Hoping someone can help with this issue I am having with my cars performance. I have been getting the annoying half engine power light come up when accelerating hard past 4k revs with the 'boost-pressure control deviation plausibility' code coming up. Have performed a walnut blast on the intake valves whilst also checking all the hoses to the turbo etc. I have noticed that there are two hoses that aren't connected to the vacuum tank and wondering if this may be the cause? I have tried to slip both tubes back over the plastic tubes on the tank however it seems the hoses are too big and just slip right off. Upon inspection they are very short pieces of hose that slip over the harder lines so could they have become worn and need replacing? If so where can they be sourced from? Have attached some photos for reference.

 

These loose hoses will definitely keep your waste gate from actuating. Check https://www.realoem.com/bmw/enUS/select for the hose set part number, then browse our forum suppliers for availability. Or, if in a hurry, cut off the large ends and replace them with generic vacuum hoses, just use common sense when choosing the hose size and attaching them to the old set. 2nd choice --- find a couple small hose clamps to secure the loose ends to the vacuum tank.

 

Thanks so much for your reply! I went with your suggestion of getting some generic hoses so popped over to Repco yesterday and got some hose and connected them on along with two small clamps on the tank side to doubly make sure they stay on. Took the car for a run once I had everything bolted back up and it's giving full boost again and pulling like a train! No more half power engine light! Such a relief to have it running nicely again. Next job is getting the aircon gas refilled for the humid summer here in Australia. Thanks again dude!

 

Suggest you replace all of the rubber vacuum lines since it is clear that the bits you replaced have aged out.

 

Yeah probably not a bad idea. This car has had quite a few parts replaced over the last year including new engine fan and new clutch and flywheel.