For the last few months I have been trying to fix a whine coming through the car audio system when the engine is running. It came on all of a sudden, and only on the front speakers which are powered by separate amp and go through crossovers. The noise is present no matter what input chosen: tuner, CD, aux, USB.
What I have tried :
-redid all grounds, signal, and power leads to front speakers, crossovers, and amp
-ran new power and ground wires to head unit
-swapped in another amp
– tried alternate pair of rca jacked leads from head unit to amp, straight run, not crossing power lines
– new antenna and lead to head unit (old one was really bad at head unit)
– if I grounded amp directly to battery post instead of body, noise was louder. BTW, the amp ground wires are a short run twisted trio.
-pulled alternator brush pack and cleaned connections
-pulled the noise reducing capacitors on alternator and cleaned connections
-removed the diagnostic plug (TDC sensor lead and plug) from alternator
-pulled distributor cap and cleaned, above and below black plastic shield
-cleaned up edge of rotor
-cleaned all the grounding points (pivot bolt area etc) on alt. body
I did notice that the whine would disappear if the radio antenna was not connected. I talked to a few people and most told me to install a ground loop isolator on the low level lines from head unit to amp. Yesterday I talked to an ex-car audio installer and he advised to try grounding the RCA jack shields. That advice and the information here, convinced me to try it, and miracle of miracles, IT WORKED! Not a hint of noise or whine. To say I’m chuffed would be an understatement.
The head unit is a Pioneer DEH-P5000UB.