Someone please help me! I got in my CLK430 the other morning and travelled about a mile when my check engine light came on and my car started sputtering. I turned around to head home when my car completely shut off (luckily not in the middle of the road). We had to push it back to my house. The next morning my boyfriend started it up and it would run really rough and shut off. He believed it was bad gas and began attempting to syphon it out of the gas tank. When it came out, it was clear and did not have much of a "gas smell." I don't know what to do from here, as we didn't get all of the gas/water out of the tank. I ordered a new fuel filter and we did put some Iso Freeze (I believe it is called) to "dry" out the water. However, it is still doing the same thing. Can someone please offer me some advice? I would prefer not to pay absorbient amounts of money to have it repaired. I would appreciate any advice you can offer. Thank you!

 

Hi,
Water in the gas tank is quite common. Proving that a specific garage has charged you for water rather than petrol/gas is a little more tricky.
In outline you need to drain the tank (remove to get rid of all traces) and blow out the filter, hoses (feed and return) including the injector rail.
All quite straightforward stuff BUT YOU ARE DEALING WITH PETROL. i.e. INFLAMMABLE LIQUID. USE PRECAUTIONS. ETC.

No idea what this stuff is that you have put in but many "additives" will wreck your catalyst. Suggest you don't use anything other than remove all liquid from the system. i.e. drain. Syphoning is not sufficient. (water is heavier than petrol and the tank pick up will pickup water rather than petrol if any water is left in the bottom of the tank (which it will be if you don't get the tank completely empty..

If the CEL light has come on this should clear itself after a few drive cycles but if not you will have to get the fault code read and act accordingly.

Helpful?

Stuart

 

Excuse me, pardon the interuption, but wouldn't it be a good idea to read or have read the fault codes prior to acting upon an assumption that may not be the cause? While I am not disputing what you've advised (it's a sure possibility), but it is also possible that the cause may be somewhere else. The purpose for the CEL and the ability to read the fault codes are so that we can at least begin with what tripped the CEL. JMHO.

Historical trends or occurences and present actual facts may sometimes disagree. I would suggest that you read the fault codes first, before acting blindly, regardless of what may seem to be the culprit.

If you want to check whether there is water in the fuel, simply remove the engine cover and look straight down at the engine and you should find a schrader valve (looks like a bicycle tire air valve), press this valve. If there is water in the fuel, that is the first thing that will come out of this valve. And then you'll know (more than likely). It could also be the camshaft sensor! It could be!!! So, read the codes. That's all I'm saying.

No disrespect meant.

 

Thanks Mr 97dmsr...

Would can you explain a little more about the camshfat sensor. It is interesting for the FORUM.

Thanks

Mario Farias

 

97dmsrS420 - you are on target as always. I know, as an experienced, auto engineer (master degree and +4 years dealer mechanic) and x2 W140 owner, one as a 600SEL, that checking the codes, recording the issues, fixing the computer identified issue, clearing the codes, is always the best and first approach to Benz repairs. If repeats of the same issue occur, repeat the repair process, then driving the car and allowing "running right" operating cycles to set in the computer, as possible. Even if you disconnect the battery after repairing a code fault, and then connect battery and clearing the codes to default, issue free running cycles with no further codes is the only true answer. Water in the fuel does happen, but extensive amount of water in a tank refill, would be extremely rare. Try checking all of the sensor connections on the engine that you can reach. A camshaft sensor error code is possible, and a code reading should assist in confirming. Draining the gas tank, after doing what 97dmsrS420 states in a fuel service valve check on the fuel rail, could be helpful also as the last resort. If necessary, use the drain plug on the gas tank and then add with guaranteed fresh gas of only 5 gallons or so. If you have the opportunity to clean the fuel lines and filter, that may help, maybe. Run engine for a few minutes or drive for a few minutes, if possible, until all the fuel has cycled the system a few times. Drain again, add 5 more gallons of for sure good gas. You should have cleared the fuel system by now. Your spark plugs maybe partially fouled, by now, remove one or two and check. Also check the rest of the ignition and air intake system, cleaning where you can.
Bill Mercer

 

Thanks Bill, for your help and input. In the young lady's scenario she stated:

"I got in my CLK430 the other morning and travelled about a mile when my check engine light came on and my car started sputtering. I turned around to head home when my car completely shut off."

and then, she stated:

"The next morning my boyfriend started it up and it would run really rough and shut off."

Her description of the symptoms (though highly possible), does not lead me to believe it's the fuel (not first, anyway), because there could be so many other things. Which again, because of the Check Engine Light, I certainly would want to know what those fault codes were, before doing anything!

Not long ago I queried this forum when my engine had suddenly started running eratic, and the CEL activated. Sleepwalker told me what to do. My scanner read that I was experience random misfiring from cylinders 3 and 5. When I followed the advice given, I went a step further and looked inside the rubber boot on the coil packs and found moisture. Though I went ahead and purchased new packs, cleaned the boots, applied di-electric grease with a cotton swab, cleaned the plugs (which were brand new), put everything back together, cleared the fault codes; the car ran fine. But, I wouldn't have done anything without reading the fault codes. The fault code scanner has been a very worthwhile investment to me. Because without it, I would've been shooting in the dark without a night-vision scope!

Moreover, Steelergrl also stated that the vehicle engine was eratic and stalled. That lead me to think about the camshaft position, because if I'm not mistaken, a faulty or damaged sensor would transmit incorrect ignition and fuel delivery information, which could result in that type of behavior. But so could a clogged or dirty fuel filter, fouled plugs, mass air flow sensor could be faulty, fuel pump, map sensor, fuel pressure reg., etc. There's just so many things that it could be, until if the fault codes are not read, you're navigating in the blind! And that could be an extremely costly experience.

So, I thank you for your input, and trust that your sharing of this valueable information has helped Steelergrl with her situation. I know that it has me! And I thank you.

 

Here is an update on the problem-- We put the "dry gas" in the fuel tank the other night and let it sit overnight. When I got home from work yesterday afternoon, the car started up and no longer stalls. However, the check engine light still comes on and the car runs rather eratic. I am attempting to drain the fuel and my father is changing the fuel filter this evening. The Mercedes mechanic advised me that if this does not fix the problem, then I should bring it into Mercedes because it could be a bad O2 sensor- or any number of things. I know that there is a bad O2 sensor in the car, so this may be the culprit as well. Thank you all for your help and I will keep you posted.

 

Bad 02 sensors can be a problem. I replaced mine on a 1990s s600, and it did not help. These sensors are expensive. fuel filter change is always good any time. Please check computer codes and more importantly, have a knowledgeable person reset the computer codes. If that is to occur later, keep on track with what you have done to date. We want to help you. If no gas tank drain exists?, get real good gas in there soon, at a small quantity, 3/5 gallons or so; and then get that cycled through your car by driving it. then, get new gas put in at another 3/5 gallons only. Please check all of your engine wire connections for clean connects, no moisture, etc. Try and drive this thing for a few miles. clear the computer codes with battery disconnects, and, checking the error computer codes, and keep trying.. These cars are well designed. try all options before a major repair action.
bill mercer

 

Hi,

No offence taken but understand where i was coming from when I responded.

I absolutely agree that if the check engine CEL comes on the information from the diagnostics is extremely important in determining what is wrong. Presumably in this case it will be a misfire (won't take us forward much) or similar but of course the code could easily be crank sensor or many other faults.

HOWEVER, firstly you need a scan tool (if theyt had one I'm sure they would have used it) and secondly the owner specifically suspected the gas to the extent that they were trying to remove it. The reasons for this were not specified.
.
I responded to the fact that the post was trying to syphon the gas from the tank. A process which would NOT have resolved the problem if indeed it was water in the fuel.

I should have included your additional points which are absolutely valid.

Stuart

 

I hear you, Stuart.

I believe we're all doing what we can to assist another member of this forum to continue there Benz journey. All information is valueable and perhaps even relative. So, no foul.

One thing we all should remember, and that is; when we stop at those rural country store gas station-general store type establishments, most of them have foul, watered-down, contaminated, dirt-filled tanks. And after a good storm, whichever station you see with standing water in the area, they are subject to have junk in the tank if they haven't upgraded them. Most have, but there are still a great many that haven't. And when the new gas is put into the tanks, it just stirs all of that crap up! And the water (which I believe has been said) is sitting right on top! So, beware. Just another feather for your quiver.