Ethanol and SES light - BMW Forum

longrob · 08-31-2009, 08:02 PM

Could just be a coincidence, but twice now I have used gasoline with ethanol while traveling and got the 4 running lean trouble codes. My light is on now, but got it to go out the first time by running a few tanks of gas with 1/2 a can of Seafoam. I have 140K miles and assume the Seafoam cleaned the injectors.

Anyone else have any ethanol issues?

kbxm · 08-31-2009, 09:27 PM

I have a similar problem with my 2002 X5 3.0 but only during the winter months. If I add some HEAT or SeaFoam the light goes out after about half a tank. I'm just passing 75k on mine.

darkhorse737 · 09-01-2009, 12:13 AM

your engines are not designed to run on ethanol...

and yes as a result of using ethanol, you will get lean codes because the O2 sensors in your cars do not respond correctly to alternative fuels.

darkhorse737 · 09-01-2009, 01:03 AM

ADDENDUM: to my last post.

Notice also how much HOTTER your engine runs on ethanol.... The heat over and above what is considered normal translates to engine performance degradation & engine damage over time.

BMW recommends the correct grade to use for your specific vehicle in the gas door and the owner's manual. I, and am sure, other 'Werkz experts will join me in recommending that you stick with that is specified.

kbxm · 09-01-2009, 08:06 AM

I don't think he's talking about running soley on Ethanol, but on the federally mandated 10% blend. Even though some vehicles can run on E85, I know BMWs won't.

I asked my BMW mechanic a while back and he said US engines are all designed to run on 10%, but from experience you'll get significantly better mileage on pure gas.

Unfortunately here in Minnesota we don't have anything BUT the 10% blends unless you want to look for some very expensive pure fuel. Even that's only allowed in small gas engines (although no one complains if you put it in your car). I've never had ANY issues in my BMrs running on the fuel here again except in the cold weather and the mechanic says it might be water in the fuel.

longrob · 09-01-2009, 05:35 PM

I did mean the 10% ethanol blend; I would never use E85! I normally run on 93 octane with no ethanol added here in Mississippi.

I have read, that often, the ratio is much higher than 10% at stations, which causes some cars intake manifold issues, et al.

I am going to try a bottle of Heet at my next fillup; perhaps I have some water in the gas.

Thanks for the replies.
-Rob