Charge Pressure Control - What's going in on here?
Car Octavia 2 1.9 PD BXE
Still trying to work out why engine missing/surging and poor/non starting when hot
Was looking at the idea that Engine note should change when you disconnect MAP sensor - No discernable change in engine note when disconnected or reconnected.
Looking in more detail I looked at Group 11 - Charge Pressure Control, while also looking at vacuum in line from solenoid valve block to turbo actuator. Gauge was connected with a 'T' so function of vacuum line should not be disturbed.
So as table below describes, ran at idle then disconnected MAP sensor then reconnected.
What struck me was that Boost pressure at idle is less than specified - aware that they will not always match perfectly but I presume this deviation is outwith normal limits.
Then although disconnecting MAP sensor changed CPDC, vacuum to turbo actuator and actual boost pressure, reconnecting MAP sensor made no difference to readings (stayed as they were when it was disconnected). Switching engine off then on again caused the readings to go back to almost exactly initial values.
I am thinking this is not quite right and hopeful there are some clues in here, but don't quite know what to make of it. Any ideas appreciated.
Thanks
VCDS RPM is not continuous - goes up in steps . Presume engine speed must have been right on boundary between these two values as it was alternating between 819 and 840
