Hi.

I have lived in the greater Seattle area pretty much my whole life. I don't recall ever seeing 93 octane gas... I live in the Fremont area, and was wondering if any of you Seattlelites have any leads on 93 octane. My car suffers from sporatic idle problems and I'm getting sick of it.

I've had a BG44k-like fuel treatment performed, and that fixed the problem for about 3k miles. Now it's back. I've had damn near everything replaced under the hood over the last few years, and I'm tired of throwing money at parts when the idle problem just seems to come back.

So I want to give 93 Octane a try. Anybody? I know there are Seattle people on the board!

If you car was designed to run on 89 octane fuel using 93 octane fuel will do only one thing. COST YOU MORE.
Hope this helps

Higher octane won't do much for the idle quality.

bp,
try running a bottle of tecrolene(?) sold by chevron throught it. try it for every other tank for 4 fill-ups and see if it helps. most city cars suffer from carbon build up on the intake valves wich can cause hard cold start and rough idle conditions. other "fuel system" cleaners claim to work, but tecrolene seems to work the best, but it takes time to work. i have used it in my 190e and have cleared up a hard cold start problem as well as low idle. just my .02 worth but hope it helps.
Joe

Chevron Techron. Good stuff.

You might want to also read through these threads.

Haasman

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'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)

Not sure if they have Sunoco gas stations in Seattle, but the east coast Sunoco pumps have 4 options: 87, 89, 91, 93. 91 works well in my 560SL.
Higher octane additives are put in the fuel to suppress engine knock or "pre-detonation" in the cylinders. Contrary to belief, "premium" fuels generally are not better qualty gasolines, but actually reduce the volitility of the fuel with additives to prevent pre-ignition. High compression engines compress the fuel/air mixture to a greater extent so the concentration of fuel is higer in the combustion chamber. Hot spots in the chamber (like a bit of hot carbon) will ignite the mixture before the plug fires. When the plug fires, the the two burning fronts collide and knock occurs. Not good for the pistons. Rough idle is rarely fixed by premium fuels. The Techron route is better.

Haasman, could you double check your link...I'm getting a blank page when I click on it.

Thanks!

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

AlKraut said: Not sure if they have Sunoco gas stations in Seattle, but the east coast Sunoco pumps have 4 options: 87, 89, 91, 93. 91 works well in my 560SL.
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No Sunoco in Seattle or the Northwest for that matter....and no 93 octane gas.....unless you want to use a racing additive to boost the octane of the pump stuff you are out of luck.

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1986 560 SEL (159K miles)

One thing "I did learn from my self education on how fuel injection works is that the higher rated gasolines burn slower and thus deposit more carbon build up on the insides of the engine. I agree from another post that if you use some Cheveron Trecon fuel injection cleaner when you go to fill up again that will help clean the deposits on your exhaust valves and my add some smoother performance to your engine.
I also recomend having the MAF throttle body cleaned with CRC throttle body cleaner#599c Availible at PEP Boys , Cragen Auto Parts. A lot of junk goes through the throttle body and sticks to the high heat wire that measures the volumn of air the engine is taking in.
This unit can be disconnected from the air hose from the front of the car and spray cleaned and then reasembled.
alot of performance is losted because a mechanic neglected to clean the MAF sensor.Mercedes-Benz has there own version of fuel injection cleaner over the counter .
I hope this helps
Bob Geco
1992 300-E
1968 280SL
1987 ford Mustang LX 5.0 nothback

It's funny that you say that. I've read articles that state this is a common mis-conception. Higher octane fuels burn at the same rate as a lower octane fuel; they just resist combustion more. Once ignition has occurred, the two fuels burn at the same rate. I once did a lot of research into fuels. I've had several computer crashes since then though so those bookmarks are long lost sadly.

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http://images17.fotki.com/v8/photos/...e_fleet-vi.jpg
[ Old 210 E55s never die ... they turn into 202 C55s ][ SpeedyBenz Custom Suspension ][ MBenzNL On Board ]

And so it is.
Higher octane fuels RESIST SELF IGNITION, but are pretty much the same flamespeed as lower octane fuels.
As for the Myth of producing more power, the fact that you can run a little more advanced ignition timing ( older vehicles ), may net you a slight gain in power.

P.S.
Are you still producing rear camber arms for the W 202 ?

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2007 C 230 Sport.

Wow, thanks for your replies, guys. I actually put a bottle of Techron in the same day I started this thread. My understanding is that the fuel-system cleaning that I did 3k miles ago should've taken care of any gunk caked up in my fuel system... The car ran so well after I had this done, but now some of the problems are back... It's as if the engine is missing.

But since I put the techron in, the problem hasn't returned. It just seems wierd that this problem comes back so quickly. I only use premium fuel from Shell and Chevron. I never fill up anywhere else. While now I now that Octane levels don't cause this problem, the additives that come in Shell and Chevron's fuels should take care of this, right?

It's so annoying! Bob, thanks for the hint about the MAF throttle body. Unfortunately, I'm not a mechanic so I have no idea what that is or where to find it!

Bob - that's a myth. Higher octane gasoline does not burn slower. It has less tendency to detonate and detonation consumes the air-fuel mixture faster than normal combustion, but comparing detonation combustion, which is abnormal, to normal combustion is not an apples to apples comparison. Same applies to carbon buildup. Octane is not a factor.

More octane than is required to keep an engine out of detonation has no benefit. The detergents and other additives in gasoline are about the same regardless of octane rating as is vapor pressure.

Also, K and KE-Jetronic systems do not have a hot wire mass air flow sensor (MAF).

Duke

big pete,
pm me with your phone number and we can hook up.... I live in Everett
work on Saterdays but off on Sunday.
Joe