[Neill222]

Ok car was running fine. I leave the hosue the morning and after a minute I noticed the yellow engine light is on. I then notice it's driving a bit shaky. I did put in 89 octane and it was running with less power so I was actually on my way to put in 94 pure gas (no ethanol) to bring up the octane when I noticed the light on and turned around.

What are my options here? Should I get it towed in? Drive it in? Drive to the gas station and put in the 94 and see if it makes the light go out? I noticed on another board that the light means underpowered engine or something but this appears to be a Canadian symbol and it's a Canadian car. Pic attached. Thanks! Hoping to get some replies!

[e90coast]

Do you often put that low of an octane? If so, there could be a problem.

[Neill222]

maybe due to the oxygenated gas in Oregon loosening up particles in the gas tank? And then clogging the fuel filter? I know that's a huige problem and oxygenated gas has to be avoided when possible. I was using 89 octane for a while for probably 8 fillups then switched to 91 and it ran WAY better. Then I tried 89 again to test MPG on the freeway and it ran terrible so I was about to switch back to 91 / 94 (you can get 94 here at a gas station I know). Then the indicator came on with about 100 km or 62 miles left to go in the tank.... I wanted to switch permanently to 94 but this happened on the way to the gas station... hmmmmm you think I can drive down and put in the 94?. No more low octane gas for me. It was meant to be a test since the book said you could do it. But power off the line is WAY better with 91 octane. And, can't wait to try the 94.

[Neill222]

wow look what I found on this:
http://www.bimmerfest.com/forums/sho...d.php?t=680969

[Neill222]

"Thomas Plucinsky, BMW Product and Technology Communications Manager told us all BMW engines are designed to run on 91 octane. All performance testing, including EPA emissions and fuel mileage, is done with 91 octane. However, though BMW is all about performance, their motors will run on 89 or 87 octane without damage. The knock sensors pull the ignition timing back and eliminate detonation. There will be a loss of power and a decrease in fuel mileage, but the size of the horsepower loss and the increase in fuel consumption depends upon many factors, such as ambient temperature, exact formulation of the fuel and driving technique, so BMW does not offer any estimates for operation on lower grade fuels. One not so obvious concern, Mr. Plucinsky noted, is the type and quality of additives the gasoline companies include in the fuel. Premium gasolines may have better additive packages which are more effective keeping fuel systems (particularly injectors) clean and working efficiently, than those in regular grade fuels or off-brand products. Using lower octane or off-brand fuel could be degrading the fuel system over time, setting you up for a repair bill down the line."

[e92_enthusiast_1]

I'd try some octane booster and a bottle of techron and pray it goes away. Better yet take it to get the code read. It may be complete coincidence.

[X_Drive]

That is the symbol for the check engine warning. The equivalent of the US "Check Engine or Service Engine soon"
Place it on a reader and see what comes up. And Yes you can run lower than 91, however for optimum engine efficiency and performance, 91 is recommended. The fault could be due to poor fuel or could be something non-relating.

[VTECaddict]

It could be anything. There is no way to tell without getting the code read.