S320 CDI Turbo issues

[Odonnella1]

I'm sure a few people have seen my previous thread with regards to my S Class.

I've had 6 months of hell with it trying to source a problem with the engine when it gets between 1500-2000rpm, It starts hunting/knocking/ Waste gate surging.

I've had every specialist and chief MB tech look at this in my area and they all keep throwing parts on the car such as:

Air Filter
Auto Tensioners on drive belt
EGR Valve
Throttle Actuator
ECU flash after ECU Flash inc. Gearbox ECU.
Air Mass Sensor
Manifolds (exhaust and Inlet) dropped and cleaned, all good.
Exhaust and cat dropped and flow tested , all fine.
Turbo dropped and checked, all fine.
Regen on exhaust gases (burn off of soot)
DPF relplaced.

And still it is playing up, They now are saying that it could be the Electronic Actuator on the turbocharger.
What I want to know is, what symptoms occur when the actuators play up?? I've had no fault lights or fault codes and I'm struggling for what ot do.

I've done a hell of a lot of cash now and dont want to have the Actuator repaired or turbo replaced with out knowing that it will have a80% chance of fixing the car.

Thanks people!!

 

[BlackC55]

Have you had the spray patterns of the injectors tested?

 

[Odonnella1]

Hi Black C55, I actually rung you about 2 months ago about this very issue and you were the first person to suggest the possibility of the turbo actuator. I cant say I have had this tested but the have checked all the fuel pressures and pump etc.. and that all looked o.k, Do you feel it may not me the actuator then?

I'm completely miffed now and would hand back the keys if I could!!

 

[BlackC55]

TBH I don't know. With these types of problems it is very tricky to say what it could be.

 

[Riverstick]

Check your front pulley/vibration damper...it's an old favourite for these symptoms