lack of power

[John Kerr]

W203 220 CDI will only rev to about 3k.Have renewed the obvious things.MAS,BPCV,BPS,as far as I can tell the vacuum system is ok,the EGR valve ok.Has anyone had a cat blocked,if so what are the symptoms.Has anyone had inlet manifold problems ie the flaps breaking and if so what happens.I know the linkage works as the last diagnostics we could make it work with Star.The only faults were a stored fault "Boost pressure low".

Some one out there must have had a similer problem.I would be very happy to hear about it.
Many thanks in advance. John

 

[Dieselman]

The limp home mode has been activated by the boost being low.
Check the boost controller and the actual boost pressure. Check all intake ducting and intercooler for leaks under pressure.

 

[John Kerr]

Many thanks for the reply Dieselman.I have fitted a new Boost control valve no improvement,have had the intercooler off no leaks there.Do you know what happens when the flaps in the inlet manifold break off.I know the linkage is ok because we made it work with the diagnostics.Also what would happen if the cat was starting to fail.
Cheers John

 

[BlackC55]

It is possible to drive it without the cats on. Its not that noisey at all. Just remove the pre-cat and leave the other connected to the exhaust and take it for a run.

You may find a loss of power if the cats are blocked.

 

[John Kerr]

Thanks for that BlackC55. If I removed the pre cat I would have to make up a replacement pipe.Have you done this yourself ?.I was thinking about just removing the insides of them both.Any one any ideas what would happen noise wise.

 

[Dieselman]

Just drill into the downpipe and attach a pressure guage. This will soon show a blockage. Also usually with a blockage there is more black smoke as the engine has to work harder.

 

[BlackC55]

I ment remove it for testing. If the car has full power when driven without the precat fitted you know its the problem.

 

[BAABU]

W203 220 CDI will only rev to about 3k.Have renewed the obvious things.MAS,BPCV,BPS,as far as I can tell the vacuum system is ok,the EGR valve ok.Has anyone had a cat blocked,if so what are the symptoms.Has anyone had inlet manifold problems ie the flaps breaking and if so what happens.I know the linkage works as the last diagnostics we could make it work with Star.The only faults were a stored fault "Boost pressure low".

Some one out there must have had a similer problem.I would be very happy to hear about it.
Many thanks in advance. John

John I've suffered from the same problem on my W211 E220 CDi for 18 months now and I have replaced the Turbo, MAF and a Charge Pressure Sensor. To date the problem still exists. The STAR test (after being cleared) still reads "Boost Pressure Too Low".

I have no idea what I should do next and my specialist trained Mercedes mechanics don't either. They are just stabbing in the dark with wild guesses like "IT COULD BE ..." and come up with Turbo or EGR Valve.

Does anyone really know what I should be looking out for other than what has already been mentioned.

The car has done 136K miles now.

Thanks.

 

[tuikku]

.
Look, what dieselman says.
Do you know, what really is the actual boost pressure ?
You must measure it.
It must rise little over 1,3bar level.
Program asks 1,35bar max, but you get "full" power after 1,3bar.

If boost level rises enough, MAP, wires, or ecu broken.
If boost doesn´t rise, something leaks, or is blocked, or something in turbo system.

 

[yamin05]

my car will not go over 40pmh

hi i have cclass w203 cdi 2.2 2004 facelift last night when i was coming home i was doing 70mph and when i slowed down i couldnt got no more the 40 mph with the gas right down still will not go over 40mph

can anyone tel me what that can be

ut once it said add 1L OIL on my next petrol ful up but when i went to full up it said engin oil ok so inever added any oil

could it be enigin oil [ say oil ok on the screen