ml270 cdi Loss of Power

[tony jr]

Hi

Can someone please help me ? My ml 270 cdi 2003 has just started to loose power (sound familiar!) – but not all of the time. When you drive off in the morning the car works fine if you put your foot down you can feel the car accelerate and hear the turbo kick in with the engine revving past 4000 rpm. However, after about 20 min when the car has warmed up it suddenly looses power feeling very sluggish not revving beyond 2500 rpm even with your foot to the floor (like going into limp home mode but without a warning light). This makes it slow to go uphill or overtaking when you need the power.

I have been looking at similar problems that people have reported and come to the conclusion that it might be a faulty MAF sensor or possibly the fuel filter. I have tried unplugging the MAF sensor but this does not appear to make any difference.

Can someone please advise if I’m on the right track and should I try cleaning the MAF sensor with isopropanol or just replace it? If this fails what should I do next?

Any advice would be very much-appreciated

Thanks

 

[Jopppop]

Hi, I had exactly the same problem with my 2003 270 CDI ML. My local independant garage used STAR diagnostics to confirm it was a faulty air mass sensor. It cost me £40 for the diagnostic test, £51.57 for a new air mass sensor, £65 labour. Plus VAT, total £180.06. When I picked it up, it drove like a new car, but still has a surge problem as if it's missing at 2500 RPM ? My advice is to pay to have it checked on STAR diagnostic equipment. Cheers, Graham.

 

[ABBY]

check fuel filter and prefilter.prefilters are usually ignored and once blocked it causes loss of performance.
good luck
Abby

 

[Druk]

Similar, although irregular, symptoms on 320CDi. STAR threw up a faulty inlet pressure sender.

 

[tony jr]

update

Update:

After crawling home last night I decided to try cleaning the MAF sensor. I removed the MAF sensor (Pierburg A6110940048) from it’s housing and soaked the end of it in isopropyl alcohol for a few minutes (this released some dirty oily grime from the sensor) then sprayed the sensor with electrical contract cleaner, before replacing back in the car. I then took the car for a quick test drive around the block. The result was amazing the car felt like new the acceleration was much better than I can remember.

This morning I took the car on a 30 mile trip the power, acceleration, turbo performance was great to start with then after about 25 miles the power dropped off feeling sluggish not revving beyond 2500 rpm again.

Any ideas what to try next? Do you think the MAF is faulty and needs a more thorough clean or replacing? Or do you think that the MAF is nothing to do with the problem? Could it be the CAT? How would I tell? Could anyone explain to me if it is the cat why the problem is not there all of the time and why it does not effect the tick over (when the cat blocked on my E-class the engine would stall at tick over)? Someone suggested changing the fuel filter and or fuel pre-filters – where are the pre-filters?

Thanks for all your help so far

 

[Adam230K]

replace MAF

 

[poisas]

in such cases most easy way to start solving the problem, is to perfom diagnostics and get codes read. Than its more accuracy to solve the problem witch in most cases is not only 1thing failure, usualy its combo of failures that causes sympthoms.

 

[tony jr]

update

Just picked up a new MAF sensor from my local MB dealer (£51 + VAT - good price). Will fit tonight and let you know how I get on.

 

[tony jr]

Problem Solved

I have just replaced the mass air flow sensor then taken the car on a 6 mile test drive. What a difference the new sensor made - never had so much power! Who would have thought a small sensor would make such a difference!

Thanks for all the useful advise

 

[Boulds]

Hi all,

Yesterday afternoon my ML lost its kick down mode and wouldnt rev higher than 3000rpm. Its the same today.

From reading this thread and others, it seems first port of call is MAF Sensor.

I have got one on order and will fit it myself. Can anyone offer some pointers to this process.

Cheers

Iain

 

[BlackC55]

http://www.mbclub.co.uk/forums/engine/144927-lack-power-cdi-what-do.html

 

[Fletch1971]

Ml 270 cdi no power

Hi all I've just bought my first ml and there's no warning lights on but it's got no pull in it very flat anyone have any idea's where to start please thanks

 

[Lyserman]

Try the post directly above yours.

 

[Eric Alex]

Whats up with this kind of cars and loss of power. Mine picks well in the morning but after a warm up i drive pretending to be a boss up hills because I don't want guys to know am struggling to climb up hill... Its an ml270 cdi 2005
What MAF and where is it located???


Sent from my iPhone using Tapatalk

 

[urfi77]

Hi Guys, My ML270 2004, drives prefect in town never felt no problem like loss of power of any thing else but since I bought it, On the long run specially if I am going uphill i feel like loss of power and rpm starts jumping it does not show no error on diagnostic, could it be MAF Sensor???

 

[219]

Hi

Can someone please help me ? My ml 270 cdi 2003 has just started to loose power (sound familiar!) – but not all of the time. When you drive off in the morning the car works fine if you put your foot down you can feel the car accelerate and hear the turbo kick in with the engine revving past 4000 rpm. However, after about 20 min when the car has warmed up it suddenly looses power feeling very sluggish not revving beyond 2500 rpm even with your foot to the floor (like going into limp home mode but without a warning light). This makes it slow to go uphill or overtaking when you need the power.

I have been looking at similar problems that people have reported and come to the conclusion that it might be a faulty MAF sensor or possibly the fuel filter. I have tried unplugging the MAF sensor but this does not appear to make any difference.

Can someone please advise if I’m on the right track and should I try cleaning the MAF sensor with isopropanol or just replace it? If this fails what should I do next?

Any advice would be very much-appreciated

Thanks

Swirl flaps or motor failure .

 

[Bobby Dazzler]

Hi Guys, My ML270 2004, drives prefect in town never felt no problem like loss of power of any thing else but since I bought it, On the long run specially if I am going uphill i feel like loss of power and rpm starts jumping it does not show no error on diagnostic, could it be MAF Sensor???

Welcome to MBClub.

The MAF could be the cause. For how much they cost (~£60), it's worth replacing the MAF anyway, but I would suggest sticking with a genuine item from your local Mercedes dealer parts counter.

I fitted one myself albeit years ago, and from memory it probably took 10-15 minutes plus getting tools out and tidying up after myself.