Still pulling hair out with this,
I found a perished top hat blank on the vacuum system close to the battery, have sorted that, bypassed all of the metal pipework replacing with miners vac pipe, all solenoids, the boost sensor and now the actuator to the vgt changed with genuine parts...
And yet, however I setup the turbo I occasionally get this fluctuating boost, usually under half load to a beat of about once a second. The boost can vary between 0.4 and 1.2 at worst.
I have cybox system, no cat and the egr removed
All leaks are plugged, all the hardware bar the vac sensor t'd into the vgt line on the tb is brand new. I just don't get it
Currently have turbo setup with alot of preload on the actuator, which seems to reduce the issue slightly.
Short of a new ecu I can't see what else it could be!
Any ideas hugely appreciated!!