Poor MPG

DennisTheMenace

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I have recently bought a 2004 C220 CDi estate auto, I have taken it into Steve at Avantgarde (top bloke!) and had a service etc done but i am still getting crap MPG?????

its driven steadily but doesn't even want to crack 30mpg! driving back from Martock to home (17miles) it managed 25mpg :( , Quite depressing really with what i have just spent.

Driving my FIL's over in South Africa i could get close to 50 mpg out of it, so with this one i am totally bemused...

work its had done so far:

Assyst A service
Air Filter
Fuel Filter
G/Box Oil/Oil filter etc replaced
new rear brake pads disc's etc as they were binding

STAR Diag was done and no faults found, and the quantity correction codes for the injectors were corrected by Steve as the previous owner had changed the injectors at some point and hadn't done this.

So, after all that, is there anymore suggestions as to what it may be causing my frankly horrific mpg??
 

brandwooddixon

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Certainly something seems up.
Does it have a DPF fitted?
Other than that I'd suggest talking to Steve.
There could also be a problem with the fuel consumption readout. Try a brim to brim test first and work out the average consumption manually.
 

Nidge

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Have you checked the thermostat? This is a common problem with BMW 5 series (my previous car) which means on short journeys the car is rarely warm enough to attain good mpg figures.
 
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DennisTheMenace

DennisTheMenace

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Hi nidge, the thermostat looks to have been changed recently. The temp gauge in the car sits above the 80c mark.

Brandwooddixon, it does have a DPF fitted, so far I have used quarter of a tank and it has done 80 miles :shock: that can't be right!

I will say at tickover when cold it is rather lumpy, seems happier when warm. Overall though loving the car, but as it is going to double as my works car I need better mpg's!
 
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Pathfinder

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Injectors. Maybe the nozzle spray pattern or dripping.
 

streaker

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Mine started returning this kind of mpg (25-29mpg), I disconnected the MAF and the mpg was much better (40ish mpg) eventually though it got stuck in limp mode, Steve(avantgarde)sorted it all out at very reasonable cost

For comparison mine has the DPF and I return
Around town 33mpg
Combined 40mpg
65mph motorway 49mpg
80mph motorway 42mpg

Steve has a C220 with DPF and gets similar mpg

Cheers
Adam
ps does it plume much Black smoke on acceleration?
 

wemorgan

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From my experience, automatics are not always economic on rural roads. All that accelerating, braking, plus little opportunity for being in top gear just adds up to lower than expected mpg. Like for like I'd imagine a VW Passat 2.0TDi manual would give ~40mpg.
 
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DennisTheMenace

DennisTheMenace

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Hi Adam, I get zero smoke from it, I'm going to give it a dose of diesel injector cleaner, plus the good old Italian tune up and see what happens :)
 

streaker

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If it's not blowing smoke and the Injector correction values are good, then you can probably look elsewhere for the problem, which is good news as the injectors are the expensive bit (I'm no expert) , Steve removed the internals from the forward CAT on mine (I think it was coked up)this improved the MPG no end ( didn't cost much either )
I asked about the smoke because mine blew thick clouds of it which I assumed was caused by over fuelling, when Steve sorted the MPG it still blew loads of smoke, I had 2 injectors changed which cured the smoke but didn't affect the mpg
I would contact Steve he will get it running sweetly

Best
Adam
 

Smacsor

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Mine started returning this kind of mpg (25-29mpg), I disconnected the MAF and the mpg was much better (40ish mpg) eventually though it got stuck in limp mode, Steve(avantgarde)sorted it all out at very reasonable cost

For comparison mine has the DPF and I return
Around town 33mpg
Combined 40mpg
65mph motorway 49mpg
80mph motorway 42mpg

Steve has a C220 with DPF and gets similar mpg

Pretty much what I get from my Blueefficiency C220. It certainly is a car of extremes where mpg is concerned which I also put down to the auto box. Mine can be as low as 25mpg driving around town but I can get 60mpg plus if I nurse it on a run.

Simon
 

MERC210

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RE MPG

My e320cdi v6 shows 31 mpg on a brim to brim test its 36.7 best way of checking
 
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DennisTheMenace

DennisTheMenace

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Hi Chaps, thanks for the comments, currently i am at half and tank and the car has covered 180 miles, as i managed to cut my foot deeply tonight i had to go to A&E in bridport for stitches, driving over the car was doing around 35mpg, on the way home that figure dropped by 10mpg??? could it be constantly trying to do a regen on the DPF?

also when cold its very uneven on the idle but soon goes when it warms up. Could this also be related? i will be giving Steve a shout Monday, but its really got me scratching my head as to what it could be.

Modern diesels, too complicated for there own good!
 

Pathfinder

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How did your foot get cut?
 
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DennisTheMenace

DennisTheMenace

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Glass, Dropped a bottle, it smashed, Bounced (kind of) then part of it lodged itself in the top of my foot... Not something i think i could repeat... TBH not that i would want to!
 
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DennisTheMenace

DennisTheMenace

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Drove down to Torquay at the weekend, sat at 70 on the cruise and all it could scrape together is 30mpg, my mondeo diesel would get close to 60 on the same run.
I have now done 320 miles on this tank and I have just under quarter of a tank left.


Love the car in every other respect but this MPG is just shockingly ****e.
 

Steve@Avantgarde

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I am being plagued by these at the moment with no consistent faults and fixes across anything and I thought I had this one sussed.

O/S/R brake was locked on and could barely turn it by hand and all the quantity correction codes hadnt been coded. Thought I had cracked it but clearly not!

I had another one doing this on Monday, this one would give poor econ around town about 25mpg and after much poking and proding I replaced a MAF. Customer rang me today to say its up at 35. Maybe this is the same case here.

Give me a call and i will take another look.
 
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DennisTheMenace

DennisTheMenace

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Hi Steve, Thanks for the chat this morning, Would pulling the plug on the MAF be worth a try and seeing if MPG figures increase?

Also would the DPF possibly be a bit bunged up due to the excessive fuel use? and then be consuming more fuel to keep doing more frequent regens???

Cars booked in for next Wednesday with Steve, hopefully its something stupid!
 
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DennisTheMenace

DennisTheMenace

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Right, it appears i have found the issue, It was the ****** MAF sensor...

Looking at components under the bonnet the previous owner had poor mpg so changed the MAF, thermostat, and a couple of injectors. but i think he may have got a cheapo one off the bay of fleas.....

Unplugged it tonight before driving to Bridport, idle was a damn sight smoother and mpg initally dropped to 32mpg but by the time we had driven the 5 miles was up to 37 :) by the time i got home it was at 41 Result!

Had to stare at a ginger engine light, but that was better than 25mpg!
 

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