I picked up my S2000 today from the dealership service department, after they reinstalled the door panel, did a state inspection and cleared the CEL. Turns out the CEL was a mis-fire code on #4. Since I did a search on this problem I went in prepared with a few questions on why this occurred. Their response: It was caused by "winter gas". "Excuse me?" was my disbelieving reply. The "service" guy went on to explain that the gas in winter is different than summer, its got more "stuff" in it. Um, okay. When I asked to explain the "stuff" he said "it has carbon particles and things like that". My next response was going to be, "so do they change the gas when the time changes or is it more in line with the equinox?" My dear husband who knows when I'm about to say a sarcastic comment, quickly said thanks and grabbed the keys.

Now, I'm not an expert but I'm fairly versed in the mechanics of the car and this guy was giving me a line of BS.

 

We have different gasoline blends in winter in this part of the country. I'm not a petro expert - but I'm pretty sure the winter gas is blended to be more volatile. For a while we also had different anti-polution formula in the winter gas.

I dont' think that had anything to do with your CEL though. That sounds like crap.

 

You may want to have them document your visit.

If I recall correctly the #4 cylinder is the one that has had problems in the past and it may be due to poor lubrication from the two-holed banjo bolts. If this is your car trying to give you a sign as to what's to come in the near future you may want to have this documented so they can't sight your engine failure, should it occur, as being your fault.

 

Gasoline is re-formulated for different seasons, and can cause driveability problems. Do you buy from pil company stores, or places like 7-11 or Sheetz? I have a reason for asking, and will tell you if you answer.

 

I doubt that you would have had any "winter" gas in your tank last week, assuming you drive normal miles.

EPA regulations require that wholesale gasoline terminals (such as in Charlotte) have all "summer" gas in their storage tanks a month prior (May 1st) to the time "summer" specifications kick in (June 1st). This lead time is to ensure that local gas stations have the proper spec product at the local level (June 1st). Thus, all the "winter" gas needs to be drawn out of the terminal storage tanks to make room for the "summer" blend. Since this switching fete can't be accomplished overnight, the Gulf Coast refiners start shipping the "summer" spec gasoline in April.

What is most different about "winter" gasoline is the RVP (Reid Vapor Pressure) which makes gasoline more volatile so your car will start in the winter.

 

Interesting. I did not know there was such a diffrence in gas. But I live in NC where the weather is mild- it barely gets below freezing and that is usually in January. Would the gas be that much different?

And I usually fill up at the same station about 90% of the time in town- a Texaco/Shell, and when I am on the road its usually a Texaco or Exxon station. I go to the same station because they have a 96 premium. Can you believe it is 2.12/gallon.

 

Well, there really isn't too much of a difference in winter and summer mixes as someone stated earlier. Certain companies might do other things to winter blend gas but for the most part it is basically the same. Winter diesel fuel is a different story but we won't get into that...

While I have read nothing about the problem honda606 is refering to, his advice is sound. An actual CEL from winter blend gas sounds fishy to me. I could see it possibly happening, but I certainly have never heard of it happening.

 

I live in a place that gets "real" winter and I thought that the main difference (and I'm sure there are other differences) was the inclusion of a gas line antifreeze (mainly methanol and/or ethanol). RR may prove me wrong on this.
I have run fuel with 10% ethanol (in winter) with no adverse affects (ie. CEL) in this car for as long as I've owned it.

 

[QUOTE]Originally posted by xviper
I live in a place that gets "real" winter and I thought that the main difference (and I'm sure there are other differences) was the inclusion of a gas line antifreeze (mainly methanol and/or ethanol).

 

Dunno if the reason for asking was explained in a PM, but I would have been curious to know. (question WAS answered....)