Maf Maf Maf Ecu Ecu Ecu Confused.com

[johno2004]

HI, All

Posted earlier about lack of power from my CLK320 1997.

After browsing thhe forum for the last 3 hours ive got confused as to what could be wrong with my car.

When im driving at a normal pace the car runs fine apart from idle in drive it drops to about 500rpm but in neutral go's back to 750.

If im traveling about 40mph and kick down it seems to take a age to get to 70mph and if i hit 4000rpm it just judders and total power loss till i relieve the right foot.

Now when i bought this car i thought i was buying a super car and at moment my wifes Mini would blow me away.

HELP NEEDED !!!!!

The last owner of the car was a lady and she has had it for the last 7 years and has only covered about 40k and car has 55k now with all service history and old mot certs. Now after reading posts about car adapting to new driving habits could this be that she was driving like miss Daisy for last 7 years and now i am giving it a real drive its not coping to well with the adjustments as ive only had it 2 days and covered only 100 miles.

Have had a look at the MAF and the only markings i can see are PBF- GF- 30
under i can feel some other markings but can not see them. do you think this is the original ?

Any help sorting this out before the indie costs start to esculate would be very helpful.

Thanks

 

[television]

Hi John, this does sound like the MAF to me, wait a few hours for some other views

Cant tell from that number, but 40k would be original

 

[jamesmc]

John

I can imagine how you might be confused, but the symptoms you describe do seem to point towards the MAF being at fault. Unless anyone else comes up with a plausible reason for you to think otherwise I would go down the MAF cleaning/replacement route as the first line of attack. If you notice no improvement after the clean/swap then the problem will need to be revisited by more knowledgeable members.

If you do replace it I would suggest you do so with a Bosch part as that will save on costs. Do a search on 'MAF Bosch' and that should give you what you need on that.

I have a CLK230K (W208 - 1999) which did suffer from the crank case breather nozzle blockage problem. Not sure if your unit has a similar breather system but you might want to read about that and see what may have cause your MAF to start failing if indeed that is the problem. Oil on the MAF will kill it eventually.

Sometimes the tick over on my car is as you describe.. The car does not suffer from power loss (not that I have noticed anyway) but, based on the tick over symptom alone, the next thing I will be looking at is the MAF because I am sure it will have suffered from oil mist prior to me sorting out the engine crankcase breather system. One job at a time I guess.


Also there is a thread here somewhere about how to clean a MAF... might be worth checking that out too before you splash out on a new sensor.

 

[television]

You can always unplug the MAF to see if it runs better though it may be lumpy

 

[jibcl500]

If the MAF is faulty, unplug the MAF with the engine running and if it is duff the engine will stall. If the MAF is ok the engine will keep running.

jib

 

[kth286]

johno

If your car will not go over 4000 whilst driving then it has gone into limphome mode and you need to get the diagnostic trouble codes read.

Either main dealer or specialist Merc independent, but make sure they have the "star" facility first.

 

[johno2004]

Thanks for the comments guys will try that way first and see how it goes,,Did unplug maf while engine running and first time engine died straight away tried again and it surged then went back to normal idle so not quite sure about them results.

Will dismantal it tom and give it a clean, what is recomended the only thig i have at hand is carb cleaner.but i would emagine that a alchohol bases cleaner would be more suitable ?

Thanks again for your help will keep you informed with progress

 

[C220GJS]

Isopropyl Alcohol Spray, available from Maplins/Radio Shack.

 

[television]

If you unplug it,take it for a drive and see if it drives better and over 4k revs

you will not tell much at ldle

 

[johno2004]

Just un plugged MAF and whosh straight over 4k revs but bit of flat spot on pull away but 100% better.

Car is booked in to indie Tues for a B Service and new plugs ( £200 is that a fair price for plug replacement fitted ) Shall i wait for his dianostic results before i change maf as i can change that myself.

Thanks again for your help

Does it cause any probs driving with maf unplugged ?

 

[television]

Just un plugged MAF and whosh straight over 4k revs but bit of flat spot on pull away but 100% better.

Car is booked in to indie Tues for a B Service and new plugs ( £200 is that a fair price for plug replacement fitted ) Shall i wait for his dianostic results before i change maf as i can change that myself.

Thanks again for your help

Does it cause any probs driving with maf unplugged ?

Nope, none at all, the mixture will be a little out, but that has proved the point it is the MAF, dont buy one from Ebay, try GSF or Euro and Bosch

 

[johno2004]

thanks will look for local bosch stockists think there is about 5 or so in Leicester