alternator whine, ground loop problem, need help

[Rich Schenk]

Try grounding hu to battery. Usually fixes the issue. Also ground amps to frame ground that could also be your issue

[ahardb0dy]

What I tried today so far.

Isolated the headunit from the metal dash, ground wire to normal spot on mounting bracket, whine still present, starts around 2800 rpm

used a self tapping screw right into the floor, removed paint to bare metal moved radio ground wire to this screw, whine still present

unplugged sub amp, whine still present

re-connected sub amp, unplugged front amp, no whine

Got home, put radio back in perm, reinstalled all removed parts, ground still to screw in floor

Added a ground wire from mounting screw of front amp (Orion 275SX) to ground distribution block, test drive in a minute

[ahardb0dy]

the extra ground wire from the amp chassis to ground did nothing,

I removed the Orion amp ground from the dist. block and removed the trim below the rear window, cleaned the paint off in a spot down to metal and attached the Orion's ground wire directly to the metal, whine seems to have gone away !

Will know for sure tomorrow when I go back to work, long drive

Thanks all will update tomorrow after work.

[MADVIBES]

run a four gauge ground from the battery all the way back. problem solved..

[RooTxBeeR]

run a four gauge ground from the battery all the way back. problem solved..

I have always done this. I have seen the debate about running a ground wire and using frame as ground. When ever I see people with alt wine issues, it's damn near always, they use frame grounds. I have always ran a ground with my power to the back and never had this problem. Only time I did was when an RCA wire was shot and was bringing in noise to the signal.

[ahardb0dy]

Watched a video last night where they measured voltage loss ( think that's what it was anyway), using a Newer Nissan Altima with a couple amps in it, they measured at the negative battery terminal using the body as the ground, than using 1-0 cable to the battery and it did better using the car as the ground.

The last time I had any alternator whine was way way back in my 80 Datsun 310GX, alpine shaft type cassette deck with a FAS EQ/booster and 2 door speakers, it was so bad the shop put some kind of filter on it and it was OK after that.

I have had 3 Nissan trucks, all headunits grounded in the same place, my former 87 4x4 had the same PPI 2200 amp I am using now, and a 4 ch. Alpine (3554), various EQ's over the years, JVC dual bands (front and rear), Alpine 11 band, Alpine 3342, Sony Headunit XR-U770, no noise ever.

Than a 94 Pathfinder, Alpine headunit from 94, Cerwin Vega 4 ch amp, Alpine ERG180 EQ, no noise problems

my current 93 hardbody

90 Nissan sentra, Sony Headunit, Alpine 3342 EQ ( different one), PPI 2200 amp, Alpine 3454, than a 3455, than a POS crunch amp, than the ORion 275SX, no noise problems, grounded to the rear fender using a self tapping screw.

No idea why all of a sudden I was getting alternator whine in my 93.

[Robert Bronner]

http://www.bcae1.com/images/rca/temporaryrcashieldrepair.html​

Just wired some fuses to a Pioneer DEH P7700mp head unit the other day and sounds like new. Did this to my DEH P6800MP a months back and I just used wire and grounded a speaker wire and it came back just as bad. I done the fuse to a few other head units and they have all worked fine. The only one I had a problem was the 6800 that I only used wire in a rush and now it makes noise. Check to see if it has a pico fuse . This will work.

[Robert Bronner]

http://www.bcae1.com/images/rca/temporaryrcashieldrepair.html​

Just wired some fuses to a Pioneer DEH P7700mp head unit the other day and sounds like new. Did this to my DEH P6800MP a months back and I just used wire and grounded a speaker wire and it came back just as bad. I done the fuse to a few other head units and they have all worked fine. The only one I had a problem was the 6800 that I only used wire in a rush and now it makes noise. Check to see if it has a pico fuse . This will work.

[Robert Bronner]

http://www.bcae1.com/images/rca/temporaryrcashieldrepair.html​

Just wired some fuses to a Pioneer DEH P7700mp head unit the other day and sounds like new. Did this to my DEH P6800MP a months back and I just used wire and grounded a speaker wire and it came back just as bad. I done the fuse to a few other head units and they have all worked fine. The only one I had a problem was the 6800 that I only used wire in a rush and now it makes noise. Check to see if it has a pico fuse . This will work.