought it was 2.4 gallons and I thought only the 14-16 were limited?
That's my understanding as well. With 2017+ no coding needed. Full use of gas and HSOC can be triggered at 75%
I will also carry a 2 gallon can in the frunk. I am hoping the hotel has something or maybe DC near by. It's a school trip to DC so I don't have the hotel info yet.
I'd think twice about that. There are two schools of thought: (1) it's not a problem; (2) the frunk is a crush zone for impact to protect the passenger compartment and you don't want something volatile in that area.

If you can see the gas station at the top of the highway exit (on your side of the highway), it takes about three minutes from exit ramp to entrance ramp with 2.4 gallons added.

For your trip to DC, nothing says that you have to deplete both gas/battery before stopping. You could make a quickie gas stop when the fuel is empty and state of charge is still 75%. That would add an extra 66 gas miles to your range. If you use this strategy, its good to stop before the state of charge goes too much under 75% because when you re-start the car, you can only HSOC for the current amount in the battery.

Seems like you could do the DC trip with one charge stop, not two. The battery stops are a real time suck, not only from chargers not working (out of service), but sometimes waiting for a charger to become available when you find a working one.

Also, despite HSOC, the battery will still deplete over about 65MPH, more so with heat. It's more than the REX can put out.

Finally, I wouldn't count on the hotel -- even having a charger doesn't mean an open charger. There are many fast chargers around DC, so you should be fine.
 
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"The fuel tank capacity is 9 liters / 2.38 gallons with a 2 liter / .5 gallon fuel reserve." -pg. 41, W20 Engine Technical Training, ST1403a, 2/12/2014 ed.

Assuming USG, the way I read that, 2.38 gallons is the total volume of the tank and 2.38-0.5 = 1.88 (1.9) gallons available. I do not believe coding allows running the tank dry, so the maximum additional usable capacity is simply not 2.4. People might be overfilling to stuff 2.4 in, but the vapor canister error is in their future if done on a regular basis.

As suggested, perhaps the LCI simply has a larger tank, but this discrepancy has existed since before the LCI was introduced, so I think a lot of people just aren't paying attention to the amount going in, or they are overriding automatic pump shutoff.

2.1g +/- a tenth or so is all I have ever gotten mine to take without overriding the pump shutoff, so coding really only added 0.2g of usable capacity, and that clearly jives with the tech specs.
 
I think for this trip and maybe just the way up, I will carry the gas can. There is a stretch from Raleigh to Richmond that not has many lengthy gaps, but even if you get off an exit to get gas, the station can be far. This being my first real attempt at road tripping and I am not sure the variables I will be ok with. So far my windows fog pretty quickly. So opening a windows or running HVAC or traveling above 65 (which I doubt) makes me less comfortable running dry. I have pushed the tank and battery to low and recharged, but it was back and forth in town. I don't know the limits of the car. So in my brain, until I know better, I will probable overcompensate. Meaning make more stops then needed to be sure. I would rather try to push it and rely on the 2 gal in the frunk if my plans fall thru. I have the trip broken down to 2 160 miles stops. The gom says I can mostly do 200. The stops I picked are 12 plus ccs chargers and in the parking lot of a gas station. So if I get there and the chargers are broken or full. I can pump gas and go. Maybe needing to refill gas a few times.

The reason for only the way up, I will be racing my daughter's school bus. I am going to try and leave before them, but would like to try and get to the hotel before them. They will also be stopping at some point for food and bathrooms.
 
"The fuel tank capacity is 9 liters / 2.38 gallons with a 2 liter / .5 gallon fuel reserve." -pg. 41, W20 Engine Technical Training, ST1403a, 2/12/2014 ed.

Assuming USG, the way I read that, 2.38 gallons is the total volume of the tank and 2.38-0.5 = 1.88 (1.9) gallons available. I do not believe coding allows running the tank dry, so the maximum additional usable capacity is simply not 2.4. People might be overfilling to stuff 2.4 in, but the vapor canister error is in their future if done on a regular basis.

As suggested, perhaps the LCI simply has a larger tank, but this discrepancy has existed since before the LCI was introduced, so I think a lot of people just aren't paying attention to the amount going in, or they are overriding automatic pump shutoff.

2.1g +/- a tenth or so is all I have ever gotten mine to take without overriding the pump shutoff, so coding really only added 0.2g of usable capacity, and that clearly jives with the tech specs.
 

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No get the Wavian 10L instead. Ir fits perfectly in the frunk. It holds 2.6 gal. Just fill it to 2.1 gallons so that you can dump it in when you need to.

https://www.amazon.com/Wavian-USA-J...mzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc
I saw that one and it was my second choice. It's top of the line. But my frunk is filled, so on trips I carry the can in the back. The Wavian, with its narrow bottom would tip over unless I strapped it in. That's why I bought the round bottom Justrite.
 
So I filled the first time. Range ended at 2 miles and got 1.8 into it. I had added fuel cleaner. My 2 reasons were because I didn't know how it all worked in practice and second, I wasn't sure how old the gas was. So I just ran it down again, mostly to check capacity. This time I ran it down to 2, but the difference is I parked it and then went to restart and drive out and at first couldn't understand why hsoc wouldn't engage. Then realized that while parked the gom decided I was done. So I then stopped at a gas station and specifically choose 1 that is on a slight decline. So fill port was slightly higher and it got 2.21 gal. So I think, like the gom, I am within the norm of variability.
I will carry, probably gas station convenience store quality can, if I take anything on this trip. I only need it to get thru the first 320 miles. Leaving full, 1 full charge and gas refill gets me to Richmond. This leaves me with many options depending on capacity at that time. It's only 80 or so miles to the hotel (I am guessing). My plan will be to use the can to refill in Richmond while at a DC charger. The gas plus whatever I get while charging. For the trip home I can take my time, I even plan on maybe getting a hotel on the way.
 
I recently took a trip that was all planned out and the biggest hiccup I had was where they showed said chargers along my trip. Now when I plan, I plan in some pucker factor. When I showed up to one charger. It didn't work at all. The next one showed that it was in the middle of a residential area (not there) and yet another had me at what might have been a very large business complex with a multi-level parking garage and industrial buildings. Never found it. No signs directing you to it. Its was one hell of a way to get over my pucker factor on my very first long distant trip.
 
I recently took a trip that was all planned out and the biggest hiccup I had was where they showed said chargers along my trip. Now when I plan, I plan in some pucker factor. When I showed up to one charger. It didn't work at all. The next one showed that it was in the middle of a residential area (not there) and yet another had me at what might have been a very large business complex with a multi-level parking garage and industrial buildings. Never found it. No signs directing you to it. Its was one hell of a way to get over my pucker factor on my very first long distant trip.
Finding charging takes a little planning. Plugshare is a good app to help find charging sites. Waze also has a function where you can specify your vehicle is electric and the charge plugs it takes. It will find charging points along your route.
 
I recently took a trip that was all planned out and the biggest hiccup I had was where they showed said chargers along my trip. Now when I plan, I plan in some pucker factor. When I showed up to one charger. It didn't work at all. The next one showed that it was in the middle of a residential area (not there) and yet another had me at what might have been a very large business complex with a multi-level parking garage and industrial buildings. Never found it. No signs directing you to it. Its was one hell of a way to get over my pucker factor on my very first long distant trip.
It's very regional specific. Sadly it's not as it should and not as Tesla is, and not that they are perfect but charging network is light-years ahead of OTHER.

I have 7 apps downloaded and set up with payment options and that doesn't include the car. Even planning apps like "A Better Route Planner" leave much to be desired. They all seem promising and in theory should do great, but I mostly find holes in each 1. So I use all of them to plan and double check and Google maps to verify routes. My plan b is called Rex. This was the only other option for us as a first EV, other then Tesla which we couldn't afford. Now if it was only a 2014-16 bev or a leaf or limited range car we would have been fine for a commuter. But having the Rex means if I can't find or don't like the looks of an area, I can gas it up and go.
 
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