Wow, I'm experiencing something similar. I'll start the engine and the Z130BT buttons and screen won't light up for about 20 seconds. I've noticed that lingering in accessory for a bit before starting sometimes helps.
Here's my build:
- 2011 WRX
- Z130BT new
- Axxess ASWC
- ND-BC4 backup camera
- Navi Bypass
- VSS + Reverse taps
Before I start tearing through my wiring, anyone have any ideas what the problem might be?