loss of power when cold c180

[higginjo]

last week i went out in the evening after the car had been stood as i pulled out into a main road the car was reluctant to pull away it would not change gear (its an auto) and lacked power, revs would not increase, after a few minutes it was ok and then ran normally i have had gear box checked out by transmission specialist and gearbox not the problem he suggested it could be the mass air sensor i have read the variuos threads on this and wondered if anybody else has had similar problems. I dont understand why after a few minutes it should run normally and then is fine for rest of day problem only occurrs when car has been left overnight and then quickly dissappears us the mas more susceptible to being faulty when cold i have read the thread on taking mas off and cleaning it that might be an option but am at the moment a little reluctant to purchase a new one as fault might lie elsewhere. Th plugs and air filter have been changed recently so i doubt the problem lies in that area, anybody any ideas i live near manchester so does anybody know of a merc specialist who might be able to diagnose problem without ripping me off!

 

[len_merclover]

Hi I had this problem and changed the MAS (mass air sensor) about £140 for bosch. Or I was advised also that It could have been the pressure sensor for turbo. hope this helps
len

 

[bob123]

I have read somewhere that my w210 is meant to stay in gear longer when cold, to enable the cat to reach nwt quicker to avoid damage.
perhaps this is the diagnosis ??
i am sure one of the seniors will be about soon to help more
bob

 

[bob123]

oops i cant spell lol

 

[David Nock]

The perceived wisdom on this forum has been that the merc electronics holds the power output down when the car is cold, in order to avoid unnecessary wear and tear on the cat and on other moving parts.
Our CLK 270 CDI certainly does the same thing, you'd think it was a 1 litre for a few minutes and gear changes are slow, then all is well and off we go. Also setting off after a few hours standing doesn't slow it down - just that 1st start in the morning.

 

[higginjo]

Hi Dave appreciate the quick response i have had the car over two years and this power reduction has only just developed so i have to assume there is a fault somewhere

 

[jibcl500]

Air flow meter, unplug it with the engine on tick over if its failed the engine will stall, if it doesnt then the meter is ok.

jib

 

[horgantrevor]

Air flow meter, unplug it with the engine on tick over if its failed the engine will stall, if it doesnt then the meter is ok.

jib

ide say give it a try mabe be a quick way to get an answer

 

[higginjo]

mass airflow meter

H i Trevor did as you advised engine continued running but not sure what this proves because if it is disconnected surely it cannot have any effect, therefore if its good or bad how does disconnecting it indicate its faulty or not.

Cheers
John