230k M111 CLK. Poor Fuel Consumption - very bad

tjs_riley

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Hi. I have a 2001 CLK 230k M111 Engine (owned since new) with about 100,000 miles on the clock. The cat, backbox muffler and muffler have all been changed because of wear (to original Merc parts except for the muffler which is now a Remus)

For the last 30-40,000 klicks, my fuel consumption has steadily gotten worse (and this in on a diet of Mobil 1 0W40 every 10,000 klicks and all recommended changes). I recently changed the MAF and O2 sensors as well as the one way valve to the supercharger as well as the low end breather hoses.

Still no joy. If anything the fuel consumption has gotten worse ~ 14l/100km and the low fuel light comes on at 355-360 km where when new, it would come on ~470-490 km mark (a full tank is 60 liters - the above figures are based on actual fuel consumption and not the trip computer).

On idling the computer puts the fuel consumption at ~20-26 l/100 km !

Upon starting in the morning (temp ~27 deg C), the average fuel consumption is ~17 km/100l before dropping down to ~14 after 30 km or so (and this is while feathering the accelerator)

I did a dyno last week out of curiosity , 154.4 bhp on the wheel ( which equates to 193 bhp on the flywheel ~ no degradation from original spec) and the fuel air lamda reading of 12.5 (which I'm told is a bit rich)

Does anyone have any other suggestions on what else I should be looking at ?

Thanks in advance
 
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tjs_riley

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Also changed the themostat on the radiator upon suggestion. Still no joy.
 


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