tmason

Hi my name is Tim and a new owner to my 1st MB 4matic.I have been looking for one for a couple of years and finally talk my wife in making a change.(12 yrs of Lexus)Purchased from a MD Dealer out of state in "As is Condition" and our 1st fill I didn't see the label inside of the cover before fill it with regular gas.The check engine light came on right after I did this.I had this happen to my truck when the gas cap doesn't seal and same thing on our 03 ES Lexus and put new cap on.Tried to get a new seal or cap but dealer was closed.I placed a another thicker seal on old gas cap and topped off with a couple of gallons of premium but light is still on? Any ideas and thanks for any input. Tim

Efivehundred

If it was a loose gas cap that triggered the check engine light, I believe the CE light will stay illuminated for a certain amount of engine on, engine off cycles.

I think this has been discussed before and a search of this forum will have some good information. Also, have the codes read to determine what actually caused the CE light.

Barry45RPM

I don't know that I would have gone to the conclusion that it was the gas cap gasket/washer that caused the problem. My 1st guess would have been the gas you put in or a loose gas cap. If it doesn't clear after a few tankfulls of Premium, you need to look for some emission item that is out of tolerance.

As soon as you burn thru a half a tank of gas, fill it with the highest octane you can find to average out and elevate the octane level of what's in the tank. Do that twice, then run it out and fill with Premium.

Almost everything can can go wrong with these cars is recorded by the car's computer system & can be diagnosed by the dealer.

tmason

Thanks and I'll keep you posted. The dealer said to take it in and hookup to the computer to see what error is in it. Tim

lkchris

Mercedes hasn't built a car for the USA market capable of using regular gas since the 1980s.

Dexion

^Gas attendant put 89 in my tank by accident once. Didn't seem to have any problems. Been running 93 every other time though.

nopcbs

You can put regular into ANY modern car that is built for premium and exactly four things will happen: (1) the knock sensor will dial back your advance to prevent pre-ignition from damaging your engine, (2) you will be slightly down on power vs. using premium because of the change in the ignition timing to prevent pre-ignition, (3) you may see slightly worse fuel economy...slightly, (4) you will save a little money on the gas you buy.

Since regular tends to have a bit less detergent in it than premium, you may suffer more carbon build-up over very long term use. Throw in Techron every now and then to deal with that.

You are not going to damage the engine and you are not going to see a warning light.

The warning light is classic loose gas cap or worn out o-ring on the cap. It will turn itself off after a while once you tighten the cap or replace the o-ring.

Wait a minute, we are not talking about rot-gutt sub-regular as is supposedly found in Mexico, are we? That stuff is supposed to be so bad it might actually damage an engine.

- nopcbs

WEBSRFR

I have a 2007 E550. Should I add a bottle of Techron when I fill up the gas tank every now and then? Is it completely safe on our cars?

nopcbs

Chevron Techron is good stuff and will keep your injectors squeeky clean if you use it a few times a year in combination with good regular gas. If you are using a good grade of premium, especially Chevron which contains Techron, you are likely already getting a good detergent package and will not benefit from adding Techron.

It will certainly do no harm in a gasoline engine. It will clean up an engine with fouled injectors with continued use.

Good stuff. Not cheap, though.

- nopcbs

tmason

I have an appointment in the morning at MB to look at this light issue and I ordered the new o-ring today for the gas cap.But the car is running a little rough and I'm thinking it might be the lower octane in regular gas?The tank is about 3/4 full and I was going to top it off on my way home with premium to see if this would help? Thanks Tim

WEBSRFR

If you feel that bad about it, syphon it off and use it for your lawnmover and fill the whole tank up with premium gas.

tmason

That is a good idea. It doesn't bother me but my wife went from a Lexus to this because I always wanted an e 4matic and she is nervous if I picked the right car. My 74 e9 CSA will run just fine on this gas

Barry45RPM

I use it a couple of times a year. Get it at Costco or another "Wholsesale Club"... much better price.

nopcbs

I have read claims that an air leak in your gas cap seal can lead to rough idle. Have not experienced that symptom myself. Have gotten the check engine light that goes away. This is an emissions-mandated thing, by the way. The EPA wants to scare you into fixing the seal by making you think you are damaging the engine when it happens so you fix the leak.

If you were unlucky enough to buy gas with a lot of water in it, not impossable in winter where it's cold, that might cause a rough idle. Not very likely, but not imposable. The rough idle is NOT a symptom of too low octane as in regular gas. If you are going to see a symptom (pre-ignition) it will be under load at high speed...and your knock sensor would have to have gone deaf.

- nopcbs

tmason

Thanks Guys I'll let you know after going to the dealer because I want to get that light off.

vettdvr

You are correct. After Katrina here in La all we could get was reg. when it was available. I used it in our E500 but followed the manual by not using heavy throttle or high speeds. Just drove around town and short highway trips until I could bet prem. Remember Reg is better by far than NO GAS>

Loose cap will trigger light. Drive a while it will go off. Don't need dealer.

tmason

Thanks and the light went off last night so I tap off with 7 gallons of premium so things are good. Also I was looking for a tab for the back window screen and was told by the Dealer I bought the car from and also the Dealer here that you had to buy the screen for 1350.00.But I emailed my Dealer just to double check and he called and said he can order that part for 5.72 and to top off my day I used this Forum to figure out my Homelink! Thanks Guys for all the input and thanks MBW!

Silly_me

You mean she went from a gussied up Camry to this. It won't be a cheap to operate in the least

220S

You can run regular and it won't hurt the car. The ECU's anti-knock sensors will adjust timing. Just don't do it on a regular basis because the change in timing is not conducive to the motor's performance. Don't waste your time and jeopardize your health by "siphoning" out the gas. You'll be fine.

But if you don't want to trust me on this, then call: 1-800-FOR-MERCEDES (1-800-367-6372)

btw, gas in Mexico is actually good quality. Magna Sin (green label) is like 91 octane here in CA. They have a higher octane available called Magna Premium (red label.)

PEMEX is a state-run company and there is nothing wrong with their product. And PEMEX run gas stations are the only stations in Mexico. The only exception is buying fuel in the middle of nowhere where they don't check the tanks and might have debris (if you're exploring distant rural areas, then carry an extra fuel filter just in case.) I lived in Sonora for two years driving a BMW with no fuel related issues ever.

lkchris

Isn't it amazing how many just "believe" rather than pay attention to data and fact?

The "knock sensor" thing is NOTHING but belief. You know, like "legend," old wives' tale," "rumor," etc.

Doesn't happen.

Find the Mercedes documentation.

220S

In Star DAS there is even a test for the knocking tendency of engine. It knows is whether the car is detonating or not, it pulls timing. If you run lower octane it retards timing to protect from knocking based on detonation. Why do you think Renntech and Kleemann remap the ECU for higher octane with their tunes.

#W0133-1778062 Mercedes Benz E63 AMG Knock Sensor Bosch

E350 4Matic06 Ignition Knock (Detonation) Sensor M272.972
E350 4Matic07-09 Ignition Knock (Detonation) Sensor Engine Desig: 272.972
E350 Base06 Ignition Knock (Detonation) Sensor M272.964
E350 Base07-09 Ignition Knock (Detonation) Sensor Engine Desig: 272.964
E550 4Matic07-09 Ignition Knock (Detonation) Sensor Engine Desig: 273.962
E550 Base07-09 Ignition Knock (Detonation) Sensor Engine Desig: 273.960
E63 AMG07-08 Ignition Knock (Detonation) Sensor

Cory @ Kleemann

KLEEMANN tunes for 91 or 93 pump fuel depending on what fuel is most widely available in your area. We typically never tune for higher octane levels unless specifically requested by the client. KLEEMANN can also do "economy" tunes intended to reducing fuel consumption and/or using lower grade fuel, however, you sacrifice quite a bit of power doing so.

220S

Thanks, Cory. I should have said "Kleemann can tune for higher octane" rather than imply that you do it de facto.