This issue for me started about a month ago. My very first start in the morning is really rough. After the engine is kicked over, the idle is really rough and sometimes stalls out. Battery does not sound weak but rather my engine sounds like it's choking. However, after the first start it seems fine for the rest of the day.

I first talked to some collegues and they have said that many other types of cars (e.g. SRT-4s, Subarus, Lexus) are having the same problem. People in their forums are suspecting that it may be due to the E10 ethanol gasoline (10% ethanol, 90% gas). I brought my car in to the dealership and says that a few people have also been complaining and the dealer too suspects that it is caused by E10 gasoline which has recently been distributed. I've searched the forum and couldn't find anything similar (I apologize if there is). I guess I'm wondering if anyone else has seen this issue?. I live in the Northeast which may be adding to my problem due to the weather.

 

Ethanol-based reformulated gasoline easily absorbs water, so it cannot be sent in pipelines to terminals and then trucked to gas stations like conventional gasoline. Instead, the gasoline and ethanol are sent separately to avoid water contamination and then mixed at the terminal. If they don't mix it correctly, you get water into your fuel system, screwing up, well..........your entire engine.

 

recently I've been also having rough starts and I was also wondering if it was the E10 gasoline. Only morning starts the engine idle is rough and idle cold engine idle RPM is 100-200rpm higher than normal

 

ive been having this problem in the morning too.
im going in to the dealer next saturaday to fix it.

 

you guys have E10? where do you get E10? I've never seen E10.

 

It is most likely not called E10 at the pump. It is the blended gas in certain regions that helps keep smog down. Used to be MTBE mixed with it but the good old government decided not to protect the oil companies and instead push for ethenol to be added since it is better for the environment if it leaks into the ground.

 

what octane rating do you guys use?
i always use 93.

 

its 93 octane and 10% eth 90% gas. It was recent in the market, to help lower price of gasoline and to protect the environment.

 

right now, 91 is the highest that is available to me so that's what I'm stuck using.

 

I use 93 and have never had starting or idling issues. Car has 49,000 miles on it.

 

I am using 93 octane. On the gas pumps, there are stickers that say 10% Ethanol. I already brought my car to the dealer and the guy stated that there is no current fix / workaround.

 

same issue here also. car starts out very rough in the morning and gets worst if I back out of the garage right after starting the engine. the whole front end shakes and engine makes a loud pinging-like sound that i can feel it thru the steering wheel. i only use 93 octane but every gas station that i've gone to seems to be using E10.

 

apparently, Ethanol burns at a lower BTU. It sounds to me like once the engine warms up, when using E10, everything is fine. I wonder if there is a connection.

 

Ive also had the same problem...living in NYC though theres been ethanol in the gas long as I can remember or maybe I wasnt really payin attention

 

by the way, guys... according to my friend, the AMG engineer, you'll get the most power out of your engine using the fuel it was designed for.

Octane is a measure of how much fuel can be compressed without combusting. If you use a low octane fuel in a high compression engine, you will have the fuel detonating on its own, before the engine wants it to. This causes "knocking" and our cars have anti-knock sensors that will detect and adjust the engine to prevent knocking. However, even a little bit of knocking, particularly in a more cheaply designed car, can be devastating to the engine. Its very very easy to totally bugger up your engine this way.

More pure gasoline does not mean higher octane. To reach the octane levels that we are putting in our cars, especially in areas that have octane levels as high as 95 or more, the gasoline has to have large amount of additives that have higher octane levels. For example, pure Ethanol has an octane of 113. These additives do NOT neccesarily make the gasoline burn "better." Ethanol and MtBE are both oxygenates (they add oxygen to the mix) and so cause a more complete combustion, reducing carbonmonoxide emissions. As of 2005, the US federal government no longer requires oxygenates be added to fuels because of the negligible impact on emissions in modern vehicles.

If oxygenates have a negligible impact on carbonmonoxide emissions in a modern engine, that would imply that the oxygenate is not increasing the amount of gasoline that undergoes combustion. So, what is it doing? Combusting? Well, yes it is combusting along with the gasoline. But, does that actually HELP?

Back to ethanol. Ethanol burns at a lower BTU than gasoline. That means that it's burning cooler. Ethanol produces would have you assume that this is "better" because it doesn't "wear your engine" as much. But, how do our engines work? Gas burns, releases heat, expands inside the cylinder, piston is displaces by expanding gas. Basic gas laws state that as temperature rises, volume increases. So, burning at a higher temperature means the piston is being displaced with greater force. What does that mean for Ethanol? It means Ethanol is not as potent as gasoline. So, for every liter of gasoline that is replaces by ethanol, a little power is lost.

Conclusion- increasing octane beyond what an engine requires can LOWER horsepower.

 

all the gas stations along 65th street are all using E10 gas right now. since you met up with C230_05 near there i assume ur around there lol

 

Im in the interior of Bay Ridge a bit more, but I tend to go to the gas stations on 4th Ave in the 90's streets.

 

This is not quite right. The use of oxygenates in gasoline (2%) was mandated in 1990 under the Clean Air Act. Gasoline manufactures overwhelmingly chose to use MTBE (methyl tertiary butyl ether) for it's obvious advantages over ethanol. However, there have been growing concerns about MTBE due to its presence being detected in some ground water, thus contaminating the water. A lot of local areas (such as CA) enacted phase outs of MTBE as an additive. Such measures have been taken in something like 21 states already, and Congress is playing with the idea of a federal ban of MTBE. However, the standards of the 1990 act must still be met which is why the switch has been made by most refineries to an 10% Ethanol Blend.

This is absolutely correct, but there's more. Ethanol blended fuels will actually decrease the efficiency of the engine as well. The common blend being used now, E10, will lower your mpg anywhere from 5-10%. The new "Flex Fuel" cars which can run on regular gasoline, or a high Ethanol Blend (E85) will see as much as a 25% decrease in fuel efficiency by running on Ethanol. Its funny how GM never tells you THIS important fact in their marketing for flex fuel cars when they have all of these "earthy-crunchy" people running around in yellow tee shirts talking about how "nice" it is that we can made fuel from corn.

 

Hey jamoke, you're not alone my car had the EXACT same problem. (2005 C230)

I recently got my car back from the dealer on tuesday, it was in the shop for 2 days.

Here's what I remember the service order saying (I can post it if anyone needs it):
Checked Fuel Pressure - OK
Checked Vaccum Pressure - OK
Checked Started - OK

Replaced all Spark Plugs

I also thought my car may have had a bad tank of gas. After the dealer, I also went to my regular gas station (they are E10) and put in 93 as well as my typical Mobil Fuel System Cleaner.

The car is running much better and will not stall on cold starts.

 

What I find interesting is that the people reporting this issue are from the Northeast. Massachusetts, New York, Connecticut. Is this coincidence? Is anyone else, not from this area, also seeing this problem? Hasn't E10 gasoline been out in California for a while?

On another note, I did one thing this morning (may be a fluke). I turned my key to the ON position but did not attempt to START the engine for ~5 seconds (I'm guessing this gets the fuel pumps going). At which time, I attempted to start the engine and it turned right over without a problem.

 

Yes that will also help. Its something I do as well.

However it was not helping me last week when I was having the stalling issues with the car.

 

And my wife and I normally do this as well while we wait for the seat to get to position. Turn key to on and seat starts to move tro preset position, we are both short so it only goes so far and we have to then push the button for the remaining inch for me and few inches for her. Then start, she fires up every time and has never stumbled.

For my 190E if I use Mobil/Exxon my idle is silky smooth, if I use other gas it is a little more lumpy. Not bad but a noticeable diference.

 

Well seeing how your car is designed to run on this fuel type, I dont see what the problem could be.

 

I'm having the same problem

 

my guess is that it's somehow related to temperature of the engine:

-only happens to people in colder climates

-goes away after engine warms up



What I cannot fit, but is probably the key:

-doesn't happen if the key is in the "on" possition for a time before starting


Anyone know what exactly happens while the key is "on" but the engine is at rest?