vwsb1974
Posts: 4
Joined: Fri Feb 22, 2019 6:37 am

Time between fill ups

Mon Aug 19, 2019 7:55 am

So i have had my I3 since last September and I am just wondering how log between fill up's is to long? I last got gas on the 24th of February It was 93 non ethanol. I know the I3 has a pressurized fuel tank to help keep the fuel fresh. I have a little over 5,500 mils since i got that tank and have used the REX twice on this tank and the car has performed one maint. cycle due to the REX not being used. The car has also recently been in for its annual service / oil change. I have coded the car for the larger tank size and it is still showing over half a tank. I am just wondering if anyone else has gone this long between fill ups and if so have they seen any adverse effects from stale fuel.

User avatar
MKH
Gold Member
Posts: 523
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: Time between fill ups

Mon Aug 19, 2019 1:22 pm

Condensation/moisture in the gas - which is the biggest problem as gas sits in a tank, is supposed to be prevented by the pressurization. Since I rarely use my Rex engine, and only get the maintenance cycle runs, I add PRI-G small engine fuel stabilizer, to be on the safe side. Military uses the PRI-G stabilizer in stored fuel that will sit for years.
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

jadnashuanh
Posts: 4788
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Time between fill ups

Tue Aug 20, 2019 2:14 pm

Personally, I'd probably run that gas out and replace it. My personal thought is that, one, I'd like the oil to be circulated through my engine more often that once every 6-weeks or so to minimize start up wear (one study concluded that 90% of engine wear occurs in the first 30-seconds of cold starting that can get worse if not run and all of the oil coating runs off), and any moisture that might have condensed in there can start to corrode things, and two, just to be on the safe side, put fresh fuel in there won't hurt. Older engines with carburetors were maybe more subject to gumming up, but fuel injectors are harder to clean if they do. Lucky you can buy gasoline without ethanol in it...can't really find it around here easily.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV

vwsb1974
Posts: 4
Joined: Fri Feb 22, 2019 6:37 am

Re: Time between fill ups

Tue Sep 03, 2019 8:28 am

I have since started using this tank of gas. I think moving forward I will use the REX at least once a moth or so just to keep the oil film on the cylinder walls. I wonder if the computer is programmed to stop the REX when both valves are closed to prevent condensation from entering the engine when prolonged times of no use?

joni3s
Posts: 47
Joined: Wed Oct 02, 2019 11:16 am
Location: VA

Re: Time between fill ups

Wed Oct 09, 2019 11:06 am

I've started to use REX HSOC @40-50% once a week or so , when I know that the most local DC Fast Charger is more expensive than using the REX for 25 -40 miles. Thats about 1/4 -1/3 of the tank.

I drive about 75 miles weekdays HOV highway round-trip on a 94Ah, but don't have a home 220v charger yet, soon I hope, so my use is a mix of DC Fast , 110V (usually 7 hrs a day so 20 miles range) and level 2 once in while (usually not worth the effort to find one, unless it's where I am at).
2018 I3s rex

alohart
Posts: 1920
Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Time between fill ups

Wed Oct 09, 2019 6:15 pm

vwsb1974 wrote:
Tue Sep 03, 2019 8:28 am
I wonder if the computer is programmed to stop the REX when both valves are closed to prevent condensation from entering the engine when prolonged times of no use?
I'm guessing that there's no engine state in which all valves in both cylinders are closed.
Aloha,
Art

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

Return to “BMW i3 Rex Specific Discussions”