I can't solve my emi problem

[Dead Parrot]

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.