PLEASE HELP!! ml 270 loss of power going up hill and overtaking

[sheebamerc]

hi
Can someone please help me . My ml 270 cdi 2001 have all of a sudden lost its power. This happens mostly when i try to go uphill or overtake only. i have to put my accelarator right to the flloor and even then its sluggish. on flat smooth road surfaces there is ok pickup and some good power. but i have to keep at a certain speed. the turbo sounds ok . no heavy smoke . i have been researching and people have said it could be the MAF sensor . so thnking of replacing this as it has not been replaced before. any other suggestions what i can change . i really hope this is not serious like its the turbo going or something . im counting this out as there is no signs of this yet.

can some please also advise what is the boost pressure sensor has some affect to this and does it exist on the ML270 and where it is it in the car. Im in the uk.

any advise would be very much appreciated :lol:

thanks

 

[television]

This should just be the MAF,,sometimes you can just unplug it and the power comes back, and you could try that.

Its 14 in the link

http://www.detali.ru/cat/oem_mb2.as...GM=716.644&CT=M&cat=21T&SID=09&SGR=015&SGN=01

and around £47 from bosch

 

[sheebamerc]

Hi
thanks. I was going to replace this. do you think if this is the problem . my local mechanic mentioned replacing the air boost pressure sensor. where is this and does this exist in the ml 270. is it worth replacing this as well.

 

[television]

Hi
thanks. I was going to replace this. do you think if this is the problem . my local mechanic mentioned replacing the air boost pressure sensor. where is this and does this exist in the ml 270. is it worth replacing this as well.

Do the MAF first,,it sounds like the MAF to me

 

[sheebamerc]

ok thanks i will try this. just praying its this.

 

[television]

ok thanks i will try this. just praying its this.

If it responds well when unplugged then you have the answer, the car may be lousy at idle, but ignore that

 

[sheebamerc]

hi again

do i drive with it unplugged then

thanks

 

[television]

hi again

do i drive with it unplugged then

thanks

Yes try it sometimes it just proves the point

 

[sheebamerc]

ok i will try this when i come back from work. What signs do i look for Malcolm. what will i notice as the difference? . do you know?.

thank you for advisiing me so far. i appreciate it

 

[television]

Not all cars run well with the MAF disconnected, but some do and when they do respond by unplugging full power is returned, that is what you have to look for

 

[sheebamerc]

Maf

Hi
run the car today with the MAF disconnected . no change at all. disconnecting the MAF did not make the slightest difference to the symtoms pf poor power . does this mean the MAF is gone ???

 

[sheebamerc]

Hi
run the car with the MAF disconnected . no change at all. disconnecting the MAF did not make the slightest difference to the symtoms . does this mean the MAF is gone ???

 

[television]

With a break out box the voltages could be checked on the MAF and its not possible to tell without.

I do not like to say buy a new one just in case

 

[sheebamerc]

Malcolm

yes i have no option i think . the MAF seems to be doing nothing , as taking it out has not done anything either the cars lag is still the same . i think i will have to get new MAF and put this on. i rang my local merc dealer and they said they got one in stock for £52.00 + vat . so i was going to go for this . as its at least from the Mercedes.maybe its Bosch
shall i go for this? . my option is to try this first and see what happens i guess . as its the most likely problem. if its not this i think ill go for the fual filter and then the CAT .
someone on here mentioned a pressure boost sensor but i cant seem to find out what this is. do you know ??

anyway thanks Malcolm . i will keep everyone posted how things develop

 

[television]

We have had two post of this nature, where the MAF is doing nothing, and I have never seen this before, thats not a bad price to try at, sadly diesels are not my best point, maybe some more answers in the morning

 

[kebo57]

Hi sounds like the MAF to me, if it was mine I would all ready now this as I carry a spare maf & crank position sensor in the motor
as for fuel filter & CAT I would be doubtfully those would cause your problem, pressure boost sensor you have two of these they look the same but with different part No's, one down the front of side near a black plastic ball the other near the end of the throttle cable near side back you can swap them round might show something.

PS you will probably get other answers now to contradict what I have said remember if you take this to MB dealers they are going to pull you pants down with this, where are you located as you could just try my spare maf

Kevin

 

[muller1]

Loss of power

My ML 270 lost a bit of power last week and for a split second blew out a bit of smoke which I saw in the mirror as I was overtaking a tractor.
The car then seemed to return to normal MOST OF THE TIME.
I had it checked out at Diack Autos of Inverurie and there was a fault code of the EGR valve. This casn cause power loss as happened with my Ford Mondeo.
I am having a new EGR valve fitted next week, so this is something worth bearing in mind also.

Mike

 

[Mark A]

I would still start with the MAF, when the MAF on the wife's ML failed I disconnected it and, like you, it didn't make any difference. When I changed it - what a difference. It's a lot cheaper to try than replacing an EGR valve, last time I priced one up was over £100 + VAT from MB.

 

[kebo57]

I had it checked out at Diack Autos of Inverurie and there was a fault code of the EGR valve. I am having a new EGR valve fitted next week, so this is something worth bearing in mind also.
Mike

Hi I'm just wondering how they can obtain a fault code from a mechanically operated EGR valve, maybe from the lambda sensor. my ML has 208k miles same egr as far as I know.
I tested the operation of it myself as I was driving the car and it was working OK

Kevin

 

[muller1]

Hi I'm just wondering how they can obtain a fault code from a mechanically operated EGR valve, maybe from the lambda sensor. my ML has 208k miles same egr as far as I know.
I tested the operation of it myself as I was driving the car and it was working OK

Kevin

I do not know the secrets of fault codes but my previous Ford Mondeo was only 4 months old and the engine lost a lot of power.
The Ford garage checked it out and it was the EGR valve. The car had only done about three thousand miles and it failed.
The valves are mass produced and do not have a pre determined life span when they go they go.
Some will go on for ever and others will have a short life span.
Some people never have punctures and others have everyones share.
I can only assume that sensors can work out what has happened with the system and arrive at a conclusion be it right or wrong I will not try and double think the star computer system.
Like most other owners I can only go by what the computer says and hope it is right.
Thursday will tell as thast is when the new valve is being fitted.

Mike