Thirsty C200K

Rock

Member
Joined
Mar 4, 2011
Messages
51
Car
Mercedes C200K
Hi All,

my C200k, 51 plate seems to be drinking too much petrol lately. short and long drives brings 24-25mpg as its giving me approx. 30 miles for £10 petrol.

Any advise will be appreciated

cheers
 

Ponton-Jetronic

Active Member
Joined
Dec 13, 2011
Messages
63
Location
Ireland
Car
W124 200TE
Hi All,

my C200k, 51 plate seems to be drinking too much petrol lately. short and long drives brings 24-25mpg as its giving me approx. 30 miles for £10 petrol.

Any advise will be appreciated

cheers
Is it a blockage or ventilation problem.? What change did you make, or what service was done when it started ? Are you Carb or Injection ? What was your normal consumption [ or per £10 usage ] before this thirst ?
Ponton-Jet.
 

Ian B Walker

MB Enthusiast
Joined
Jun 7, 2003
Messages
7,668
Location
Freckleton
Car
300-24, saloon and coupe, E300 24 valve diesel estate
I would have your car on a Star machine to diagnose the problem. It could be one of many things rangine from plugs to maf and beyond.
 

Ian B Walker

MB Enthusiast
Joined
Jun 7, 2003
Messages
7,668
Location
Freckleton
Car
300-24, saloon and coupe, E300 24 valve diesel estate
Its not a 211 Steve and only has 5 gears :p
 

AMGeed

Hardcore MB Enthusiast
SUPPORTER
Joined
Nov 1, 2008
Messages
13,481
Location
Bournemouth/Poole Dorset
Car
2014 E63 Biturbo
Just drove my fathers C200K to Heathrow and back. Average speed 53MPH, Average 30.6MPG. It took almost 80miles to get out of the 20's per gallon.
 

st4

Banned
Joined
Mar 1, 2008
Messages
14,373
Location
In the driving seat
Car
C220cdi tourer
Its not a 211 Steve and only has 5 gears :p
The 203's after a 210 are the scappiest of the lot. I've seen a few here with holes in the bonnets, wings etc and the rear arches go.

Since you seen mine, its had waxoil from me. Never thought I would do that as I tend to run cars under 7yo usually. Shocking, and its MB that are to blame as its their dealer that repainted mine!!!!
 

mauno

Active Member
Joined
Dec 26, 2011
Messages
306
Location
Braintree
Car
W203 C200K T model classic/ W168 1.4 avantgarde
I'm a c200k owner and give you the answers: if it does not pull like a train when you push the pedal down above 2500rpm,then it will be the secondary air injection system.which includes few sensors tubes and the supercharger all the way down to the exhaust system.It will be a long search.do it yourself or prepared to pay a lot.after i have fixed mine,i get around 35-37mpg
 

tali

MB Enthusiast
Joined
Jun 17, 2008
Messages
1,629
Location
593 West 11th street.San Pedro
Car
qashqai
Quote:
Originally Posted by Rock
Hi All,

my C200k, 51 plate seems to be drinking too much petrol lately. short and long drives brings 24-25mpg as its giving me approx. 30 miles for £10 petrol.

Any advise will be appreciated

cheers


Is it a blockage or ventilation problem.? What change did you make, or what service was done when it started ? Are you Carb or Injection ? What was your normal consumption [ or per £10 usage ] before this thirst ?
Ponton-Jet.

CARB? i thought Merc stopped them with 190 ?
 
OP
OP
R

Rock

Member
Joined
Mar 4, 2011
Messages
51
Car
Mercedes C200K
changed MAF senser last year Nov 2011, its an injection, done B service.
 
OP
OP
R

Rock

Member
Joined
Mar 4, 2011
Messages
51
Car
Mercedes C200K
MAUNO did you do it yourself? im a newbie to all this so very unlikely i will know what to look for. Do u know anyone that cam do it? im based in essex or can come down london

unless your able to give me a step by step guide? the B service is due should i get the andie to check this as well?

email: rokib_98@hotmail.com

cheers
 

mauno

Active Member
Joined
Dec 26, 2011
Messages
306
Location
Braintree
Car
W203 C200K T model classic/ W168 1.4 avantgarde
yes i did it myself. im in braintree. send me a message with your phone nr
 
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OP
R

Rock

Member
Joined
Mar 4, 2011
Messages
51
Car
Mercedes C200K
Mauno, im in Romford not too far.... my number is: 07951 959879

much appreciated
 

tjs_riley

Active Member
Joined
Mar 1, 2010
Messages
71
If you could post the instructions here, it would be great. This problem in something I've been trying to address for quite a while and I am close to selling my car in frustration!
Thanks!



I'm a c200k owner and give you the answers: if it does not pull like a train when you push the pedal down above 2500rpm,then it will be the secondary air injection system.which includes few sensors tubes and the supercharger all the way down to the exhaust system.It will be a long search.do it yourself or prepared to pay a lot.after i have fixed mine,i get around 35-37mpg
 

joe prosser

Member
Joined
Jan 30, 2012
Messages
44
Location
Edinburgh
Car
E 200 estate (W124)
Many times the issue with poor mpg is the ECU is unable to switch from open loop (warming up) to closed loop (normal running). The switch is triggered by the coolant temperature sensor indicating to the ECU that the engine has reached threshold running temperature. Open loop is characterized by long injection times to warm the engine up and to fire up the catalyst; secondary air injection is to provide enough additional oxygen into the fuel-rich exhaust to accelerate this catalyst heating up process. First check that you have coolant at correct level, too low and the temp sensor is no longer in contact with the coolant. Next check that your thermostat is not left jammed open, it should take some time after the engine is started before the top pipe to the radiator begins to warm. If thermostat is permanently open the coolant is circulated through the radiator and the engine will take significantly longer to reach running temperature. Check that your throttle throat and throttle plate are clean of oily grime. Next examine your O2 sensor condition. If caked in black soot it will be unable to detect the true oxygen levels in the exhaust and will report in error to the ECU that there actually high levels present. The ECU will try to compensate by injecting yet more fuel, further exacerbating the problem. O2 sensors can be fixed by using a plumbers gas burner to heat the tip enough for the soot to burn off. Finally check your fuel regulator valve on the fuel rail. Pull off its vacuum tube and check for any dribbles or smell of fuel from it. If the fuel pressure regulator is 'healthy' you will find that, when the car is idling, if you remove its vacuum tube that the car first picks up in revs for a few seconds (the loss of vacuum in the regulator allows the pressure in the fuel rail to jump up, so more fuel is suddenly injected) and then the car will drop in revs and run unevenly (as the ingress of un-metered air via the open tube now begins to upset the fuel air balance in the engine). Replacing the tube now will restore order . If you feel the MAF is at fault simply disconnect it, the car should run on default parameters, not perfectly but OK. Do this simply as a diagnostic to determine unambiguously that the MAF is at fault.
 

mauno

Active Member
Joined
Dec 26, 2011
Messages
306
Location
Braintree
Car
W203 C200K T model classic/ W168 1.4 avantgarde
and if all the steps to make scare the hell out of you,just call me.i can do it for you
 

MarcelKan

Member
Joined
Sep 27, 2011
Messages
37
Location
coventry
Car
C200 Kompressor
Before the service A been done, the average mpg I could get was around 25mpg. After the service A (changed new oil, oil filter & spark plugs, etc.) an average of 30-35mpg now. I have noticed from the cluster board that 15mpg when the engine just started at freezing temperature and up to 27mpg when it get warmed.
 
Last edited:

joe prosser

Member
Joined
Jan 30, 2012
Messages
44
Location
Edinburgh
Car
E 200 estate (W124)
The steps to take are not too scary or time consuming. Do the simplest first:- Start you engine.
1) look at level of coolant and top up as necessary..time taken, 30 seconds.
2) Locate the fuel pressure regulator (FPR) and disconnect the vacuum line. Sniff and look for fuel from the line and FPR and at the same time note any increase in revs for few seconds and then a stumbling idle. Reconnect the vacuum line. Time taken about 60 seconds.
3) Disconnect the MAF sensor and note any changes to idle, then reconnect. Time taken, 30 seconds.
4) Switch engine off and remove air duct between air filter and throttle. Measure Clean throttle throat and plate with WD40 and kitchen towel. Replace ducting. time taken, 15 minutes max.
5) start engine and allow to warm up whilst feeling the top radiator hose. If the thermostat is open the hose will feel slightly warm quite quickly but will take a long time to get hot. If thermostat OK then hose will suddenly become hot only after the engine has been running for a while. Time taken, about 10 minutes.
6) switch off and locate O2 sensor on the exhaust manifold. Disconnect lead at junction on bulkhead and slip a 22mm open spanner over the flex and down to the sensor nut. Remove sensor and check the tip for soot or white build up. If caked, heat it with a plumbers butane burner until residue burns off. Allow to cool, replace and reconnect the flex... time taken 30 minutes.

Inside an hour to perform a full diagnostic check and possible remedy.:thumb:
 

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