ML270 Sluggish

[a11ocx]

Hi
I've read with interest a number of posts on the subject of poor acceleration on the ML270 & a restricted top speed of 80 - 85mph. All seem to point towards the MAF. with this in mind i optimistically changed both the MAF & the air filter on my recently aquired 52 plate.

Unfortunatley no difference!

Car drives ok other than this any thoughts of what to try next

Regards
P

 

[JOB-BLACK-RAT]

Hello and welcome to the forum, Im unable to give you advice on your question but Im sure somebody on here can.

 

[kwakdonut]

You really need to get the car to a garage equipped with STAR Diagnostics.

It will be come a real expensive headache changing things in the 'hope' of curing your problem!

Where are you located? Someone on here may be able to recommend a local MB 'Indie' to you to go to.

Anyway, welcome to the forum!

 

[a11ocx]

Hi

thanks for that, I'm based in Hartlepool in the Northeast.

Anyone have an other ideas?

 

[kwakdonut]

Hmmm, don't know anyone over that side myself, am sure someone will!

Your car appears to be in what is commonly known as 'Limp Home Mode'. The ECU restricts the power to prevent any or any further possible 'damage' to the engine or, I think, gearbox.

A possible reason for this can be a blocked or non-functioning EGR valve. If you do a search on here, there are plenty of items about this

 

[a11ocx]

Hi

I've read a little about limp mode on the forum, would i be able to do 80mph in this mode?

 

[kwakdonut]

Just about! The ECU normally restricts the engine to 3000rpm or thereabouts. You may also find your acceleration is much slower than normal

When you turn off the engine and restart - does it drive ok for a while or is it slow from the beginning?

 

[a11ocx]

Yes, that would about sum it up.

Slow up hills, no noticable "kick down" either

 

[Gazz270]

whats the mileage?i would be looking at the egr and inlet manifold for it being gunged up.mine had 117k on it when i got it and they were both full of oily gunge,once cleaned out it was much better and so was mpg,ive just done this weekend my maf because fuel economy had gone down,just wait now a week to see if thats cured it,

Gareth

 

[a11ocx]

Mine has 115K on it.

Is it an easy job to dismantle & clean out? What can you clear them with?

Paul

 

[dokalj]

How do you dismantle the EGR and inlet manifold?

Regards

dokalj

 

[Gazz270]

egr is easy enough but the manifold is a bit more involved,leave a good day for the whole lot.just be methodical when dismantling and reassembly,probably a good idea to fit new manifold gaskets at the same time.

Gareth

 

[twosnowmen]

80mph seems fast for a limp-home mode, its normally around 30mph max.

 

[MB Tech boy]

theres a rod under the inlet manifold for the inlet port shut off motor to the flaps in the manifold. check this hasnt popped off as quite common, also check the flaps move freely on the manifold

also check your catalytic converter isnt blocked up as they have 2 the 1st one breaks up and blocks the flow of the second 1.

 

[a11ocx]

Hi all,

thanks for the suport so far. I've just taken the right hand side engine cover off to see how difficult the EGR looks to remove & noticed a split in the large diamiter rubber pipe thats attached to it. I unclipped the pipe & as predicted it seems to be quite badly gummed up.

I temp taped the pipe up & it could be my imagination but the car seems more responsive already!

Tomorrow I'll see if my merc dealer has a new pipe to replace it & at the same time remove the EGR to clean it.

Any do's or don'ts when removing, cleaning & refitting?

Also the large pipe (not sure what its called) should it have a seal around the the metal end where it fits into the EGR as seems slightly loose

Thanks again so far

Paul

 

[Gazz270]

youve probably found your biggest problem with the split pipe,if your going to strip the egr and manifold just keep everything in order when i did my manifold i took the motor that controls the swirl flaps off,scraped as much of the crud off that i could get to.Then put 2 dishwasher tablets inside it and put it in the dishwasher on the hotest setting,cleaned it up like new (wife not too happy though,but manifold looked mint).

Gareth

 

[jaymanek]

Your problem is the pipe... the split will cause the car to register a boost pressure issue...

 

[kwakdonut]

80mph seems fast for a limp-home mode, its normally around 30mph max.

Nope, the engine revs are limited so 80mph is still possible

 

[a11ocx]

Is this pipe classed as the intercooler pipe? & does it come with the metal flange on the end does anyone know

Paul

 

[BlackC55]

It is called a boost pipe and they come with the flange.