Re: electronic vacuum control switch 745i (archive)

I'll check the routing of the hoses on my switch tomorrow and let you know. It only has two input port connections both located on the intake to the turbo. The third port is an output and goes to the wastegate. I was under the impression that the switch was only connected to the knock sensor control and doesn't affect boost in any other way. I had 3 psi turbo boost also and traced it to an incorrect routing of the hoses. I believe that the upper port on the intake to the turbo and the wastegate port will give you that. Try the lower port. I wouldn't worry about the plug not being connected as it doesn't seem to have any feedback. It just operates the solenoid in the valve to pass the wastegate a different port signal.

demet

My 745i is absent of an electronic vacuum control switch for the turbo boost pressure control. I have contacted a dealership and they said there are none of these in the US or in europe. I find this hard to believe but none the less I would like to find one. I know I can fool the wastgate by a bleed control valve but I don't know how this will effect the computer since there is an electric plug that is not conected to the electronic control switch. This switch controls boost as well as anti-knock control. My problem is this, I only get three psi w/o the valve, and I would like to obtain stock boost pressures w/o having to jerry rig the vacuum lines. This has already been done (by one of the previous owners), and I am trying to work backwards to fix what somebody else F*#@ed up. If you have a parts car or know where I can find one of these switches or can tell me how this switch controls the timing and the associated anti knock control for the boost. Please please please let me know.

Lack of Boost makes me sad,

Brian Nawrocki
85 745i

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