Car won't rev beyond 2000 revs

[adamjobson]

Hi,

Whilst driving long distances in my s class w220 2002 320cdi, my revs seem to be limited to 2000. If I am stuck in traffic it is fine so if the revs are changing continually there is no problem, if I put my cruise control on after say 30 miles I can't rev beyond 2k. When I pull over and restart the engine a puff of black smoke and back to normal.

Any thoughts? Throttle position sensor?

Thanks
Adam.

 

[Dave Richardson]

Dirty /blocked EGR ?

 

[adamjobson]

Looks like a good place to start, looks like a fairly simply DIY job to clean/replace.

 

[Pitts Pilot]

Something is blocked or dirty!

Probably best to start at the beginning and work rearwards:

(Mass air flow) MAF sensor. Easy to clean with the CORRECT spray cleaner.

(Exhaust gas recycler) EGR. There are sprays you can buy to clean this 'in-situ', but a thorough job can only be done by removing it first.

(Diesel particulate filter) DPF. Your last restort. There are specialist companies that will clean them for you, and save the cost of a new one.

The 'fuel system'. When was the last time you put a fuel cleaner in the diesel tank as you filled up? Some folk say they are 'snake oil', others disagree. I think it can't hurt every 10K miles.
I use a 'professional' cleaner in my Volvo XC60 AR6000 Fuel Treatments | Archoil

As for the turbo being the problem - unlikely and not something you want to even think about at this early stage....

Cheers,
Robert

 

[Pitts Pilot]

Opps!

Actually the "Beginning" is of course the air filter. Easy to over look, and yet cheap to replace!

Robert

 

[Auto-mobile]

You can spray and clean as much as you want, get it on a diagnostic machine to read the faults, if a sensor has failed wd40 will not fix it.

 

[adamjobson]

Just had a full service so air filter is new but I will have a quick check just to be sure.
Never used any additives ever always thought they were a gimmick just had a new fuel filter fitted too.
If I get a diagnostic test done I can find out exactly what has gone but may be a good idea to check and clear the EGR as the car has done 130k so I imagine will be pretty dirty by now.

Any good places to get a diagnostic test done in the north east?

Thanks

 

[BlackC55]

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

 

[Dave Richardson]

All of the above pieces of advice are quite correct, however there's one small idea that has been missed & it'll take just a few minutes to check, ( I made there error once)

Assuming that your oil filter is at the top front n's of the engine, there's a short length of vacuum pipe near to the oil filter & it's very easy to pull it off when re fitting the oil filter to the engine block. Since reading that you car has just been serived this may well be the cause of your problem

Dave

 

[adamjobson]

Thanks Dave I will check that when I get a min.

Think I will get a diagnostic on it soon as I can next week some time.

Thanks

 

[Harrythedog]

Straithes garage in Dunston, top man is Phil

 

[adamjobson]

Straithes garage in Dunston, top man is Phil

Right next to me I live on the other side of the metro centre

Cheers.

 

[Harrythedog]

Right next to me I live on the other side of the metro centre

Cheers.

It's right behind the black & white pub, Tudor Rose I think

 

[BlackC55]

All of the above pieces of advice are quite correct, however there's one small idea that has been missed & it'll take just a few minutes to check, ( I made there error once) Assuming that your oil filter is at the top front n's of the engine, there's a short length of vacuum pipe near to the oil filter & it's very easy to pull it off when re fitting the oil filter to the engine block. Since reading that you car has just been serived this may well be the cause of your problem Dave

A 220 S has a different set up.

 

[Dave Richardson]

A 220 S has a different set up.

I don't pretend to have the same experience as you mate

It was a thought & a mistake easily made, does this mean that you've found a similar thing in the past.

D

 

[adamjobson]

Bit of an update on this.......
Had a diagnostic test done and it showed a few faults which were cleared, they said something about some swirl flaps being locked open.

All faults cleared and car drives perfect done around 500 miles with no reported problems, fingers crossed all sorted now but i will keep an eye on it.

Thanks

Adam

 

[adamjobson]

Sorry for the delay in updating this thread.

It was the inlet manifold valve, just cleaned out and good as new.

Thanks for all your help.

Adam.