Poor acceleration and poor mpg

[Eltel1079]

Hi all, this is my first post so please forgive me if I do something wrong

I have recently bought a 2007 W203 Coupe C220 cdi 5 speed auto. No DPF.

Having had numerous turbo diesels from Vw, Ford, BMW etc this one seems to be lacking in performance and mpg.

I have done a lot of google searching and if you MB enthusiasts can’t advise anything then I’m going to sell it as I’m out of ideas

Basically it runs faultlessly, it’s smooth, comfortable and quiet.
The auto box changes smoothly and there are no hesitations or engine management lights.
The power is delivered in a very linear way but possibly too linear.

If you floor the accelerator the power builds nicely but with no real intensity, I can hear the turbo spooling but nothing really comes of it.
It reminds me of a hybrid Toyota Prius were the engine revs well but you don’t get much in the way of torque to throw you down the road.

If you go to overtake or to accelerate quickly from a roundabout I find it really lacking, a lot of normal family cars seem to be pulling away without trying and I have to wait until the speeds get higher than them to catch them.

There is no smoke at all and it revs to the red line in sport mode.

I am also seeing my real Mpg at around 34/35mpg which is me really nursing the throttle keeping to 55mph.

If I get near 65mph the mpg drops considerably.

The 34mpg is based on 3 tanks using 40L of diesel to 310 miles worked out manually. The dash says it’s done 37 ish mpg.

My same journey of 27 miles all on A roads with no stop start would see my Audi 1.9tdi 130hp return 46mpg driven a lot harder than this and at around 65/70mph.

So far I have done the following:

Tyres all good and correct pressure.
No brakes binding
New fuel filter
New air filter
New Maf sensor
Loads of fuel cleaner and turbo cleaner via the tank.
Removed 2nd cat which helped slightly.
Got the car remapped from 150hp to 180hp to see a small difference in power but not like the same remap on my 105hp Golf Tdi.

The egr was deleted at Remap and is in the closed position as I removed it to check.
I have a Bluetooth code reader that shows no faults present or stored and it shows the turbo boosts to 15-20psi.
There is no wooshing noise or associated air leak noise.

Overall I find the acceleration too lazy and the turbo doesn’t really come in with a bang.

My Golf 105hp with 190k is mapped to 130hp and pulls far better, the turbo kicks you back in the seat and it actually accelerates between the same fixed points to a higher speed than the 180hp Mercedes.

If you never had to overtake or accelerate quickly you wouldn’t notice but sadly for 34mpg I want a lot more power than it’s currently offering.

My next plan is to remove the 1st cat but if that doesn’t cure it, shes going.

Any help or suggestions would be greatly appreciated and I thank you in advance for any help you can offer.
I love the handling and drive but can’t justify driving softly at 50ish mph to only see 34mpg

 

[Eltel1079]

Forgot to say it also had a new thermostat and housing as when I bought it she was sitting around 50degrees.

Thermostat cured that and she runs at a steady 85/90 now

 

[geraldrobins]

The official figures for mpg and emissions are higher for your merc so expect poorer consumption.

 

[Eltel1079]

So I should expect a car with 55nm more torque (now 110nm more after remap) and 20 Bhp more (now 50 more after remap) to have about 3/4 the power of the less powerful previous Audi or current Golf?

I could live with the consumption if it actually went like I’d expect a German turbo diesel to go.


My 1.6 diesel Hyundai Tuscan with around 110bhp has more kick when it accelerates.

Must be a poorly designed engine for a 2.1/2.2 to be so sluggish.

 

[Deletedmember130310]

So I should expect a car with 55nm more torque (now 110nm more after remap) and 20 Bhp more (now 50 more after remap) to have about 3/4 the power of the less powerful previous Audi or current Golf?

I don't understand how 190 bhp is 3/4 of 130 bhp????

Don't forget your MB will weigh substantially more than your other cars

 

[Eltel1079]

The Merc weighs 45kg more than the Audi. That’s less than the weight of one of my young children.

So do you guys feel these engines are quite tame compared to other comparible vehicles such as the mondeo’s, Golfs, A4 diesels etc?

I thought there was something up with mine

 

[grober]

When the car was remapped was the power increase measured on a rolling road. Only reason I ask would be transmission losses- which seems unlikely on the face of it - unless maybe there's an engine /transmission mismatch e.g. the transmission is changing up too quickly to realise full engine power for example if you have a faulty economy/ sport etc transmission mode switch-- that sort of thing??

 

[Peter103]

Parker's list the c220 CDI at 143/147 bhp, 0/60 mph 10/10.2 secs, 40/47 mpg, so its not very quick, though your mpg could be better. I would have thought 180 bhp would have improved these figures. .

 

[kid-jensen]

You're chasing your tail unless you establish some base figures..

What 0-60 did Autocar get? If you could get within a second or so (before it was remapped) there's probably nothing wrong with the power. Don't expect to match it, because the Autocar testers are really brutal (as they should be) and will treat a test car like they didn't have to pay when they break it - which they don't. Owners tend to have repair costs in mind when they do dragster-starts...

If it's slower, you really should have found out why before you remapped it. I realise this advice is not exactly helpful.

What 0-60 do you get now?

If you've convinced yourself that the car is slow, you will be driving it harder all the time, probably without realising it. That would explain the higher fuel consumption...

That extra BHP from the remap has gotta come from somewhere, and that somewhere is your fuel!

 

[Eltel1079]

It wasn’t rolling roaded, just remapped.
This is the 3rd car I had mapped with the same guy and the other 2 were like night and day from standard to the mapped version.

It sounds like it’s just a characteristic of the car then.
The autobox doesn’t help and I probably compare the gear shifting speed to the xdrive bmw auto’s I drive in work.

Oh well, I’ll have to put up with it and decide on whether to keep or upgrade then.

 

[Eltel1079]

Does this engine have these manifold flaps that can get stuck or break?

 

[Riva811]

when did you last service the car?
Good idea to get sports filters for your car after the remap

 

[AntMB]

Mpg sounds about right. It's not a very powerful engine, so it's probably running as it should be.

 

[anderoo]

I have a 2006 C350 coupe, and for comparison my average mpg over the last many thousands of miles is 28. On any decent run I always get into the 30s though (e.g. I went from Oxford to Watford and back yesterday and averaged just over 36). So it does seem like 35ish from a 220 diesel is low, although I don't know whether it is or not in reality.

 

[Numair Aidroos]

I have a 2006 C350 coupe, and for comparison my average mpg over the last many thousands of miles is 28. On any decent run I always get into the 30s though (e.g. I went from Oxford to Watford and back yesterday and averaged just over 36). So it does seem like 35ish from a 220 diesel is low, although I don't know whether it is or not in reality.

Imperial mpg?