Originally Posted by
black_jack
All Mk3 Mondeo ST-TDCIs (2.2s) have vnts/ variable-vane turbos, controlled either by an electronic or pneumatic actuator, euro3 or euro4 emmision compliant
Cleaning de-coking the turbo on the car (foam cleaner "stuff" etc) often does not work, and a stripdown (turbo cartrige/ exhaust manifold ) may be nessesary the vnt mech is built into the one-piece exhaust manifold
the ST-TDCI does not have a wastegate, the vnt is used to control boost (by the ECU via the actuator) if the vnt siezes or does not function properly it may mean the engine boosts too little or too much/ is set for low or high boost/revs
Fair enough.
Sounds like cosmatt maybe on the right path by checking the actuator out first.
I changed a vnt on my merc Cdi and all it appeared to be was a normal turbo with a block plugged on the side which was calibrated to control the boost (i think),otherwise it looked identical to a normal turbo.
Hope it gets sorted fella.