Discussion
Would a faulty boost solonoid (or control signal in/from the ecu) do this?
If it were jammed open then that would limit the boost.
How to test....
Maybe (with the engine off!) suck (or is it blow?) on the open port of the solonoid and see if it's passing air. Though I'm not sure if it's normally open and the controller shuts it to maintain boost or the other way round. I'll check later tonight.
Or block the vent port and take it for a gentle run- with a caution that doing this may lead to an overboost and the controller won't be able to bleed off the actuator pressure.
Edit:
Nope, I thought about this again and I'm wrong. A faulty solonoid would just mean no or full vacuum pulling on the wastegate actuators.
If there was no vac, then the wastegates would just be held shut by the springs (full/overboost). With full vac (ie no air being bled in via the solonoid) then the gates would be pulled open limiting boost.
So, I'd second the guess that it's the rod from actuator to gate that's come off.
If it were jammed open then that would limit the boost.
How to test....
Maybe (with the engine off!) suck (or is it blow?) on the open port of the solonoid and see if it's passing air. Though I'm not sure if it's normally open and the controller shuts it to maintain boost or the other way round. I'll check later tonight.
Or block the vent port and take it for a gentle run- with a caution that doing this may lead to an overboost and the controller won't be able to bleed off the actuator pressure.
Edit:
Nope, I thought about this again and I'm wrong. A faulty solonoid would just mean no or full vacuum pulling on the wastegate actuators.
If there was no vac, then the wastegates would just be held shut by the springs (full/overboost). With full vac (ie no air being bled in via the solonoid) then the gates would be pulled open limiting boost.
So, I'd second the guess that it's the rod from actuator to gate that's come off.
Edited by Green3R on Wednesday 17th June 07:45
The C clips rot to nothing and then the actuator arm can fall off the spigot completely which leaves the wastegate penny flapping about. It'll then never close so all you'll get is vacuum up to a maximum of 0. With twin turbos you can generate a small amount of positive pressure from the other if only one has failed but it'll be fairly negligible.
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