About Rick Mieras Expertise Owner of a SAAB 9000 since 1987. I have the factory manuals, and am a
do-it -yourselfer whenever possible. I am an avionics technician in the
military.
Expert: Rick Mieras Date: 2/13/2002 Subject: Engine noise in radio
Question I have a 1989 Saab SPG. The radio plays fine
with the key on. When the engine is started the
engine noise comes through the radio. When the
engine speeds up so does the roar. The opposite
when slows down. Rear speakers are not working.
An audio expert? said both the radio and amplifier are bad. He then sort of backed off that diagnosis but decided he couldn't work on it.
If the radio is bad why then does it play OK unless the engine is running? Thanks for any help.
Answer Most radios have an input filter to remove alternator whine and ignition noise from the amplifier inside. You either have a bad ground somewhere, or the radio is amplifying the noise instead of filtering it. As far as your rear speakers are concerned, most likely the rear amp is gone, but have it checked, it could just be a disconnected wire, burned out fuse, or the radio is not sending it a signal to amplify. Hope this helps, it's hard to desnag an audio system over the net! You could try to reduce the noise by adding an inline noise filter to your positive power lead....
