alternator whine when a/c compressor is on. wierd.

[alkemyst]

the car is a 98 240sx if it matters. Big three were done, alternator is new.

I have been battling an alternator type whine for months trying to figure out why.

My radio is picking up the a/c compressor (the electronic clutch probably). If I disconnect the tweeters it seems to go away, but it may just be because I am cutting out that frequency.

Anyone know a way to filter out a/c compressor noise.

[the converted]

Where are you crossovers mounted and what else are you using in the system? Amps, deck?

[alkemyst]

Xovers are in the trunk, amp is a MB Quart RAA4200, deck is a kenwood kdc-x990. 1 pair of CDT CL62's and 1 pair of ID10's both off the amp.

Wiring is 1/0 going back, 4g to the amp. short 1/0 ground to a solid block and a sanded down point.

RCA's pulled and the noise is still there. Originally I thought it was my xovers picking up radiant noise.

It's wierd.

[the converted]

I was kind of expecting you to say the crossovers are in the trunk. Pull the tweeter wires off and see if they still make noise (i'm guessing they will). If they do run new speaker wire but put it in a drill and spin it before you run it so that it will cancel the noise.

[alkemyst]

I was kind of expecting you to say the crossovers are in the trunk. Pull the tweeter wires off and see if they still make noise (i'm guessing they will). If they do run new speaker wire but put it in a drill and spin it before you run it so that it will cancel the noise.

The speaker wire is already twisted. http://www.knukonceptz.com/pro...Kable

16g Karma from Knukonceptz

Also it seems the whine goes away when I unhook the tweeters from the xover.

Thanks

[the converted]

Well to see if the crossovers are picking up noise, disconnect the inputs to them and see if the noise goes away, if it doesn't try wrapping the crossovers with tin foil.

[alkemyst]

Well to see if the crossovers are picking up noise, disconnect the inputs to them and see if the noise goes away, if it doesn't try wrapping the crossovers with tin foil.

I will try the tin foil...I know if I disconnect the inputs the noise is still there.

Thanks

[alkemyst]

haven't had a chance to try the tin foil yet...but it's not just the a/c compressor causing this... I thought I had figured it out on Friday that it was the a/c.

Went to a remote area and revved the engine tonight...the noise is there a/c or not.

Maybe next weekend I will dismantle and try tin foil.

[BigOh8524]

Does the noise sounds like a bottle rocket kinda and the higher the RPM the faster the bottle rocket sounds? And also I've noticed it's been almost 2 months since there a post, still having the same problem?

[alkemyst]

still having the problem, but haven't really tried to fix it due to other 'priorities'

I am pretty sure it's my crossovers. I just have to sit down and figure out a new place to mount them.

[Looneybomber]

How do you know you're not getting electrical interference through the ground on your head unit or amp?

*edit* I just read the posts within this thread and saw this.

RCA's pulled and the noise is still there. Originally I thought it was my xovers picking up radiant noise.

Check that ground on the amp. If you can, grab some more power wire, (4ga, 8ga, 10ga, whichever. We just need wire for testing purposes.) and run your ground directly to the battery.

[240nspec]

Too much load on Alt.? Perhaps sourcing too much current? Previous car had this problem, a high pitch wine. Non belt issue. Ran a SHIELDED ground (unshielded did not work in my case) from alt to battery ground. My entire engine bay is hyper grounded, solved whine issue with ground to alt. Very repeatable as well, I can pull of the ground, whine comes back. 4ga ftw. Perhaps worth a cheap try?

[alkemyst]

Shouldn't be overloaded...I did the big three with 4awg already...didn't use shielded, maybe I can try that...easy swap.

[Looneybomber]

What is this "big three" you keep speaking of?

[alkemyst]

What is this "big three" you keep speaking of?

It's a well-known/used term to refer to the block to chassis, battery to alt (postive) and battery to chassis leads.

[Looneybomber]

Oh I gotcha.

Have you tried wiring the amp ground directly to the battery yet?

[alkemyst]

Oh I gotcha.

Have you tried wiring the amp ground directly to the battery yet?

I will give it a shot. I am coming back with 1/0 gauge though to 4awg to my amp..my block is grounded to the chassis with 1/0 gauge as well.

[the converted]

Sorry I'm late to the second party but have you tried wrapping the crossovers with tin foil yet?

[alkemyst]

I haven't had a chance to revisit it. But I will be trying this and some other suggestions.