c220cdi slow acceleration start

[bridgnorthboy]

Have a 2003 c class auto which is really beginning to annoy me! For the first 2 or 3 pull aways in the morning it feels like I have hardly any power at all. The accelerator then kicks in after a couple of seconds. Dealer has had car twice and early morning start with diagnostic attached showed no fault! It is still just the same now and is going back again on 11th April.
Anyone else had the same problem or can suggest what the problem is

 

[citroennut]

hi, have you tried switching off and then restarting? if it cures the problem i would look at air mass sensor but should have been diagnosed by garage
simon

 

[Uncle Benz]

Slow acceleration when cold

My ML270CDi has always been like this. I presumed it was normal. Has this only started recently for you?

 

[davebox]

Thread
Have a look at this, Im off to talk about changing the car with my dealer later today:-(

 

[jberks]

My 270 is a bit unenthusiastic first thing in the morning. I believe its to do with the engine power being turned down until you get a bit of heat into the oil. Within 1 min or so she's perkier and once warned up, back to rocket status, the whole process takes 5 mins or so but as it protects the engine I am happy and just don't push it.

You say its fine after a few mins without a switch off. If this is the case, its not safe mode, hence there are no faults to interrogate. I suspect things will improve as the weather does. Perhaps have the dealer check the temp sensors. Maybe they are a tad lazy. I suspect there is an override built in for safety so if you floor it, full power may return - hence the momentary delay, plus after a few secs, the turbo will be up to speed and assisting.

 

[Rory]

My 270 is a bit unenthusiastic first thing in the morning. I believe its to do with the engine power being turned down until you get a bit of heat into the oil. Within 1 min or so she's perkier and once warned up, back to rocket status, the whole process takes 5 mins or so but as it protects the engine I am happy and just don't push it.

I'd say my 18mth old C270 is just the same, too. I back it out of the drive, then put it into D and I sometime wonder if it's actually going to move at all. Then 200 yds away I have to stop at a T junction and it's similar. After that it seems OK. Interesting theory about the oil - wonder if that's correct?

bridgnorthboy - really sorry if this is a dumb question, but you're not driving it with the auto in C (or W) mode, are you?

 

[bridgnorthboy]

thanks for your help

Thank you all for your comments, I will pass them on when I take the car in for checking. Glad that I not alone with this problem, service manager has never heard of this problem!!!!
UNCLE BENZ..Only noticed the fault this winter but only got the car last june so it could be the colder weather. It acts the same in S or W mode!
RORY Tried S and W mode and the result appears to be the same!

Will come back after the car has been back to the garage.....

 

[Sule I. Karofi]

Hi all,

I just got my C-220 (1996) about a month ago, and it appears the cold starting is a normal thing with them, because after about 5min and a temperature increase to about 80 deg (I am driving it in a tropical weather. Africa) it stablizes and runs normally. I want to believe is normal!!

 

[tamrsoft]

I get a similar problem in my E220 CDi, it's acceleration from stop in the first 4-5 mins is not exactly at its peak (like having the selector option switched to 'W' instead of 'S') but after this its' back to normal. I wondered if it was the viscosity of the oil when cold slowing the turbo performance.

 

[robbi-wan]

This seems to be common feature across the CDI engines, mine too exhibits this behaviour at start up.
It has just occurred to me that a common denominator is the turbo.
Given that turbo's work of exhaust heat ( and there is v.little of this just after startup) maybe this is the cause of these symptoms and it is all completely normal?? Seems plausible to me.

rob
PS. I ruled out the MAS sensor by ragging it to 4000 rpm up to 4th gear

 

[PaulJS]

I to have found my E320 CDi to be a little sluggish from cold straight off the drive, also the first few gear changes are not as smooth as when its all warmed up. After a few mins i get full power back and all is well again.

 

[jberks]

Turbo's don't run on heat, rather exhaust flow, which is the same whatever the temp. Admittedly the tolerances possibly mean that the turbo is a little more efficient when red hot but I doubt it makes that much difference. I suspect its a mapping built into the ECU and based on the temp sensors, though how we prove this I don't know.