Y.Issa

I have my c250 cgi since the end of last year. I am suffering two problems during acceleration.
The first one is a delay of almost 1 second after depressing the accelerator suddenly. I visited the service center and they said this is normal, and a friend of mine who has a one year older c280 says he suffers the same and that he wants to sell the car because of this. Is this normal? is there something that can be done to avoid it?

The second one is if you depress the accelerator down to the end while the car is moving slowly the RPM exceeds the maximum and the engine stalls, and you have to remove you foot so that transmission takes place. This is more dangerous than the first problem and it is really frustrating.

Anyone who has a solution please shout out.

lithium332

Wow don't scare me, I have a C250 CGI due for delivery in July. The first problem sounds normal and I believe all if not most Mercedes have that 'issue'. Did you get the Sports Package? If so, I hear putting the car into "S" mode instead of "C" will noticeably improve throttle response.

Regarding your second problem, I don't think that's normal and sounds quite dangerous if it happens regularly. Continuously exceeding the red line causes permanent wear to the engine. Have you discussed the second problem with your service center?

Cerano

the first problem is not a problem per se.

that is called turbo lag. your turbocharger takes time to spool up with the exhaust gas. thats the diff between turbocharged vehicles and supercharged, for SC vehicles the delivery is instantaneous.
A C280 would be V6 and i dont think his lag is as apparent as yours as his is more of a tranny thing.
as for your second problem i havnt experienced it before

Y.Issa

I got the elegance, and I use the C or the S with the same response.
The second issue MB service center put the car on the computer and they said everything is normal, this happened to me four or five times. Other wise the car is a beautiful ride, and when you go on accelerating, you have power.

Y.Issa

As you said, the C280 has no turbo, and his lag is almost the same, but accelerating 0 to 100, his car is slightly better and smoother. The amazing thing is at high speed acceleration, the response of the 250 is much better, as far as I saw.

I think that Mercedes Benz electronics that has to do with transmission can have a great role in this. I do not think that the delay is mechanical. This is one thing that you never get in a BMW.

Carsy

When you are aware of the lag you learn to live with it & drive accordingly. I think it is the gearbox looking after itself & preventing any severe internal shocks under heavy acceleration.
It is not a problem with older, mature drivers, he he!!

Y.Issa

Though I like the joke, I used to drive a 230.4 year 1977. Mature enough I think. If this is the superior engineering for protection, from Mercedes benz, then it looks to me that BMW, Ferarri, Prosche, and many others who make cars with super performance are hasty and do not calculate things as accurate.

Learning to live with a problem does not remove the problem

tls1212

There is a solution the correct this problem is using the sprint booster to reduce the throttle respond

Y.Issa

Excuse my ignorance. What is a sprint booster? Where do you get it?
Is it a Mercedes Benz approved solution or will it void the warranty?

Thank you

Yasser

Cerano

go ebay

its a plug and play device that will increase throttle response.
not sure if it will help though

Carsy

Yasser,
Did you not test drive the car before you bought it? . I took the test vehicle home overnight & checked it out mechanically & test drove it under most conditions. I can live with the delay & do enjoy the car.

Y.Issa

No, I drove my friends 280 before I bought it, there was no 250 here then

kyacout

hey people i'm new here so, I also own a c250 and I really need help with something I posted a thread earlier but no one replied with a resonable answer so please help the thread is called c250 engine stalls.....

chokaay

Since this thread was bumped, and no one seemed to have "solved" OP's initial problem, I wonder if a TCU reset would be the answer he's looking for...

https://mbworld.org/forums/c-class-w...esponsive.html

I have no idea whether you can reset the TCU on a CGI like this though...

prhsaunderrs

C250 CGI
We purchased a C250 CGI last December and have had nothing but problems with it, Apart from the sluggish pickup !!! under statement the gearbox has now been replaced ,the front struts replaced ? the power steering just stoped one day ,tow in to dealer and repaired, now the battery keeps going flat !!! three time in on e week >? and the road side assist man said there was no fault with battery or charging ? must be the car management system.

A true lemon car if I have ever seen one ! don't buy one

waiszeto

I have no idea about the cgi model, but I drive a c250 4matic. My engine is v6 2.5 with 7 speed transmission. For your first question, down shift to the right gear at right speed.can definitely solve the first problem. For example, gear 1 can drive up to 45 km, gear to can up to 80, gear 3 = 120, gear 4 = 160. If you driving at gear 6, 60km, 2000 rpm (most likely will happen in c mode auto) , down shift to gear 2 manually, the rpm will jump up to 4000, then u can power pass plp easily. Also, if u kick down the gas panel all the way after you downshift, it will up shift for u automatically at 6300 rpm.

Kaewen

sprint booster....

SSJ

Maybe you have to reset the transmission system and drive it in S mode,there is clearly a different between c and S.
When you drive in c it starts at the 2nd gear and S will start at 1st gear.

My friend has a c180 CGI and I drove a couple times in it and driving in its S and probably hes gearbox learned hes style of driving which is aggresive,there was no lag at all

joesama

Hey guys,
The lag in acceleration with the C250 CGI is normal.
But once the gear is in place and the turbo kicks in, its amazing.

That 2nd thing is not normal. It should not be going above the red line and it never happened to mine.

Oh by way, its the C250 CGI with 4 Cylinder 1.8 engine right?

joe....

bhvrdr

There seems three major areas of lag in this vehicle that you may or may not be sensitive to depending on what you're used to driving before this car.

1. Turbo lag. This is the time it takes for the car to go from it's naturally aspirated power to the full power of the car at full boost. Peak boost is reached relatively low in the rev range but it is not instantaneous power like a naturally aspirated engine. To me, I barely notice the turbo lag because I came from several 1.8t and 2.0t turbo motors with turbo upgrades making the useable rev range between 5000rpm and 7000rpm (ala gt28rs upgrades on the Audi 1.8t). That is big time lag. Those that came from torquey NA V8 engines though, may be very sensitive to the turbo lag.

2. Throttle lag. The drive by wire system has a bit of lag. A members supposedly tested it under one condition and measured it at .2 of a second or so. Whatever the value, there will be lag there. Even at .2 of a second, that is definitely perceivable although some may be more sensitive to feeling it than others. With respect to the poster who said that driving in E mode versus S mode will make the vehicle start in 2nd gear versus 1st gear. This is false.

3. Transmission lag. This i notice significantly and is probably the most annoying to me. You'll notice this most when stomping the pedal to the floor and then doing the , "wait...wait...wait...downshift." Even if this engine was running only on its naturally aspirated 4 cylinders, the transmission should respond immediately to a sure footed stomp to the floor with quickness. It doesnt. "reset" the TCU all you want. The delay will remain. I'm hoping MB comes out with a TCU update for the c250. We'll see.

Ultimately none of these are probably deal breakers or we wouldnt have bought the car. I bought this car for luxury. It's not a sports car by any stretch. Perhaps i'll do a sprint booster to address #2 above if a performance software upgrade doesnt impact this enough. Otherwise, not much to be done.

With respect to you having a stall when going full throttle during cruising speed, this sounds most like an overboost or underboost fault condition. This is most likely to happen when cruising at approximately 2000rpm (high load rpm) and going full throttle. You'll get the highest peak boost at that time and if the actual boost is not in spec with requested boost you will go into a soft "limp mode". It will require service.

Cheers! Mike

Glyn M Ruck

Indeed. Turbo lag is turbo lag - only way around it is one small turbo & one large one.

All fly by wire Benz cars suffer throttle lag with the standard ECU flash. Sprint booster does not remove the lag. Only an ECU tune can do that.

Transmission lag comes with 722.9 territory. The AMG flash improves this at the expense of some smoothness and as it works in conjunction with the ECU tune that AMG uses - messing around with Star in developer mode is not a good idea.

Regarding which gear the car pulls away in I'm all ears as I might be out of date with latest software & I'm interested.

All Boxes with S & C pull away in 1st in S mode & 2nd in C or comfort mode (old winter mode on early 722 series 5 speeds)

From the 722.9 technical training manual:

S (Sport) first gear start
C (Comfort) or E (Economy) second gear start, earlier upshifts and later down shifts. Auto default to E on Blue Efficiency models.

Note: Transmission will start in first gear if any of the following apply.
1st gear manually selected.
3/4 to full throttle applied from stationery start.
Engine cold (catalytic converter warm up)

Now - to precis the following: Certain high torque diesel models will pull away in first gear in both modes to protect the torque converter.

Mike et al - Would appreciate your comment.

The OP's over revving problem is a fault.

EDIT - Mashing the throttle to the floor will create even more lag as the ECU battles to get mixture under control in my experience (non CGI models) Progressive throttle application will achieve the fastest start.

bhvrdr

Thank you very much for the information Mr. Ruck.

In truth you are probably right about the current programming starting out in 1st versus 2nd under part throttle application. My normal driving style in this car is at least 75% throttle application due to its relative lack of power so all I am every seeing is 1st gear takeoffs. Likewise, the upshifting in both modes is the same for me when the pedal is floored. And dont get me started on how the manumatic mode continues to shift for itself relative to throttle position/inputs instead of user selection Let me try out part throttle applications more and see the differences. Of course it begs the question to mercedes of why would you need a Sport mode if the Economy mode has the same functions when using more throttle inputs. I suppose this is so the car "feels" more sporty when driving very conservatively?

Cheers! Mike

Glyn M Ruck

Mike - I have just bought a 2009 CLK with the 7 speed. I wish Benz would do away with the learning side of the TCU & give us a few preset maps to switch to.

Don't get me going on that.

kevink2

Although I'm an "SB's ok" guy, it won't help a 1 sec delay from stop ( unless you have one on the same diesel). It may make the overrev problem worse.

Bad Idea, IMHO.

--------------------------------

OP,

For slow start, I suggest a little bit of left foot braking and reving the engine to about 1200 rpms or less just before the start. You just want to hear the turbo spool a bit, so very little throttle. It's a method you need to finess, so you don't spin tires or burn out the trans torque converter. You just want a better start, when needed. Too bad no ecu mod to add timing during a start like this.

The over-rev problem can simply be fixed by lifting off a bit before redline, to let it shift. Again it takes practice.

You can sit back and be anoyed, or just adjust your driving style and enjoy your ride.

Also, what xW-Y oil do you use? Thick oils made big lag difference in my old solid bearing turbo in my Saab (rip).

General Q: Does that turbo have solid bearings (vs ball bearing)? I suspect solid.

.

Glyn M Ruck

Just one comment - The AMG flash has always allowed overrev & hitting the limiter. The standard flash is not supposed to do this. Your driving advice is spot on.