I live in the rural part of Texas and drive into the North Dallas area.

In the Dallas area they sell reformulated gasoline which supposedly has additives which keep the injection systems clean, thus causing cleaner burning engines to limit pollution.

I typically buy gasoline in the country without the additives. What is the best additive I can use on my 300E to clean the injectors. I do NOT need to clean the intake valves because I just put it together with a fresh valve job.

When using such additives in a high mileage engine, how much of the improvement comes from cleaning the intake valves and how much comes from cleaning the injectors?

If cleaning the injectors turns out to help, I may start using the reformulated gasoline in the city, rather than the standard gas in the country.

Thanks for any replies,

------------------
Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Hi Larry,

My understanding is that all unleaded fuel that is sold at name brand gasoline stations already have additives and detergents to clean the fuel system and injectors. You shouldn't have to add any additional additive into your fuel system...save your $.

I always stay away from the no name brand gas stations because their quality is sometimes questionable. That's not to say that they may not mix a bad batch of any kind of fuel, unleaded or diesel. That is why I go to name brand stations only.

Anyway, if the car is running poorly due to high mileage, no additive in the world will fix the root cause of the problem.

Herb
82 240D
107,000

The detergents in gasoline are designed to keep your fuel system clean, so if you use a lower quality fuel or use a lower octane fuel (when your car requires premium) regularly, then it may be a good idea to use some fuel system cleaner every once in awhile. For example, my Integra has a very high compression ratio (10:1) and the manual says I should only use Premium unleaded, well I was cheap and used regular for about 6 months (my engine was knocking like crazy) when I switched back to premium my engine would still knock, I used some fuel system cleaner and the knock dissapeared.

------------------
Adam,
1986 300E
1997 Acura Integra GS-R

Larry:

There are a few folks on another MB list that I belong to that swear by the Chevron Techron Fuel System Cleaner($6-$8) dollars a bottle.
Then again, the head MB tech on that site says there's no need for chemical cleaners. He recommends quality fuel AND taking the car out periodically for a "spirited" drive.

I've experimented with Techron and the Lubro-Moly products and cannot tell if they've helped or not. I have noticed that by using Chevron Techron Premium(93 octane rating in south Texas), I get about 1.5 miles per gallon better mileage than with any other name-brand fuel. My 2 cents.

Regards,

Mike Murrell
'91 300-SEL(M103)

Larry, pick your poison. Yes, there is evidence that most of the major brands have detergents whaich are alledged to keep the injectors clean. How effective this can be is questionable. If it were 100% true, then there would be no need for injector cleaning additives. If your brand of fuel is one of these and you notice your performance dropping or rough running, then the additives aren't doing the job.. I have used STP injector cleaner with an improvement in idle and startup, but, having said that, I guess mine were pretty crummy. All gasolines produce varnish when heat cycled. I used two bottles on a full tank and have never had to repeat the dose. Also added some dry gas as well. I don't think there is any exact science here. If I could get some of the aviation gas they used to use with the piston type aircraft engines, I'd use that as well. There are two trains of thought on octane. High octane numbers retard flame propagation within the cylinder thereby preventing ping or knocking at the expense of less complete combustion. Lower octane numbers burn more readily, but are prone to the above. I have used regular unleaded in my 300 for over 5 years with no ill effects, ie. no pinging, knock or plug telltales. Mileage can be as high as 26 or so w/o leadfooting. I had the emissions checked by a local garage. There is a difference, albeit slight, when running the regular unleaded, CO was lower (can't remember by how much, but was lower). This was a bit of a digression, so, cutting to the bottom line, try the injector cleaner. There doesn't seem to be a downside to using it. Just my $0.03 worth.

------------------
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE

Hi Larry, I use redline gas additive. If used at a rate of 15oz per 100gals on a ongoing basis it costs about 4 cents per gallon. If the whole bottle (15oz) is used as one time clean up, every 100gals then it is still 4 cents per gallon. I use it in my C230 and the wifes' Subaru and we get mileage in excess of EPA calculations for both city and country. In the C230, I burn Mid grade unleaded and have not observed any pinging when I add to each tank at the rate of 1.5oz per 10gals Roger

since we are on the topic,,, i thought it would be a good idea to mention that newer gas stations are better for your car!?!?!?
yes! just like varnish builds up in your cars vital engine parts it also builds up in 20 year old fuel storage tanks. thats something to think about. you would probobly save some money an troubleshooting and fuel filters.
good luck,
adam

------------------
87 300E
BLACK GOLD WITH CREAM INTERIOR, SPOILER, AIRDAM
CLEAR MARKERS

87 420SEL
BRONZE WITH CREAM INTERIOR

I suppose that I wasn't clear regarding my objective in using a fuel system additive.

I just did a valve job so the valves are clean and the compression is as new. I'm not trying to use a fuel additive to get the added zillion horsepower as might be claimed in a J.C. Whitney ad.

I'm also not trying to up the octane. I thoroughly understand the effects of octane increase and decrease.

My objective is to ensure that the injection system flow is not inhibited. In the Dallas, Houston and probably a few other Texas cities, it was mandated a few years ago that they sell "reformulated" gasoline. This has additional additives to keep engines clean, thus in theory, keeping the engines running more efficiently, thus decreasing air pollution. In East Texas where I live this fuel is not mandated.

I have begun since I began this thread to use Texaco CleanSystem3 and Chevron Techron Premium from pumps in Richardson (Dallas area) rather than buying an additive chemical.

In my original question, I was seeking inforamtion regarding an additive that I might use to "blitz" the system, before beginning the diet of "reformulated" fuel for a while.

Power is off some in my 300E, and the engine is by no means worn out as suggested earlier in this thread. The engine has the compression of a new engine. Either the injection system or other engine management components are not working exactly right, or maybe the ignition is not being advanced properly by it's control mechanism. Since there are no mechanical advance mechanimisms, I don't know exactly how to check it. I do plan to at least put a timing light on it, and ensure that the ignition is advancing.

Additionally, when putting the engine back together, I regapped the plugs that came out of the spoiled engine and stuck them back in. I now have a new set of plugs and a fresh fuel filter that I plan to put in while on vacation next week.

Thanks for your responses,

------------------
Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by jeffsr:
If I could get some of the aviation gas they used to use with the piston type aircraft engines, I'd use that as well.
<HR></BLOCKQUOTE>

Jeff,

You don't every want to try that on a car with a catalytic converter. I have my own plane that burns on 100LL Avgas (100 Octane Low Lead). People have asked me if they could put Avgas in their cars to make them run better. I advise them that Avgas will make their cars undriveable because of the lead contained in this fuel. Putting Avgas in a car will guarantee a ruined catalytic converter which I'm sure could get expensive. :(

Herb
240D
107,000

My 300E's head was also rebuilt. One thousand miles later, I used a fuel additive called "BG 44K" that my mechanic recommended and sold me. I felt right away that acceleration improved. If this is all in my imagination, here are some more benefits that I found. It solved my starting problems; the car now starts the first time every time, hot or freezing cold. The car now idles smoother. Good luck

Herb, just wishful thinking. Every now and then I get to pining for the days when gas was $0.25/gal and the RON was 110. I guess the point I was trying to make is that leaded, unleaded, additive, no additive, whatever. All of this kind of reminds me of some medevial alchemy scheme. And I for one, have engaged in this process. Injector cleaners remove dissolvable deposits at or near the injector orifice. I have done this once on my car with an improvement and have never had to repeat the dose. Coincidence or effective performance of the product. Damned if I know!!

------------------
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE

[This message has been edited by jeffsr (edited 11-16-2000).]

Larry,

I've been driving cars (3 Renault Fuegos and 2 Benzes) with Bosch injection systems for the last 12 years and about 1/2 million miles. Never used any additive, never ever had any problems with them. Neither did I ever replace a Bosch fuelpump on any of my cars either. This may just be luck but I doubt it. In my opinion these "fuel system cleaner" products are just marketing gimmicks. Same as the so-called "gas line antifreeze" products up here in the frozen north. Never used it never needed it. And I used to park outside.

Alex