Sudden poor mpg c220 diesel estate

streaker

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C220 Estate 2004 2.2 Diesel
Hello Forum

My first post and my first mercedes

I bought my car 4 weeks ago, Facelift c220 diesel auto estate full MB service history, and so far very happy, although there are a few things that need sorting but its done 99k.
It has been returning about 42 mpg combined, I commute from Somerset to Liverpool weekly and then its short (5 miles) to and from work,
However on the trip home on friday night I struggled to get 25 mpg, speed made very little difference 50 to 90 mph only 2 or 3 mpg difference according to the computer, filling up today confirmed i used £48 of diesel to do 195 miles.

Today I serviced the car replacing all the filters and the thermostat ( it was taking 10 - 15 miles to reach 80c) but no improvement in mpg, until i disconnected the MAF immediately the mpg went back up to low 40's (10 miles of A and B roads)

when I bought the car the dealer ( not mercedes ) told me the DPF had been deleted from the map and the internals had been removed, I've no reason to doubt this as i believe the remap has also increased the power over the other c220's i test drove

The car has been producing a lot of black smoke on acceleration, and on kick down its embarrassing but it pulls like a train so i thought the smoke was a result of the remap, now the MAF is disconnected the powers slightly down but the black smoke has virtually gone.

So I guess I'm going to need a new MAF ?, but my real question is, am I ok to keep the MAF disconnected until I fit the new MAF ?

Many Thanks for any advice you can give

Adam
 

grober

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W204 C200cdi estate
When you disconnect the MAF the engine ECU defaults to a "one size fits all" map which ignores several sensors and this is possibly different to the " remap" which would explain the change in power/ fuelling. Won't do any harm but I would resist the temptation to "cane it" until you get the new MAF fitted.
 
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S

streaker

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C220 Estate 2004 2.2 Diesel
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Thanks for the responses guys

Yes I will be ordering a Bosch MAF today, now just got to figure out how to get the heating to work and the rear wiper and ill be a happy motorist
 


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