I can't solve my emi problem
 

Grasping at straws, hoping a true expert is out there.

I have a custom autosound radio and a small 4 ch Jensen amp and a Rockville under seat sub.

Sounds great with engine off. When running, I have a whistle that changes pitch with engine RPM.

I have searched the internet for a solution. I have worked thru all kinds of checklists. I have watched dozens of "expert" videos. Nothing works.

I have:
-LS swap
-4 ga power and ground
-1 ohm resistance to ground from amp to battery
-grounds battery to motor, motor to frame, motor to cab all clean
-grounded the head unit to the battery to insure a perfect ground
-power to head unit is direct from fuse panel AND has a filter on it
-RCA connections have filters
-bypass the amp, still have the noise
-bypass the head unit (ie bluetooth adapter direct to amp) still have the noise
-move the bluetooth adapter all around the cab, still have the noise and does not even change pitch.
-had a spare alternator so I changed it. didn't help
-changed the spark plug wires, didn't help

Any ideas? Thanks in advance.

Re: I can't solve my emi problem
 

Unshielded wires in the audio system are acting like antennas, picking up RF from alternator, ignition, electric motors, etc.. Install RF by-pass capacitors on these wires. Sometimes small value .001 mfd will work.. I recommend .01 mfd.

Re: I can't solve my emi problem
 

Not an expert but I remember that whine from the CB era. Usually the alternator. At the time I just lived with it. The factory radio was shielded, the CB not so much.

Quick test. Disconnect the alternator both main wire and plug. Start the motor. If it still whines, not the alt, if the whine is gone, alt. If it is the alt, make sure the suppression capacitor is installed. Not all alts came with and it is often skipped by the China rebuilders.