CLK 230 Kompressor misfire

[Cyprus]

Hello all !

I own a CLK 230 Kompressor and am having an annoying problem with an occassional misfire, and a general feeling of being slightly down on power.Acceleration does not appear to have the same 'zip' as it used to when using the kickdown to overtake and such.

As an example, on the local dual carriage way today I tried the kickdown to overtake (around 70mph), the gearbox changed down one gear but there was very little acceleration and it seemed reluctant to change back up a gear until I backed off the throttle slightly. The car then felt as if it was running on less than 4 cylinders and the throttle was very unresponsive. I turned off the dual carriageway and entered a 30mph/40mph zone but the engine still felt the same, i.e. as if it were running only on maybe 3 cylinders with little throttle responce. Brought the car to a stop but left the engine running and the engine sounded as if it was struggling to run on all 4.

Turned the engine off and left it alone for about 30 mins, came back and it started and ran ok, auto gearchange was fine (up and down) but the car still feels generally very slightly underpower, not much but enough to notice, acceleration still does not seem quite as 'instant' as it should. It seems as if this problem rears it's ugly head mainly when I 'give it a boot full' as it were.

Any advice or suggestions would be most welcome, before I start throwing a bucket full of money at it trying to find out what is wrong!!

Better add that it is a 1999 year CLK 230 Kompressor, with about 80k on the clock. (The 'old' style CLK).

Many thanks for any help.

Regards,Neil.

 

[jberks]

Step 1
clean or ideally change the MAS (Air mass sensor). Sounds like yours is on the way out. This is by far the most common cause of the problem. The 3 cylinder issue was probably the ECU shutting down. Switching off andon again normally cures this (until the next time), so no need for 30mins - 5 secs would do. Change the sensor and I suspect you'll have your old car back.

 

[television]

I have to agree wth Jberks it does sound like the MAF, could be worth a clean before you buy a new one, 80k on petrol hard to say if clean or replace.

Malcolm

 

[jimsinessex]

Try cleaning it first, easy job and might save you about £350.

Jim

 

[Cyprus]

Bingo!! Problem solved,many thanks for the replies folks, much appreciated!!

Took the MAS out first thing this morning, there was no physical dirt or muck on it, just an almost insignificant looking faint oily film covering it. Gave it a wash in some White Spirit with a soft brush to remove it all and blew it dry with an air-line set at a low psi. (I did have some Acetone which I toyed with the idea of using, but that stuff can do peculiar things to some plastics so thought it best not to push my luck and try that!).

Fitted the MAS back in, warmed the car up and took it for a drive. Hey-presto, general performance and acceleration is back to how it was, just the job, could not believe that such a simple 'problem' had been causing the lack of performance! To be honest, the faint oily film that had been covering it looked so trivial I thought it was impossible that it could affect the running of the car in such a way, I actually had visions of the supercharger or something being knackered....!

Again, thanks for the replies, you cured the problem. I have never used this forum before and your answers to my first posting certainly helped me out. The first round is on me then .... lol !!

Cheers, and all the best.

Neil.

 

[G MAN]

Glad you sorted it as this is a common problem that eventually affects us all.
Loads of good info on here http://forums.mercedesclub.org.uk/showthread.php?t=18298
http://forums.mercedesclub.org.uk/showthread.php?t=19428
http://forums.mercedesclub.org.uk/showthread.php?t=19430
The last one being my own frantic response but after a third opinion seems like it's only maf related & poss. some vacuum blocks etc as mentioned .I've yet to do any actual work/replacement valves/to find out where the root cause so living with it & keeping maf clean. Also search for <resetting gearbox>on here as that does seem to have some effect

 

[Cyprus]

Also search for <resetting gearbox>on here as that does seem to have some effect

Ok, thanks for that. I found the thread on resetting the gearbox,never heard of doing that before! What does resetting the 'box actually do? (Never done it before!).

Many thanks,regards, Neil.

 

[Cyprus]

Well, almost exactly a year ago since the MAF started playing up and it finally gave up the ghost a couple of weeks back, very sluggish performance, wouldn't change gear when it should, rubbish acceleration etc etc. Gave it a good clean again but that did no good. In truth general performance has been on the decline for a while.

So yesterday popped into my local EuroCarParts and grabbed me a new Bosch one for about £160 (don't know if that is a reasonable price or not, was just fed up with things to be honest). Fitting took all of about 5 mins, and am I happy with it now...? Definately, it is like driving a completely different car, hard to believe how much better it is now!!

So, if your MAF is on the way out and are thinking of changing it, DO IT!! (Just hope the Bosch one lasts!).

Oh, and by the way, now that I have fitted a new one, is there anything that needs 'resetting' or 'adjusting' or whatever, that could be affected by fitting the new MAF?

Thanks for your help people, it is this handy forum that led me to the cause of the problem in the first place. (Admittedly quite a while ago now ....!).

Neil.

 

[jamesmc]

Neil

I find this Forum a great source of information especially impressed with how helpful some of the members are.

It's also good that you added a follow up (a year on) concerning the MAS issues you've had as it will help me diagnose the problem should this start happening to my car which is of a similar age/mileage.

 

[Jan Badenhorst]

Hi I am from South Africa and have a Clk 230 Compressor coup. If u start the car it runs smoothly and revs up nice but soon it starts to misfire and jerk. I changed the plugs but stil the same. If u switch it of and start it up again it runs smoothly again en then starts jerking. I see if I plug out the air flow meter it runs better. What can the problem be with my car. Thanks in advance. Jan Badenhorst.

 

[LostKiwi]

Your MAF is failing.

 

[Jan Badenhorst]

Thanks allot

 

[Jan Badenhorst]

Hi all. I am still struggling with my Clk 230 Compressor. It starts up nice and revs up nice to but as soon as I start driving it goes ok on pulling away and suddenly starts sounding like its running on 2 or 3 cylinders. Something like a tractor. If I switch the car of an start it up again it runs smoothly again until I pull away then it does the same. What can it be. Please anyone that can point me to the problem. Thanks allot. Greetings from South Africa