C Class W202 High Fuel Consumption

[hmeah]

I have owned a 1994 C Class Merc since 2002, i use to get over 300 miles to a full tank, i am only getting 200 miles now, i have had it serviced 6 months ago, can you help me on what i can do/change to get the fuel consumption up again, i have always used the sames roads and style of driving.. any information is helpful.

Also, my bad window, when it steams up and i put the heater on, it does not seem to be working, what is i need to check/change.

Thank you.

 

[horgantrevor]

the best thing that i can say is get a service done and also i would put an injector or engine treatment in your fuel tank this will clean fuel lines , valves ect and she will run a lot better i can bet on it

i have a 94 c class also and thats what i do and allways works

 

[horgantrevor]

what window is it do you mean back window if so check electric connections also check the fuse number 8 its a 7 and a half amp fuse you will find it at the back left side under the bonnet

i hope this helps

 

[whatever]

i would get rid of it.
IMO you aren't going to find the fault.
I came back from holiday after leaving the car and MB just can't handle that.
I've an A140, but exactly the same problem (see my post)
since then, i had a full service,
MOTOR FLUSH ,ENGINE
NEW OIL FILTER
NEW FUEL FILTER
NEW POLLEN FILTER
4 SPARK PLUGS
NEW AIR FILTER
at my request to see if it made a difference. It didn't.
engine diagnostics recorded no faults.
I reckon it's a computer, sensor fault that MB MIGHT fix or then again cost you £400 + for nothing.

I'm cutting my losses and getting rid of it.
Won't touch MB ever again.
Damn awful cars. :evil:

 

[mightymerc]

hi mate I totally agree with what you are saying dont spend a penny more on it. I have exactly the same problem, and I have done exactly the same as everything whatever has done in terms of service but no result. N.B. I reckon its a computer sensor fault that mb may or may not fix. After 4 hours on mine still no better or difference and £436.00 worse off. Did they fix it. Answer no so be careful personally going for change and new buy 3 series bmw next year wont touch mercedes ever again get well rid

 

[horgantrevor]

all i can say is what grade petrol are you using try shell for a while

if your is fully serviced and had engine flush added to petrol tank and also good quality petrol used

the only thing i can say left is that the engine is 13 years old and may need an overhall
the rings and valves and so on may need looking at . now if you love the car have a go but if not sell her .

i have a 1994 c class and with any old car look after it and she will look after you i do all my own work on her and i have read every thing about her which helps she runs like a dream

 

[hmeah]

thanks for all the input, i will try a fuel treatment.. don't get me wrong, the mercs are very nice to drive and this one has been looked after very well.. i use it in the week and on weekends, i get my audi a4 cab out.. which is nice.. but the merc is much smoother.

i will try the method and see what happens, i think it will help the problem, i am getting oil filter and oil change tomorrow too...

thanks again.. keep on merc'in

 

[kth286]

hmeah

It could be the lambda sensor in the exhaust if it has never been changed.

This device provides the feedback for the amount of fuel going into the injectors.

The device does get less effective over time and on that generation of car it is seen as a replacement item to restore efficiency.

Were your emissions well within the target figures at last MOT ????

You might find that they may not be at the next MOT.

This can cause the garage to try and sell you a new catalytic converter (very expensive).

If the cat has not been physically damaged by a speed bump or the like, then it is often just the Lambda sensor that needs changing.

To be cost effective on that age car you need to know a Mercedes independent specialist that is both familiar with your type of car and who operates on a lower hourly rate.

The lambda probe can seize in the exhaust so is sometimes a difficult job.

Where you located - perhaps we can point you in the right direction.

 

[hmeah]

mmm... i'm in central london... thanks

 

[Aussie Nick]

I would suggest that even the 300 miles out of a full tank is woeful for a c class. I was consistently getting 650 kms out of a full tank in city driving out of my 96 C200

 

[hmeah]

i want to get a oil, oil filter change... and also put some treatment in my fuel tank as its 5k miles since it was serviced...

can you recommed a decent good priced website i can buy the products.. i just can;t get to the shops as working all hours...

appreciate your help.

 

[The Gunslinger]

Did you try changing the Fuel filter?. I dont think it could be causing that much of a loss but could be causing part of the problem....I changed mine in my 560 SEL and i gained 15% in fuel economy.

 

[hmeah]

i have not changed anything, i got it serviced at a local garage 6 months ago... he changed the oil, oil filter, air filter and spark plugs...

if i was to change the fuel filter, is it something i can do myself or would i need to go to the garage, if i can do my self, where can i locate the filter?

thanks

H

 

[The Gunslinger]

Thats a good question...unfortunately Im not entirely sure >.<. I know with the proper tools, the fuel filter on my car was a user swapable item, but I had to temporarily plug my fuel lines to keep gasoline from leaking out...took about 4 to 5 hours...I have no idea what would be involved with doing so on a newer car.

Anybody have any ideas?

 

[horgantrevor]

its located under the car drivers side rear infront of shock and spring under a cover remove the cover and you will see the fuel pump and fuel filter its an easy swap if machinaly minded the fuel will flow a little when disconnected but will automaticlly stop or should when putting in the new filter make sure that fitted in right direction their is an arrow on the new filter . ill try and get picture