Ok, so here's the background on it. Had my 87 TII since June, put an MSD 6A in yesterday using Ted's instructions. Runs great, no problems. However, on the way home from work tonight I noticed a whirring/whistling sound that rose with RPM until the turbo spooled up and drowned it out. So while wondering what this was, I experimented a little. Turns out if I slightly touch the brakes, just enough to light the tails up, not actually slow down, the noise goes away (also my gauges get ever so dimmer). Also, if I turn the headlights off (no I didn't do this while moving), the noise goes away. So I can recreate it by turning on the headlights and not touching the brakes.

Any ideas what this is? I thought maybe it was just some interference through the wiring but even with my stereo shut off the noise was still there.

I can try to take some audio of it tomorrow, not sure if the noise will get picked up though, it isn't very loud.

 

Ok no audio or video but I fixed it. What seems to have happened was, since I did all the wiring inside (it was cold in the middle of the night in the garage), I left extra length of wire between the MSD and the coil, just to be safe. After I installed it I didn't have time to clean it up and make the wires the right lengths so I just looped the extra around one of the battery tiedown posts. Well, I forgot my basic electrical engineering here, where electricity going in coils makes a field.

Long story short, I shortened the wiring to the correct length today and no more whirring noise.