Run a tank of E85 orleave well enough alone ?

[belair62]

2011 5.3 flex hasn't run E85 in a couple years. Was thinking of throwing a half tank in as a cleaning agent. Truck runs perfect now. Should I throw the dice or leave it the hell alone ?

 

[opfor2]

I was wondering about doing the same thing.

 

[Marky Dissod]

I've only ever used E85 under the following conditions:
1. It's at least 25% cheaper than E10 or 30% cheaper than pure gasoline
2. ALL the E85 was absolutely gonna get used up that same day
3. also use a bottle of Chevron w/ TechRon in the same tank
4. No more than half a tank of E85 at most (13 gallons for Tahoes)

Don't like storing E85 in my gastank for more than a day, it'll pull moisture from air and then push it through the fuel pump.
If E85 isn't cheap enough, it's not worth the MpG sacrifice

 

[mikez71]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

 

[Charlie207]

Do you notice any bump in power?

 

[Marky Dissod]

I've no problem with using E85 if it's cheap enough, only with NOT using it up quickly.
And it's almost never an arid day in NYC ...

 

[j91z28d1]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

I mean it would absorb water if left in a open bucket. but a sealed fuel tank in a truck that's listed as flex fuel. not something I'd worry about and even if it did suck up water, as long as we can trust gm to use ethanol safe fuel system parts in their flex vehicles, it wouldn't add any corrosion and water would just be water injection. which also cleans carbon really well. we used to decarbon old Ford straight 6 engine by blocking off the radiator till they get about 260, Rev them up and pour water down the carb. took about a gallon or so and like magic, clean tops of pistons. rebuild the carb that caused the carbon knock on the first place and send it on its way. engine would outlast the equipment.

I used to run some e85 thru my no flex car every once on a while to clean it up, then I'd follow the don't go 100% and try to use it the same day or so. but without any tuning don't run in PE mode. which is above like 70% throttle on most cars. the high octane is pretty forgiving even if you run it a bit lean thou. that car ran flawless for over 100k of pure abuse till it got stolen in Nola. and even a year or so later when it was recovered it still sounded perfect. sadly they wouldn't let me buy it back for the drivetrain.

my yukon is a non flex and I keep meaning to grab some e85 to clean up some carbon I saw with a bore scope while doing plugs. wasn't bad, but couldn't hurt, just haven't yet.

 

[j91z28d1]

wow did not know it would pull moisture so fast.

FWIW I put in a couple full tanks lately and it runs as good as ever, although i only get 8mpg (all city, get 11.5 normally)

if you had access to the e85 timing tables to add a few deg and clean up the fueling a bit. it would probably almost match what you get on say 87.

I've got friends deep into the e85 stuff in German cars and with a little bit of clean up they get same or better mileage from e. but their factory ecm's also run full wideband closed loop control and direct injection. they ran crazy numbers that don't make sense in my ls based world haha.

 

[Marky Dissod]

Do you notice any bump in power?

Tough to measure the extra power.
Quicker throttle response is definitely obvious, but since traffic has been made worse with all the extra bike lanes, there's almost never enough room to enjoy it.

 

[belair62]

Thanks all. I just read where this virtual ethanol sensing gets screwed up and then boom it runs like crap on regular gas and you need a scan tool to correct it. I feel like there is always a bomb waiting to go off on this thing.