Couple of car troubleshooting questions anyone?

June 8, 2008 11:27 AM

Snazzy Blaupunkt stereo installed in car, but I find myself plagued by a whine which I am assuming is originating at the alternator. If anyone could explain in simple terms how I might be able to eliminate this noise without too much fuss I would be really grateful!

I realise it's almost always a grounding issue or speaker/power cables getting tangled together - but I haven't a clue how to go about re-grounding the stereo when it's so tight and dark behind the dash. Strangely the last stereo had no such problems, was also Blaupunkt and the new stereo was able to use the same connectors. Ignoring the fact the stereo itself is changed, the back of the stereo still looks a lot like this.

Plus! Huge bonus points if someone could suggest why my front left wheel sounds wobbly when driving on unmetalled roads even though the roll bars have just been changed....

posted by dance to travel & transportation (6 comments total)

Google for something called a ground loop isolator. Thats what needs to be installed in your car to stop the sound.
posted by damn dirty ape at 12:39 PM on June 8, 2008

Could be a whole bunch of reasons, including:

• Signal wires aren't shielded well
• Signal wires run next to power
• Failing alternator (has to work harder->more RFI)
• Improper grounding (multiple grounds spread apart from each other, for instance, or bad contact with chassis metal)
• Other...

This thread might provide some insight.
posted by Civil_Disobedient at 1:30 PM on June 8, 2008

If you're sure it started exactly when the new radio was installed, you'll have to double check your install. Does the radio have higher requirements? Maybe the radio itself is faulty? Or, maybe the old radio had better/different noise reduction circuitry that masked a problem that actually existed for some time. Maybe a wire popped loose or one of your splices went bad.

Does the noise vary with engine speed? It is more of a high pitched buzz, almost like one of those Jetsons flying cars (minus the bubbly sound)? If it's that, yeah, it sounds like alternator noise to me.

Another test would be to verify if the sound occurs when the engine is not running. If it happens when the car is off, then it can't be the alternator.

Does it happen on all inputs (CD, AM, FM)?

Have you checked your battery cables to make sure they are tight and clean?
posted by gjc at 3:20 PM on June 8, 2008

to answer the wobbly wheel question.

Your roll bars have (almost) no influence on how your wheel is attached to the car. So its replacement would have no effect on the 'wobblyness'.

My first guess is either a bent rim or a damaged tire. low profile tires are much more susceptible to this than normal sidewall height tires. After that it goes wheel bearings and then balljoints on the a-arms and the steering tie-rod. I don't think it's a balljoint because your not complaining about it being out of alignment(pulling to one side) or being 'darty' (pulling to alternating sides).

is the steering wheel centered?

you could also be getting wierd effects if the car has been lowered and the camber has not been brought back into line with the proper adapters or spacers.

Also, whats an 'unmetalled' road?
posted by TheJoven at 3:44 PM on June 8, 2008

You probably need a noise eliminator similar to this. You wire it in series with the 12 V feed into the stereo.
posted by rfs at 8:08 PM on June 8, 2008

I've had the alternator noise before. I went back in and basically re-connected every wire, making sure they were as solid as possible. That fixed it.
posted by PFL at 7:32 AM on June 9, 2008