ECU interference on door speaker

[Ameer Antar]

Hello all,
I've just installed a new ECU in my 5000 turbo. I strated to notice that I'm getting a lot of interference from it on the right front door speaker. I actually had to route new speaker wire near the ECU to get to the speakers becasue the car did not originally have door speakers. Has anyone else had noise issues with that speaker?

 
I did a little troubleshooting, but now I'm stumped... I figured if I disconnect that speaker from the amp, I'd be OK, but it just moved the noise to the rear speakers. What's also strange is the noise is really only audible when the headunit (and amps) are on. I tried disconnecting the amp for the door speakers (power and audio cables), but the noise just went back to the speaker near the ECU.
 
It'll be difficult to reroute the wire the way it is under the carpet. Is there any shielding that might work on this? Thanks.
 
-Ameer