02 4 Runner stereo feedback from engine

[Oldwizer]

We have an 02 4-Runner that gets a high pitched noise from the stereo only with the engine running. Happens on AM or FM and raises and lowers in pitch along with the engine rpm. The dealer is cluless as to the cause and has replaced the radio 3 times and the amplifier twice. I tried clipping a wire to the antenna and moving the end around the engine compartment to see if I could notice a change in volume but no joy. Any ideas folks? Thanks.

[johnnyzee]

sounds like "alternator whine". basically, your amp/ h/u is getting feedback from the alternator. here's the list of probable cases:

1. your rca's or signal wire from the h/u feeding the amp is in direct contact with or too close to a power wire, either behind the deck, along the side panels, or in the trunk (if thats where it's mounted). this is the usual case in an aftermarket setup.

2. if your amp is a stock factory kind, then the wire runs were mostlikey run properly. check to see that the wires feeding the amp are not anywhere pinched against the car or a screw knicking them. this will cause a ground feedback which is where you could get the noise from.

3. check behind the deck that no pinching or knicking occured during the installation.

4. basically make sure the grounds points are good (making good metal to metal contact) behind the h/u and the amp. clear any paint or rust / corrosion away from the connections. check your rca cables, and keep the rcas away from power wires.

good luck

[bigloubumpin]

U never mentioned,is it OEM stuff?

[Oldwizer]

Thanks for the info Johnny I will check out your suggestions and yes it is OEM. Thanks.