Under Drive pulleys

[Mest30]

I installed my UD pulleys about 3-4 weeks ago and ever since, my speakers put out a very annoying buzzing noise, especially when the car is in gear but stopped. The volts also goes to 12ish when the car is in gear but stopped. Driving, it's fine, except for the buzzing for the speakers. I did not install the alt pulley. If I did, would the noise go away? My system includes 1 amp and 4 6x9s. I also have 2 10s hooked up to another amp but disconnected the speakers after the UD pulleys were put in. Any suggestions on how to get rid of that noise? Thanks.

[CRUZTAKER]

The factory system on mine did not suffer from dc line noise after pullies.

The idle did drop, and at night with items on with headlamps it was clearly noticable.

I corrected that with my SCT by bumping up my idle rates in all occurances.

Good luck with that line noise, and let's hope it was just a coincedence in some way. Check all your grounds and perhaps add an inline rca noise filter.

[Mest30]

Thanks for the suggestions. I'm going to pull my subs and all wires associated with it. That should help.

[Blackened300a]

Bumping up the idle with a tune solves any charging issues with the U/D's

[fastblackmerc]

Like they said increase your idle speed by 200 RPMs. No radio / noise issues after I installed my UD's.

[RF Overlord]

The volts also goes to 12ish when the car is in gear but stopped. I did not install the alt pulley. If I did, would the noise go away?Since the alternator is turning at a slower speed now, it's normal for the voltage at idle to drop a little. As others have said, have your tuner bump the idle-in-drive speed up by 100-200 rpm. Installing the alternator pulley will only make the issue worse, as the alternator will turn even slower.

It's not possible for underdrive pulleys to cause a buzzing noise in your stereo. All U/D pulleys do is slow down the accessories a little.

[Peace2Peep]

It IS possible that the installing of the pully on the alternator damaged the alternator or if they removed the alternator to install the pulley they reinstalled the alternator improperly. But it could also be that you just have a bad ground and less voltage makes it worse.

[RF Overlord]

He said that he did NOT install the alternator pulley...

[Mest30]

That is correct, alt pulley not installed. This weekend I'm taking the subs out and all the wire associated with the subs and see if that helps. I have the subs disconnected now because there is a bad wire some where that is causing constant bass coming out of the subs. Whatever the bad wire is or where ever it is, may be causing the buzzing noise coming from the 6x9s.

[Professor]

If you have a Lidio tune, how do you bump up the idle RPM's? Isn't the tune proprietary?

[Local Boy]

On the contrary, Your tuner has parameters you can adjust yourself..."Drive Idle Speed" is one of them...

On your tuner, go into "install tune"..."change parameters"...scroll down to "drive idle speed" and simply increase by @ 200 rpm's (@ 760 rpm's)

Save your changes...and your done...

ALOHA