Faulty gas gauge
 

Have to bring in my car for service. My faulty gas gauge and its sensors are pretty much rocked. So I brought it to my mechanic and he said theres a lot of problems with them and it should be replaced cost 400 parts and 200 labor. They said they have to replace some lines and the sensor and the filter. The problems all started when I used TECHRON. I never used it before! But I have used STP fuel line cleaner and all that gunk intermittently before. The symptoms first appeared: it wont let me fill up all the way at the gas station only fills up to about 3/4. Then driving and shutting off its at full. Then driving some more the gauge falls back to 3/4 again watching this is very disconcerting as I could actually see it dropping!!! LOL Oh and my command unit is flashing "fuel" when I know how much I put in and how much I usually get driving around. I always reset my mileage in the instrument cluster and I usually get between 280-330 a tank. This was about 3 weeks ago and just as it seemed to fix itself..........now its acting up again to bad my warranty ran out. Anyway this is just another problem I've had with this wonderful car! :smash:

...You know---I NeveR understood how the fuel gauge works either! Here are couple of things that make me notice then follow w/ a "hhmm..?" in my head...

*Tank filled up...sometimes it(overhead info) reads, i.e. 676--other times 702--and 787...760...710...etc.
(I thought when you fill the car up--it should--everytime-- read almost the same as always--not fluctuating the way it's indicated)

*Fuel gauge reads 1/4 before stopping at a mall(or whatever/wherever)--come out...start the ignition--fuel gauge reads 1/2....and sometimes the other way around.

I noticed these--couple of months--after I drove the car out of the showroom...I talked to them over the phone....they seem to think it's normal.....Is it?

Welcome, my friends, to the W163 fuel sender woes. A whole lot of us have already done this or had it done. It involves removing and replacing the fuel pump/sender assembly and, on older models, upgrading a couple fuel lines and filter. Good time to change the filter anyway. I did mine myself for about $350 in parts. Dealer wanted $750 to do it. Search the forums, you'll find LOTS of info on this subject.

PaulX608...are you writing to say that--it's not a "normal function" w/ my fuel gauge/reading/sensor? Please let me know--thank-you!

I would not accept that for normal. I would demand that the dealer do something about it if you're still under warranty. If your problem is the same that a lot of us have had, it's going to require replacing the sender which is integeral with the pump. It's inside your fuel tank. Getting to it is a good bit of labor, but several of us have done it ourselves. Like I said search the forums, you'll find plenty. The first symptom we had was that the guage did not read full after fueling. Then sometimes it woul fall to Empty. It eventually stopped working all together. But, to answer your question, I would not accept that type of gauge malfunction as normal.

Darn it to heck!!!!...Son...of...a......

Thank-you for the info, PaulX608! I really appreciate that! I'll get on w/ these nincompoops to get 'em fixed for me!

Cheers mate!

Hey Reynaldo....that certainly is NOT acceptable operation for a fuel gauge.

For other's edification, my pop's ML had the same problem with his fuel gauge. Fortunately, his was covered under warranty.

For me, and my C43, the problems recently occured (not under warranty to boot). It was at a half tank about three days ago...filled it up and the gauge reads 'zero'. Drove about 140 miles and the gauge works again :crazy: Anyways, ordered all the parts, the W202 has two sending units I need to change. Trying to psyche myself up to tackle it....the blasted access to these units is from underneath the friggin car. :rant:

I feel ya StapleGun. To do this on the 163 requires removal of the back seat to gain access to a sealed cutout in the floor so you can get to the tank. Took my son and I about 3½ hours total. But I did save $400 in the process.

Faulty gas gauge
 

There are many causes for the fuel gauge to mis-behave. If you have warranty, you better have them fix them because it will cost you a lot of money to fix it without warranty..

If it is the fuel sender, then the problem tends to get worst with time. If it is the instrument cluster, then it seems to be more random..

My former 2001 ML 320, had that problem and the gauge became totally unusable after a couple of months..

Appended is some more info...

AC

Thank-you so much for taking the time to provide me the info!

...However, when I fill up the tank--the gauge does show "Full".....The issue is, that, after driving for few days...the gauge, for instance, indicates 1/4 left..then I would park(at somewhere--to do something) for awhile...then would get in--to drive again--this time it would indicate 1/2 full. This, is when I go "Hhmm..?".....I don't understand how it was 1/4 then back to 1/2....then back to 1/4--w/ in a short distance of driving afterwards. Of course, it just happens randomly. Quite puzzling to me! As for the overhead info(trip mileage)--it never the same when filled up--never came close to the same reading.
I hope, w/ this specicifc explanation, someone might be familiar with the issue...and might be able to direct me to the solution.

Faulty gas gauge
 

If I am not mistaken, the trip computer uses the latest computed mpg average and uses that latest average parameter together with the current gas tank reading to calculate the total number of miles/Kilometers left on a tank. That is why if you are taking a long highway trip and you refill, you will have a much higuer number than if you have been driving on the city and you refill.

On both my former 2001 ML 320 and my new 2005 ML 500, the trip computer miles-until-empty-tank reading option seldom showed the same number whenever I filled my tank. It always varied depending on how I droved prior to refilling.

The fuel gauge problem reading error's or lack of accuracy is a well known ML problem caused by either problems with the fuel sender or the instrument cluster (needs a flashing or needs to be replaced) or both.

Even on my 2005 ML 500, I had to have it serviced at the MB dealer, a couple of months ago, because it was jumping 1/2 to 1/4 tank whenever it wanted. Since the dealer flashed the instrument cluster with the latest version, I haven't had any reading errors for months..

AC

Thank-you, AC ML!

All done! Real annoying kind of work too. I watched the mechanic at my shop do it. They had to take off one of the wheels take out the back seat and remove this huge fuel pump out of the floor. New filter new lines new pump and sensors. 3 hours work and 800 bucks later seems to be working.

Holy crap!!....800 bucks!?...

Faulty gas gauge
 

Changing the fuel sender have a huge labor price since the mechanic has to expose the fuel pump mechanism and sometimes he has to upgrade some additional parts if you have an older ML..

Flashing the instrument pannel is straigth forward and is not labor intensive.. Normally it is either the fuel sender or the instrument pannel circuit/logic/etc but not both...

It's a TSB (Technical Service Bulletin) for a known problem, so some dealers may do it free for you.. Even if your warranty has expired.. Though, you don't find too many decent dealers around anymore..

AC

WOW! I wish i knew that last part and called them and asked before i got it done but who knows anyway. lol

My ML is in the dealership for this fuel gauge and they're gonna flash mine...cost? $125...since my extended warranty did not cover "REPROGRAMMING"...

I also wanted to note that TSBs or DTB are bulletins for the Benz Service Techs, not recalls...so for any dealership to do that for free...well exceptional customer service and very generous!

LOL
The great fuel sender!!! My ML430 has the same problem. Can't even remmeber how long I've had this problem. I would have to do a search since there are many posts on this. Dealership wanted almost $800-$900 to fix. Ha!
So now I fill up and reset my trip meter and keep track of the miles.


here's my symptoms:
- tank only goes to 3/4 full on fill up.
- after 5 minutes of driving the gas gauge will drop to 1/2 to 1/4 full.
- wait a little longer and the gas gauge drops to zero!!! gas light will come on.
- stop truck...let time pass....start her up again...gas gauge may read 3/4 to 1/2 full again.


strangest thing of all.........this gas gauge problem is worse in the summer time (hot outside). In the winter the problem almost all but goes away! Some winter days the needle actually goes to full on the meter after a fill up!:eek: I didn't think it was capable of going that high up!:rolf:

I can laugh about it now because I have lived with it for so long that it has become "normal" to me. Funny how I can be conditioned to accept anything with time, huh?:crazy:

You know, I was more than happy to just deal with it, too. I've had cars with non-functioning gas gauges before. But it drove my wife NUTS! She would put gas in it, then a few miles later she'd stop and put $1.50 in. Then the next morning she'd head for the gas station and put another $2 in it. I kept telling her not to do that, just to drive it and I'd gas it up every 3 or 4 days. She couldn't handle driving without a working gas gauge.

This is correct. DTBs and TSBs are not done for free if you're out of warranty. Only recalls are.

Fuel light flashing
 

Folks, no one has yet address the fuel light flashing problem. There are lots of suggestions on the forum but no one has actually come out with a concrete solution. Ligth flashing when vehicle idling and the CE light comes on what is the solution? Changed spark plugs, FSU + fuel pump, fuel filter and hoses, air filter, gas tank cap etc. and still the same stupid problem which is very annoying. What is the final solution to this silly and annoying problem. Can anyone out there come out with a solution instead of theoretical framework?:

sounds like a leak in the purge control system.

there has been a lot of discussion on this and just pulling the #5 fuse in the passenger side fuse box will reset the instrument cluster and gas guage at the next fill up. do a search and try the #5 fuse reset.

Flashing fuel light and CE Light
 

How do you therefore deal with this problem. Any concrete answer regarding this? Solution is what is needed and not speculations. How do you find the leak in the control system? What do you changed? MB should be smarter than this stupidity. Note 1998 ML320 does not have #5 fuse at the passenger side.

activate the charcoal canister and hook up a smoke machine to where the purge valve is, look for where the smoke is coming out.