The patient is Golf 2.0 TDi year 2005 BKD-engine.
When accelerating it gets into Limb-mode because of excessive boost in turbo. And gives the related error code, and the same can also be seen in pressure changes via VCDS.
VCDS shows that the ECU's requested pressure will be exceeded by actual pressure in turbo, when hitting the pedal to metal - and when that situation lasts long enough, the engine goes to limb -mode. That will happen every time. But also - if the acceleration is done carefully and following that the vacuum figure in the pipe from N75 block to vane actuator (yes, I connected there a gauge to see the vacuum) will not go too high, one can get even 170 km/h speed w/o issues.
We cleaned the turbo by loosening the exhaust pipe from turbo and turning it to aside and sprayed Mr. Muscle into the turbo - twice; washed it with water. Moved the vane actuator with vacuum pump to get that better cleaned. Now the vanes move easier and all the way when giving vacuum with a separate vacuum pump. But so far we have not installed any camera to see how it behaves on highway speed - does it move and return when the vacuum from N75 is changing accordingly.
We also tested that the vacuum from N75 behaves normal way - the N75 valve solenoind works. We tested it with two separate N75's valve blocks - both working same way: when idle, the vacuum is 20. When gas pedal is hit, the vacuum drops in second to <5 and jumps then backwards close to 20; depending of the rpm.
We eliminated EGR action/leak by closing its actuator's vacuum line - no changes; we also tested its possible leak. Nothing.
If we pump vacuum to the pipe line from manifold to the N75 valve block, it does not keep the pressure steady - it slowly leaks. Should it not? But if we pump the vacuum to the pipe line from valve block to the turbo actuator, that does not leak at all.
We do not understand why the system does not work properly, but goes to limb mode because of excessive boost, if we have N75 working properly and we can move the vanes with a vacuum pump.
Can anyone help what to test/check or even where do we have the possible mystery key?
Rgds,
Two old neighbours from Finland having quality time with golf.
When accelerating it gets into Limb-mode because of excessive boost in turbo. And gives the related error code, and the same can also be seen in pressure changes via VCDS.
VCDS shows that the ECU's requested pressure will be exceeded by actual pressure in turbo, when hitting the pedal to metal - and when that situation lasts long enough, the engine goes to limb -mode. That will happen every time. But also - if the acceleration is done carefully and following that the vacuum figure in the pipe from N75 block to vane actuator (yes, I connected there a gauge to see the vacuum) will not go too high, one can get even 170 km/h speed w/o issues.
We cleaned the turbo by loosening the exhaust pipe from turbo and turning it to aside and sprayed Mr. Muscle into the turbo - twice; washed it with water. Moved the vane actuator with vacuum pump to get that better cleaned. Now the vanes move easier and all the way when giving vacuum with a separate vacuum pump. But so far we have not installed any camera to see how it behaves on highway speed - does it move and return when the vacuum from N75 is changing accordingly.
We also tested that the vacuum from N75 behaves normal way - the N75 valve solenoind works. We tested it with two separate N75's valve blocks - both working same way: when idle, the vacuum is 20. When gas pedal is hit, the vacuum drops in second to <5 and jumps then backwards close to 20; depending of the rpm.
We eliminated EGR action/leak by closing its actuator's vacuum line - no changes; we also tested its possible leak. Nothing.
If we pump vacuum to the pipe line from manifold to the N75 valve block, it does not keep the pressure steady - it slowly leaks. Should it not? But if we pump the vacuum to the pipe line from valve block to the turbo actuator, that does not leak at all.
We do not understand why the system does not work properly, but goes to limb mode because of excessive boost, if we have N75 working properly and we can move the vanes with a vacuum pump.
Can anyone help what to test/check or even where do we have the possible mystery key?
Rgds,
Two old neighbours from Finland having quality time with golf.