E280 Sudden loss of power on kick down

[timtjohnson]

On two separate occasions in the last month my E280 CDI (V6) has hesitated and then lost power when I have kicked down asking for some rapid acceleration. On both occasions the engine was fairly cold. The car then went into limp mode BUT with no warning light on the dash.
After pulling over and restarting everything appeared normal, including rapid acceleration.

On the first occurrence I had the Mercedes dealer look at the stored fault codes. They replaced the lambda sensor that was giving continuous faulty readings. There was also a stored boost pressure sensor fault but they couldn't reproduce despite lengthy tests and they recommended leaving for now.

Does anyone have any thoughts on whether my symptoms could be a faulty boost pressure sensor or whether it's something more sinister such as inlet port shut off motor, or turbo unit. Should I leave this until it develops further and avoid kick down when engine isn't up to temperature? Could dirty air filters cause such symptoms?

Finally, is the boost pressure sensor an easy DIY job that might be worth doing?

 

[timtjohnson]

...another thought I've just had is that perhaps it could be a slight air leak into the fuel lines. The car won't start from cold unless I wait 2 or3 seconds for glow light to go out - which I don't think is normal (well it isn't in my C220 CDI)?

 

[BlackC55]

The only way you are going to know what caused the lack of power is to get it plugged into a Star. There can be many reasons for the fault.

 

[mobeyone]

I never boot mine when cold.

Could be one of two main culprits, turbo actuator (I think) or inlet port shut off motor but if you search the forum there a few threads now on this problem with the v6 cdi.

Get it diagnosed ASAP and maybe have the turbo lubed, I plan on doing this on a regular basis.

 

[timtjohnson]

Having read the forums, i think the inlet port shut off motor is the most likely cause. Anyone know how much this is likely to cost?