I thought I had bit of a sulfur smell the other day. Heat here is just ridiculous and was a bit concerned. But my tech checked me out, and I have no codes, CE lights, alll good. He says they have several customers recently complaining of sulfur smell, and they think it's unburned fuel from crummy gas. Which leads me to my question--do you think your 65/600 or 55 runs better on a particular type of gas? I 'm really skeptical of this ethanol thing, but can't seem to find a brand that doesn't have it. It is SO hot here (temp indicator said 113 on the parking lot this afternoon), I just figure anything that burns cleaner must be better. Anyone have any evidence or preference on a brand? Or a suggestion on a brand that has less or no ethanol?
Also, are you using fuel additive (techron, etc.)? Thanks in advance...

I'm a big BMW and Benz guy. It's pretty much all I drive. 91 octane is a must. I also ONLY use Chevron. I can count the number of times I have had to "settle" for another gas on one hand. I swear that my cars run better on Chevron. I can only locate 91 octane since I live in Phoenix/San Diego, but if I had 93 available, I would use it.

Speaking of octane, there are a few 76 stations around here that sell 100 octane. I'm in CA so premium is 91. I've read that some people blend the 100 octane with 91 to achieve a 93 octane. Is that safe for our cars? Does anyone know how 76 is boosting the octane?

There's a off-brand station near me that has an assortmant of high octane gas. The station isn't near a race track so I have no idea why they are doing this.

http://www.yelp.com/biz_photos/LRzSa...EkMwwYxByQX3qA

I've found a list on the internet of stations selling non-ethanol gas by state. Surprisingly, there are about 5 in my community. I'm more concerned about that than nything. This is corn--can you imagine what this could do you these complicated sensitive fuel system parts?

My 65 has stinky exhaust on occasion. This is normal as all 65 cars run rich from the factory. It is safer that way...

In the northeast corner of the tri state area and NE this the gas of choice. They include Techron to offset the ethanol. If you patronize Stop and Shop supermarkets or get a Shell card you get a discount that mounts up. Other brands I use are Hess, Chevron, and sunoco.

I avoid Irving, Citgo, and Lukoil. Crap socialist gas!

Btw I believe we are suffering from a changeover from winter to summer formulas so all the crap is coming up from the bottom.

Both Toyota and Honda have run Audi 5000s thousands of miles to see what parts need changing in a modern car to avoid so called ethanol corrosion and the problem was corrected and documented years ago. Keep your car in tune, use proper gas and Techron and you won't have problem.

I had similar symptoms a few months back, sulfur smell, slightly rough idle etc. My dealer claimed to see a Check Engine light while I was in for some other work, although I never personally saw it.

Mercedes has released a TSB for the V12 and "Ethanol fuel corrosion" for 2006 and older cars. The fix is to replace the tank fuel sending unit, fuel pump, fuel filter, and pressure regulator with new improved parts. They insist on replacing everything in the TSB at once and then cover the fuel system for 24 months.

They did the TSB to mine last March, and the symptoms all went away. Cost was not cheap, but my warranty covered everything.

I have used exclusively BP 93 in mine since day 1, it likely has some Ethanol these days, but is the best fuel in my geographic area.

I used the highest octane possible [91 in the bay area] and avoid the non branded stations after couple of times I had a CEL as a result of a "bad gas".

As for whether higher octane helps, I sometimes bother with blending the 100 to arrive at around 93/94 which is probably what the car is tuned for.

Whether one can tell the difference is a different question, though I convinced myself that it's a little noticeable.

Is a way you or someone could post the number and name of the TSB? I would like to see if my 05 CL55 is covered. I have an extended Warranty.

I too, suffer from this sulfur smell. I only started noticing it this calendar year. So much so, that I spoke to my tuner to see what he thought about my tune being too rich down low. The smell comes and goes, and is most noticeable ant idle and after romping on her a bit. I never bothered to correlate the smell with the fuel station I used for that tank, and the amount of ethanol that station used. I will now.

E, you've got PM!

In my experience all amgs make this sulfur smell after a quick romp, dont think it has much to do with the type of gasoline just the current abundance of fuel caused by a heavy foot

I was told it doesn't matter what gas you put in, your ECU will adjust to
suit it, so performance should be the same. However I still put 97 ron in
mine.

I have never had a 'sulfur' smell. The SL has a very distinct odor, but no sulfur.

I primarily use Shell, Mobil or Chevron. But I have used Costco.

feel better now about the odor. I do think I'll try to use non ethanol fuel when I can, and always the best grade that I can (which of course I'm sure we were all doing anyway). The TSB sounds interesting, though I'm not sure it's worth lots and lots of dollars. I've always been leery of repairing things that aren't broken, when they seem to be working well. I didn't hear much about people using additive however, even though I've always used Techron. Thanks to all for the replies. Keep it coming..

Mixing in some higher octane is perfectly safe. I run a mix of 93 and 100 for track days. Not so much for extra power which is a highly debated subject, but instead for a bit of detonation insurance. Just make sure the 100 is not leaded.