Poor Fuel Economy, E280 W124

[rathbane4]

Just purchased my first MB, a late 1994, W124 E280 Automatic Saloon. The vehicle appears in very good condition all round. The mileage on the clock is 112K with the 108K service being completed in July 2003.

I have had the vehicle maintained by a local MB trained independent mechanic. A new Lambda sensor has been fitted, as the existing one had been damaged, subsequent emissions test checked out fine. Plugs, Air Filter and leads are in good order, however, the fuel economy is very poor. On the 'Urban Cycle', at a sedate pace, I am getting between 12/15 miles per gallon.

The vehicles performance is good, idle speed is c550 revs, everything appears in order except the high rate of fuel consumption! Any advice, tips or suggestions would be most welcome.

 

[Aletank]

On my 1999 2 Litre Auto, 60k miles I get about 22mpg around town which is what I mostly do.
From a 2.8 litre I'd expect maybe 17mpg, Your mpg maybe a little low but i wouldn't expect much more from short journeys, around town with a cold engine to be honest.

 

[Spike]

I would say that is too high a consumption. I'd expect to get around 22-23mpg.

If your cars just been serviced and MOT'd and the CO readings etc were ok, then I suggest that you may have binding brakes, low tyre presssures and/or seriously misaligned wheels.

Check your airfilter though... it might also add to the overall problem.

It could of course be your odometer reading incorrectly :wink:

 

[DougE280]

I get 23 to 25 commuting and a best of 27.4 on a run to Brighton. A bit less if the A/C is working. I've had my Mercedes for nearly three years and never got under 20 in all that time.
One thought. Are your wheels and tyres standard?
If the rolling circumference is greater than standard then the car will be travelling farther (and faster) than the odometer (and speedometer) thinks! This together with possible greater rolling resistance could be causing you to clock totally unrealistic figures.
Why not do a test following a friend at a predetermined speed, comparing miles covered when you've finished.
If I'm wrong and you really are doing so few MPG, then sorry, I've no mechanical knowledge to help. Believe me, You've got a fantastic car (a bit expensive to maintain maybe) but think what you're saving in depreciation - and do you really want to drive a Ford or a Nissan.
Good Luck,
Doug

 

[Aletank]

'Urban Cycle', at a sedate pace, I am getting between 12/15 miles per gallon.

I get 23 to 25 commuting and a best of 27.4

If your journeys are mostly less than say 4 miles this will reduce considerably. I'd say 15mpg for this type of journey is possibly right - 12 mpg is low though.

I've just looked on the Mercedes web site and for a NEW E240 which has a 2.6 engine the fuel consumption for CITY is 19.1 mpg

When you say "Urban Cycle" what do you mean by this ?

 

[DougE280]

I must say that my daily commute is about 30 miles each way, 25 miles slowish motorway (M1/M25) and the rest is urban roads. My car is never used for short journeys - hence the low to mid 20's maybe!
Doug

 

[rathbane4]

Many thanks for your feedback. The only item that has not been checked out of the suggestions made so far is the wheel size. The car now has 16" CLK alloys fitted, not the 15" 8 hole alloys when new. Could the non std wheel and tyre size make such a difference to the MPG?

Regards,

rathbane4

 

[jberks]

Hi,
I've always found MPG to be very subjective. My 2000 E240 shows (on the computer) 22mpg on a 5 mile trip going to work (downhill), 13mpg on the way back (uphill and stop-start) and 35mpg on a run - 80mph on cruise. Its a heavy auto so stop/start will make a massive difference.