MS1 and JY-MCU bluetooth module
 

I have a strange problem I've been experiencing with my MS1 and one of these bluetooth modules. I have used this module with a friend's Adaptronic ECU just fine - I pair up with it and Adaptive Tuner works first time, 100% of the time.

I can program it just fine, pair with it and use it with some serial devices I have here (a Cisco router among them). For what it's worth, it's at 9600, 8, N, 1. But when I plug it into my MegaSquirt 1 and then use TunerStudio with it, it just flat out doesn't work. Shadow Dash MS can't recognise the ECU and msDroid can't figure out the signature.

So I hook up to it with PuTTy (or any terminal program, eg HyperTerminal, TunerStudio's Mini Terminal), and this is what I see after typing "S":
You can see bits of what appear to be the "MS/extra hr" etc init string are trying to be sent, but the rest of it is garbage.

This continues until I enter "S" again, or even "P".

So, for the next test, I leave everything as-is, but I connect the USB->serial adaptor into the female side of the BT, and into that I plug my laptop. Again, I connect to COM13 using Mini Terminal. Setup is: MegaSquirt->BT->USB/Serial->laptop. I type "S". Response:
It works! I'm definitely connecting to the bluetooth interface because I can hook up to it with my phone both using Shadow Dash MS and msDroid just fine.

If I unplug my laptop and plug the USB->serial adaptor's USB end into a generic USB phone charger, then again, it works great.

So then I tried leaving the USB end of the USB->serial adaptor disconnected. Setup: MegaSquirt->BT->USB/serial. I hook up to the terminal again, and enter "S". Response:
So it's just spitting out the first three bytes connection string over and over again.

Then while this is being spat out, I pull the USB->serial from the end of the bluetooth completely. Setup: MegaSquirt->BT. Output:
Back to square one: The MegaSquirt can't talk to the Bluetooth adaptor properly without a powered USB->serial adaptor on the other end.

Any ideas why I just can't have it functioning with just the bluetooth adaptor?