E-85 Fiasco with 2010 Buick Lucerne

Joined
Aug 3, 2020
Messages
94
I own a 2010 buick lucerne with 81000 miles. It can run E85 so I decided over the past couple months to run it exclusively on that. As fate would have it. I didnt drive the car for a couple days and when I went to start it, it idled like every bolt was coming loose and then just shuts off after 5 seconds. After 4 attempts I let it sit for an hour then tried again and it fired up, still idling like an old dump truck and then smoothed out and is running fine but with a check engine light related to engine running lean. Im draining the tank and going back to regular gas. But any idea why a car designed for e85 we would do that? The only thought I had is god only knows how old the e85 was that I got at the station as I bet its not cycled often.
 
Maybe the oxygen sensor? Flex fuel cars use a special wideband oxygen sensor to accommodate everything from E0 to E85

Sitting for a few days could've brought in moisture, so you could have water in the tank :cautious:
 
In my understanding, in flex fuel cars, it take a couple of minutes for the ECU to "understand" and adapt the mixture when changing from gas to E85 or vice versa. So it's always better, when changing the fuel completely, to do it when the car is hot and drive it for a couple of minutes. Olders cars can take more time to adjust, newer ones may be way more efficient, depending on how they identify the fuel they are running.

That being said, a flex fuel car should always start with any fuel (E85 or gas) regardless of the situation.

What was the temperature when you cold started it with E85? Ethanol is hard to start when cold, but again, flex fuel cars should have some systems to overcome this.


I live in Brazil, and you may know that we use ethanol in cars since the 80's. Flex fuel cars started in 2003, and before that we had cars that run only in gas or ethanol. We don't have E85, only E100.

I own both worlds, a neat ethanol car ( 94 Opel Kadett), and a flex fuel car (09 Honda Fit). The 94 has only 1 injector on a TBI style injection, it has a auxiliary gas tank (1L capacity) on the engine bay, that literaly squirts gas on the intake through a solenoid on cold starts. The idle is always sketchy when cold. The Fit also has the auxiliary gas tank, but with a much evolved system that has 4 injectors exclusively for the cold start with gas from the little tank. The idle in the Fit is always smooth.

Cold starts on ethanol is a challenge, but could pass unnoticed depending on how your system work and the ambient temperature. But i take my experience using E100, which should be better with E85.

You should check and understand how this "cold start system" work on your car, if it have any, years without using E85 may have left some parts of it not working properly.
 
US flex-fuel cars don't have any separate cold start fuel system, and they are designed for a maximum ethanol fraction of 85%. I guess the 15% gasoline in the E85 is a highly volatile blend to make starting easier.
 
US flex-fuel cars don't have any separate cold start fuel system, and they are designed for a maximum ethanol fraction of 85%. I guess the 15% gasoline in the E85 is a highly volatile blend to make starting easier.

Yes, that's exactly what i tought! Nowdays, our flex fuel cars don't have the separate fuel tank, they use heated fuel rails on the port fuel injection. Direct injection apparently doesn't need anything.
 
I take it this is the V6? My 2012 Chrysler van supposedly can run E85 but I would never dare. I’d run some fuel system cleaner through the next several tanks of gas personally.
 
I take it this is the V6? My 2012 Chrysler van supposedly can run E85 but I would never dare. I’d run some fuel system cleaner through the next several tanks of gas personally.
I thought about that. But in and of itself isnt e85 as good as cleaner? My fear is something broke lose and clogged something, became dislodge and could happen again. Geez...agreed. I will never run this crap again...EVER.
 
From my understanding the calculation of ethanol % can get messed up and cause all sorts of drivability issues.
 
I thought about that. But in and of itself isnt e85 as good as cleaner? My fear is something broke lose and clogged something, became dislodge and could happen again. Geez...agreed. I will never run this crap again...EVER.
No it isn't, it can actually be corrosive, not as bad as methanol but not that friendly to many of the components it comes in contact with. I see a lot of injectors that are alcohol/flex fuel rated in poor condition compared to the ones that run 10% or none.

https://www.sae.org/publications/technical-papers/content/2010-01-2088/

https://www.sciencedirect.com/science/article/abs/pii/S0378382022004143
 
I have a 2015 Chrysler Town and Country and go back and forth quite a bit. I really like to use it on long trips to do a cleaning cycle for the fuel system. I still get 20-22 mpg on E85 compared to 24-25 on E10.

I run it when it is >=$0.35 per gallon difference.

My guess is you have a computer/sensor issue.
 
I kind of thought the country gave up on E85. I don't see it at places I buy gas. But happily for my 4 cycle OPE a few stations sell E0.
It is readily available all over the Midwest. I have been using it in my wife's T&C. It is ~$2/gal versus E10 at ~$3/gal.
 
I own a 2010 buick lucerne with 81000 miles. It can run E85 so I decided over the past couple months to run it exclusively on that. As fate would have it. I didnt drive the car for a couple days and when I went to start it, it idled like every bolt was coming loose and then just shuts off after 5 seconds. After 4 attempts I let it sit for an hour then tried again and it fired up, still idling like an old dump truck and then smoothed out and is running fine but with a check engine light related to engine running lean. Im draining the tank and going back to regular gas. But any idea why a car designed for e85 we would do that? The only thought I had is god only knows how old the e85 was that I got at the station as I bet its not cycled often.
FWIW, our van sat for 2-1/2 weeks with E85 in the tank while we went to Alaska. I'm thinking you might have got a bad load of fuel. I wouldn't blame the E85 until you identify root cause. I have been using E85 almost exclusively for 6 months with no issues.
 
Call me confused...

OP states I've been running E85 for months.

The car sits a few days, and its automatically E85's fault the car started weird and threw a code?

May want to start by troubleshooting causes of that code before flipping to it being the fuels fault... at least that's where my mind goes... if it happened out of the blue right after changing to E85 or right after a fill up, then I might go straight to the fuel...
 
Back
Top Bottom