Hi mate

Out of curiosity, I assume your boost gauge would normally show vacuum as well as boost?

If so, when you have engine on and no throttle, it is running on vacuum, like a naturally asparated engine. If the engine is off, then it should be centred at 0. If the needle is not moving at all, then it is a good chance that you have a breach on your pipe connecting the boost gauge to your plenum.

Is the above the case? If so, trace the pipe back to plenum, unplug and seal, and try again. If this is the case, then you know the problem is either in the gauge or pipe to it (more likely).

Let me know if the above symptoms are correct, or if it is just not making postiive boost, which could be many other things

JJ