Actually, I'm asking for my friend Zayed in the UAE who asked me the same question only in a slightly different way and I want to get Jonathan's updated answer on it. It's always good to know all the different ways to break the rules.:P

BTW, our gas here in California is already 10% alcohol.

Always good to hear from you Jay! Regards, Eric

Thnx Eric :)

Now how come u have 10% alcohol in ur fuel man!!!!
well i still haven't added the alcohol as i havent had the time to fit the wide band O2 to the c36, Its still on the poor W124, but i gotta take it off soon before i need a new sensor :P

and yes its always good to learn, my bad on that one.

Many gas stations in the USA are now supplying fuel with 10% ethanol, which allows a higher octane rating, and usually doesn't have much impact on power or economy. I've been using 93 octane for a while now from the local Shell station (remember, USA octane ratings are R+M/2, not the same as in other countries).

Please don't confuse ethanol with methanol... ethanol is fine, methanol is not. Methanol causes all sort of problems with rubber seals & hoses, etc... nothing you'd want in a street car. Ethanol is neat stuff, very safe, non-explosive, you can't even light a puddle of it with a match.

:hat:

On an LH, yes I think it'll throw a code and likely put the computer into some default (and likely lean) map.. I suppose you could play around and find out though :-P

Ethanol..Ugh...Don't get me started on that debacle.. Also, since they started putting ethanol in the fuel full time here I've been replacing EHA seals like it's going out of style.. I used to replace a 1-2 sets of seals a year, now it's the norm.


Jonathan

Jono, I have had zero problems with the ethanol blends on my LH cars, been using them for a few years now. Is it just a CIS problem? I assume that the new EHA seals work ok long-term, it's just the originals that don't like alky, right?

:stuart:

Not sure yet..and yes, I've only had trouble on CIS. I haven't had the new seals in Long enough to be 100% sure, but I'm keeping an eye out:)

jono

Hey guys, are these EHA seals a possible reason why my 88 CIS-E 3.0 300E won't fire? It has spark but it won't fire.

Jay, to answer your question, they put the alcohol (ethanol) in our gas to reduce emissions and to reduce our dependence on foreign oil but there are many who are convinced it does neither. As you can see from the above, there is very little agreement on the stuff. Regards, Eric

Regarding ur EHA, if the seals are done for it should leak fuel. Well atleast thats what i had on the old w124 300TE we had.
Luckily i have had no trouble with my current W124 since ownership back in early 2000 and some 250000km away.

As for the ethanol well it makes ur pump gas into race gas, too bad u cant mix more than 15% of it into ur tank without killing every rubber seal, or hose. and u will need a retune to make use of such a high %.

I used the stuff on my 300 TT thru the Alcohol injection kit, and it did wonders, my friend now has my kit on his bone stock Mitsubishi evo 9 and the car is making over 430hp from a bone stock engine and turbo. but he is at 33% alcohol to fuel, and for sure he has re-flashed his ECU to correct the AFR and up the timing to gain that much power.

I want to try the CTS mod on my 88 M-103 now but it's been sitting too long and now it's giving me a bit of trouble. Maybe some of you know what the problem is? Here's the thread: http://www.peachparts.com/shopforum/tech-help/244582-88-300e-m-103-auto-turns-over-wont-start-post2239365.html#post2239365

Please weigh in with your thoughts. Thanks.
Regards, Eric

Well been playing around with the M104 C36AMG and for the first time i heard incredible amount of knock. I couldn’t believe what I heard, the first time I ripped it up it was in a small tunnel and the sound of this engine is gr8 but something was off. The sound had that familiar knock I used to hear when I first boosted the M103!

I thought this engine had knock sensors, and if you check the engine test logs on the DAS star you will find that the ECU pulls timing per the cylinder that has knock and not just dial the whole map down. SO why on earth then did it knock so hard and so loud. I mean I have test pipes in place of the cats on this car, and its loud, loud enough at least.

Any way this proves that the CTS trick does up the timing significantly :) and thus now I need to install the wide band cause it seems ill need to mix in some alcohol to make use of the trick which will make the car run leaner :( so I need to keep an eye on the AFRs

Maybe you had a bad tank of gas Jay. Some dishonest fuel stations are dispensing "regular" fuel from "premium" pumps. It's been proven time and again here in the states that 25% of the "premium" pumps aren't dispensing premium.

I can't guess why your ECU wasn't able to pull enough timing to compensate.
Regards, Eric

It very much can be, but i do know my gas owner well, and the fuel he uses, but still it can be that.

I think the reason the ecu didnt pull the timing is cause with my trick the ecu reads the water temp at less than 60C' so it just might be that the ecu thinks its a cold start and waits for water temp to rise before it engages full control, like knock and closed loop.

Not sure abt this, just an idea

It turns out I was partially in error on this. The 500E DID get LH in 91 even though the R-129 (500SL) stayed CIS/KE Jetronic and didn't go LH until the 93 M.Y. The 500E was the first Benz to get LH.
Regards, Eric

Hi, I'm new in here. I've messed with CIS for years on VWs and just found this website recently, great stuff BTW. Anyone messed with an adjustable fuel pressure regulator for tuning?

http://shoptalkforums.com/viewtopic.php?f=23&t=114309

You'll almost never see an adjustable pressure regulator on the CIS Mercedes cars. They have a system pressure, a control pressure, and a delivery pressure. Simply raising or lowering the system pressure isn't necessarily going to yield beneficial changes in either the control or delivery pressures. Having said that, I'm not going to say that there isn't any possibility of tuning with CIS pressures. I am going to say that there is a complex relationship between the three that needs to be understood before any meaningful tuning can begin.